I lllll 1111111111111111111111111111111 IIIII IIIII lllll lllll 111111111111111111
`US005322075A
`5,322,075
`[11] Patent Number:
`[45] Date of Patent:
`Jun. 21, 1994
`
`4,947,875 8/1990 Brooks et al ........................ 131/330
`4;981,522 1/1991 Nichols et al ....................... 131/274
`5,060,671 10/1991 Counts et al. ....................... 131/329
`5,093,894 3/1992 Deevi et al .......................... 392/390
`5,095,921 3/1992 Losee et al .......................... 131/194
`
`FOREIGN PATENT DOCUMENTS
`029S122 6/1988 European Pat. Off ...... A24F 47/00
`0358002 8/1989 European Pat. Off ...... A24F 47/00
`0358114 8/1989 European Pat. Off ..... A61M 1S/00
`WO89/06480 12/1988 World Int. Prop. 0 ...... H0SB 3/10
`Primary Examiner-Theatrice Brown
`Attorney, Agent, or Firm-Kevin B. Osborne; James E.
`Schardt; Charles E. B. Glenn
`ABSTRACT
`[57]
`A smoking article is provided in which a flavor-generat(cid:173)
`ing medium is heated electrically to release an aerosol
`for inhalation by a consumer. The smoking article in•
`cludes a heater having resistive heating elements
`printed on a flexible substrate. The heater can be manu(cid:173)
`factured by circuit board mass production techniques,
`and can be formed to fit inside an article of the same
`shape and size as a conventional cigarette. Alterna(cid:173)
`tively, the heater comprises an array of heating ele(cid:173)
`ments onto which charges of flavor-generating medium
`are deposited. The heating elements are connected in a
`manner which allows the temperature increase in the
`heater to be concentrated in individually selected heat(cid:173)
`ing elements, and requires a minimal number of electri(cid:173)
`cal conductors.
`
`57 Cairns, 2 Drawing Sheets
`
`;}121
`
`I 123
`
`12
`
`10
`
`United States Patent c191
`Deevi et al.
`
`[54] HEATER FOR AN ELECTRIC
`FLAVOR-GENERATING ARTICLE
`[75] Inventors: Seetbarama C. Deevi, Midlothian;
`Mohammad R. Hajaligol, Richmond;
`Herbert Herman, Port Jefferson;
`Charles T. Higgins, Richmond;
`MicJiael L. Watkins, Chester; Bruce
`E. Waymack, Prince George; Sung
`Yi, Midlothian, all of Va.
`[73] Assignee: Philip Morris Incorporated, New
`York, N.Y.
`[21] Appl. No.: !143,318
`[22] Filed:
`Sep. 10, 1992
`Int. a.s ................................................ A24F 1/22
`[51]
`[52] U.S. a ..................................................... 131/194
`[58] Field of Search ......................................... 131/194
`References Cited
`[56]
`U.S. PA TENT DOCUMENTS
`3,444,183 5/1969 Hubbuch ............................ 260/32.6
`3,496,336 2/1970 Hingorany et al .................. 219/464
`3,563,916 2/1971 Takashima et al. ................. 252/S11
`4,016,061 4/1977 Wasa et al. .......................... 204/192
`4,194,108 3/1980 Nakajima et al. ................... 219/216
`4,203,025 5/1980 Nakatani et al ..................... 219/216
`4,259,564 3/1981 Ohkubo et al. ..................... 219/216
`4,659,912 4/1987 Derbyshire ......................... 219/535
`4,822,538 4/1989 Yoshida et al ..................... 264/29.4
`4,845,533 7/1989 Pryor et al .............................. 357/2
`4,922,901 5/1990 Brooks et al ..................... 128/203.2
`4,947,874 8/1990 Brooks et al ........................ 131/329
`201
`
`~ 114
`
`110
`
`202
`
`II
`
`31
`
`203
`
`206
`
`Ex. 2007-0001
`
`

`

`FIG.I
`
`123
`
`122
`
`114
`
`110
`
`202
`
`II
`
`12
`
`10
`
`
`
`31
`
`203
`
`
`
`206
`
`FIG.2
`
`3-I
`
`
`
`waned'S'fl
`
`
`
`17661‘129““1'
`
`207
`
`ZJ0IWalls
`
`sw‘zzs‘s
`
`•
`
`d • 00
`"'C a. ff) a
`
`a4
`=(cid:173)~
`l-.»
`j-'
`....
`!
`
`t'll [ ...
`e.
`
`l-.»
`
`...
`UI
`CN
`k,J
`...
`k,J
`0
`-...I
`UI
`
`Ex. 2007-0002
`
`

`

`U.S. Patent
`
`June 21, 1994
`
`Sheet 2 of'2
`
`5,322,075
`
`FIG. 3
`
`FIG. 4
`
`,-----0--------<;?---v+
`6
`412
`
`404
`
`405
`
`406
`
`Ex. 2007-0003
`
`

`

`1
`
`HEATER FOR AN ELECTRIC
`FLAVOR-GENERATING ARTICLE
`
`5,322,075
`
`2
`number of electrical connections to selectively concen(cid:173)
`trate power on an individual heater element.
`
`5
`
`10
`
`15
`
`BRIEF DESCRIPTION OF THE DRAWINGS-
`The above and other objects of the invention will be
`apparent from the following detailed description, taken
`in connection with the accompanying drawings, in
`which like reference numerals refer to like parts
`throughout, and in which:
`FIG. 1 is a partially fragmentary exploded cut-away
`perspective view of an embodiment of a smoking article
`including a heater according to the present invention;
`FIG. 2 is a plan view of a preferred embodiment of a
`heater according to the present invention;
`FIG. 3 is a cross-sectional view of the heater of FIG.
`2 taken along lines 3-3; and
`FIG. 4 is a schematic diagram of an alternative em(cid:173)
`bodiment of a heater according to the present invention.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`The heater of the present invention may be used in an
`electric flavor-generating article, which itself includes a
`source of electrical energy, electrical or electronic con(cid:173)
`trols for delivering electrical energy from the source of
`electrical energy to the heaters in a controlled manner,
`and a flavor-generating medium in contact with the
`heater. When the heater heats the flavor-generating
`medium, flavor-containing substance-i.e., a vapor or
`aerosol, or mixture thereof, containing flavored vapors
`or aerosols or other vapor or aerosol components-is
`generated or released and can be drawn in by the con(cid:173)
`sumer.
`The flavor-generating medium can be any material
`that, when heated, releases a flavor-containing sub(cid:173)
`stance. Such materials can include tobacco, tobacco
`condensates or fractions thereof (condensed compo(cid:173)
`nents of the smoke produced by the combustion of
`tobacco, leaving flavors and, possibly, nicotine), or
`tobacco extracts or fractions thereof, deposited on an
`inert substrate. These materials, when heated, genetate
`or release a flavor-containing substance which can be
`drawn in by the consumer. Any of these flavor-generat(cid:173)
`ing media can also include an aerosol-forming material,
`such as glycerine or water, so that the consumer has the
`perception of inhaling and exhaling "smoke" as in a
`conventional cigarette. A particularly preferred mate(cid:173)
`rial is a composition such as that described in common(cid:173)
`ly-assigned U.S. Pat. No. 4,981,522, hereby incorpo(cid:173)
`rated by reference in its entirety, which describes pellet(cid:173)
`ized tobacco containing glycerine (as an aerosol-form-
`ing ingredient) and calcium carbonate (as a filler). As
`used in the present invention, the composition, instead
`of being formed into pellets, would be deposited as a
`55 coating (in conjunction with adhesion agents such as
`citrus pectin) onto heating elements.
`The flavor-generating medium is divided into indi-
`vidual charges, each representing one puff of the article.
`It is possible to mimic a conventional cigarette by pro(cid:173)
`viding a number of charges of flavor-generating me(cid:173)
`dium equal to an average number of puffs per cigarette,
`e.g., eight to ten puffs. Although the article does not
`decrease in length like a conventional cigarette as it is
`operated, it is possible to make the article in varying
`65 lengths, with different numbers of puffs. By providing
`individual charges for each puff, one r1:duces the total
`amount of flavor-generating medium that must be pro-·
`vided, as compared wit~ a single larger charge that
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to flavor-generating
`articles in which a flavor-generating medium, for exam-
`ple tobacco, is heated electrically to produce a flavor(cid:173)
`containing aerosol for delivery to a consumer. More
`particularly, the invention relates to electrical resistance
`heaters for such articles.
`2. Description of Related Art
`Smoking articles utilizing electrical power for heat(cid:173)
`ing and thereby releasing flavor from tobacco and other
`compounds may have certain advantages over conven(cid:173)
`tional smoking articles. For example, electrically(cid:173)
`heated smoking articles produce the taste and sensation
`of smoking, but do not burn tobacco, and thus do not 20
`produce all the normal byproducts of tobacco combus(cid:173)
`tion. Also, electrically-heated articles do not produce
`sidestream smoke.
`One previous attempt to provide an electrically(cid:173)
`heated smoking article involved heating an entire bed of 25
`flavor-generating materials, each time the consumer
`inhaled, using a single heating element. Another electri(cid:173)
`cally-heated smoking article heated localized charges of
`flavor-generating material selectively, with a new
`charge being heated each time the consumer inhaled.
`There have been various technical problems with
`electrically-heated articles. For example, if a large num(cid:173)
`ber of heating elements are provided for heating indi(cid:173)
`vidual flavor-generating charges, the number of electri(cid:173)
`cal connections necessary to supply power to the heat- 35
`ing elements becomes large. This can increase the cost
`of the heater. Also, it may be difficult to mass-produce
`heaters having individually selectable heating elements.
`It may also be difficult to manufacture heaters of a
`suitable shape and size to fit into a smoking article simi-
`lar in size to a conventional cigarette.
`In view of the foregoing, it is an object of the inven(cid:173)
`tion to provide a heater which uses a minimal number of
`electrical connections to heat selectively any one of 45
`several individual flavor-generating charges.
`It is another object of the invention to provide a
`heater which can be manufactured by mass-production
`techniques.
`It is a further object of the invention to provide a 50
`heater which can be shaped into a configuration suitable
`for incorporation into a smoking article of the same
`shape and size as a conventional cigarette.
`
`30
`
`40
`
`SUMMARY OF THE INVENTION
`These and other objects of the invention are accom(cid:173)
`plished in accordance with the principles of the present
`invention by providing an electrical resistance heater
`manufactured by printing conductive and resistive ma(cid:173)
`terials on a flexible substrate. The heater can be manu- 60
`factured using mass-production printed circuit tech(cid:173)
`niques. The flexibility of the substrate allows the heater
`to be shaped into a tubular form suitable for incorpora(cid:173)
`tion into a smoking article of the same size and shape as
`a conventional cigarette.
`The heater may include several heating elements
`which are connected in a two-dimensional array config(cid:173)
`uration. The two-dimensional array requires a minimum
`
`Ex. 2007-0004
`
`

`

`5,322,075
`
`35
`
`3
`would be electrically heated or reheated once for each
`of several puffs.
`The portion of the flavor-generating article that con(cid:173)
`tains the heaters and the flavor-generating medium is
`preferably a replaceable plug-in unit, so that when all of 5
`the charges have been heated, the spent plug-in unit can
`be discarded and a new one inserted. The controls and
`power source could be retained.
`One embodiment of the smoking article 10 according
`to the invention is shown in FIGS. 1 and 2. Article 10 is 10
`the simplest form of article according to the present
`invention, and includes heater/flavor/mouthpiece sec(cid:173)
`tion 11 and power/control section 12. Section 11 in(cid:173)
`cludes a heater 110, and heater 110 further includes a
`plurality of heater elements 201, each having deposited 15
`on its surface a quantity of flavor-generating medium
`202. The heater configuration shown in FIG. 2 is illus(cid:173)
`trative only. Different possible heater configurations
`will be discussed below. Preferably, there is a segment
`of filter material 112, such as conventional cellulose 20
`acetate or polypropylene cigarette filter material, possi(cid:173)
`bly in conjunction with paper-wrapped tobacco rod
`sections, at the mouth end of section 11, to provide
`appropriate filtration efficiency and resistance-to-draw 25
`to the article. In addition, mouthpiece 113 can option(cid:173)
`ally be included.
`As shown in both FIGS. 1 and 2, there are ten heater
`elements 201 in section 11. There are also eleven
`contact pins 114 extending from section 11 remote from 30
`its mouth end-one common pin and ten pins connected
`to individual heater elements 201-that fit into eleven
`sockets 120 on section 12 to make electrical contact
`between heater 110 and power source 121, the nature of
`which will be discussed in more detail below.
`A knurled knob 122 is provided at the remote end of
`section 12 to allow the consumer to select one of the
`heater elements 201. Knob 122 controls a single-pole ten
`position rotary switch 123 connected by wires 124 to
`sockets 120.
`To operate article 10, the consumer selects a heater
`element 201 using knob 122 and presses momentary-on
`pushbutton switch 125 to complete the circuit and ener(cid:173)
`gize the selected heater 201 to initiate heating. Flavor(cid:173)
`generating medium 202, thus heated, can release or 45
`generate a flavor-containing substance. The consumer
`draws in the flavor-containing substance along with air
`drawn through perforations 126 in the outer wrapper of
`sections 11 or 12, which could be conventional cigarette
`paper or tipping paper. Air may also enter through the 50
`end of section 12 remote from the mouth end through
`channels that may be provided for that purpose, carry(cid:173)
`ing the air around power source 121 and around other
`internal components of section 12. It is important that
`the air enter section 11 at a point at which it can fully 55
`sweep heater 110 to carry the maximum amount of
`flavor-generating substance to the mouth of the con(cid:173)
`sumer.
`When all ten charges in section 11 have been heated,
`section 11 is spent, and can be unplugged from section 60
`12. A new section 11 can then be plugged in. Section 12
`as envisioned is reusable.
`A more preferred embodiment of an article according
`to the present invention includes controls that automati(cid:173)
`cally select which charge will be heated, initiate heating 65
`in response to a certain stimulus (for example, the user's
`inhalation), and control the duration of the heating of
`each flavor charge.
`
`40
`
`4
`A preferred embodiment of heater 110 is shown in
`FIG. 2. The entire heater is constructed on a flexible
`substrate 205. FIG. 2 shows a linear arrangement of
`heating elements 201 with a single common connection
`203 and a plurality of heater element connections 204.
`Heating elements 201 are deposited on substrate 205. A
`flavor-generating medium 202 (FIG. 3) is then depos(cid:173)
`ited onto each heating element. Alternatively, electri(cid:173)
`cally-resistive materials are mixed with a flavor(cid:173)
`generating medium to form the heating elements. The
`mixture is then printed on the substrate.
`Contact pins 114 or other suitable connecting means
`are provided to couple the heating elements to the
`power supply. Referring again to FIG. 1, sockets 120
`may be provided to connect heater element connections
`204 to control unit 12. Each time the consumer initiates
`a puff, control unit 12 provides power to one or more of
`heating elements 201. The powered heating element
`heats an unused charge 202 (FIG. 3) of a flavor-generat(cid:173)
`ing medium, thus releasing a flavor-containing aerosol.
`Flexible substrate 205 typically is a non-conductive,
`heat resistant material, with a low dielectric constant. In
`addition to flexibility, the substrate must exhibit good
`thermal and mechanical strength characteristics. That
`is, the substrate must be able to withstand extremely
`high temperatures (upwards of the 400° -450° C. re(cid:173)
`quired to extract tobacco aerosol), without releasing
`undesired volatiles, melting, bubbling, or otherwise
`losing its structural integrity or its flexibility. Certain
`·polyamide polymers have been found to remain stable
`and flexible under these extreme temperature condi(cid:173)
`tions. Specifically, two polymers, Upilex ® vendered
`ICI and Kapton ® vendered DuPont, exhibited no
`decomposition or deformation even at temperatures
`upwards of 500° C. Certain fibrous materials have also
`proven suitable for use in this invention. They include
`Nomex ® vendered DuPont, pure cellulose paper and
`cloth, and paper coated with inorganic salt or sol-gel.
`Common connection 203 and heating element con(cid:173)
`nections 204 can be made of any low resistivity conduc(cid:173)
`tive material. In the preferred embodiment, the connec(cid:173)
`tions are formed of conductive ink which, for example,
`may include silver in a binder such as a polyester resin.
`Alternatively, the conductors may be formed of con(cid:173)
`ductive epoxy.
`Heater elements 201 are generally made of conduc(cid:173)
`tive ink with a resistance chosen such that, when a
`voltage is applied across common connection 203 and
`one of heating element connections 204, the tempera(cid:173)
`ture of the selected heating element rises sufficiently to
`release a flavor-containing aerosol from charge 202 of
`flavor-generating medium. The conductive ink contains
`an adhesive ingredient. This ingredient has two primary
`functions in the ink; first, cohesion of the different in(cid:173)
`gredients in the ink, and second, the adhesion of the ink
`to the surface of the substrate. It is important that the
`adhesive agent maintain dimensional integrity (i.e., it
`must exhibit resistance to shrinkage and creep) under
`high temperature gradients and high electric field
`stresses. It is also important that the adhesive agent be
`resistant to moisture. Epoxy resins are good adhesive
`agents towards metals, glass, ceramics, and plastics.
`Also, polyamide epoxy resins are thermally very stable
`and exhibit good adhesion properties toward polyamide
`substrates. It is also important that the agent be flexible.
`Modification of the rigidity of the cured resin can be
`accomplished by diluting the epoxy system with low
`concentrations of other, more flexible, resins. This
`
`Ex. 2007-0005
`
`

`

`5,322,075
`
`25
`
`E =
`
`f l
`
`0
`
`...!1!L
`1'(_1)d1 = R(t)
`dt;
`
`and for constant V and R over time,
`
`35
`
`PCpai'"° = ax" Kx7x + aY KyaY +
`(
`?T )
`(
`aT )
`aT
`C
`C
`
`5
`serves to increase the average distance between cross(cid:173)
`links, and thus creates a more flexible material.
`A conductive ink should also have a solvent ingredi(cid:173)
`ent to dissolve the resins and other solutes and provide
`a uniform solution for dispersion of solid particles of 5
`interest. Suitable solvents for this invention include
`etheric or alcoholic solvents, such as glycol ether and
`isopropanol.
`The ink must have a suitable conductive agent. Fine
`particles of conductive solids such as graphite, carbon 10
`black, and metal powders can be used as conductive
`agents. Among metal powders, gold and silver are pref(cid:173)
`erable due to their high electrical conductivity.
`The design parameters, such as the physical and elec(cid:173)
`trical properties of the heater and the substrate, are all 15
`interdependent. That is, there is at least an indirect
`relation between the energy input, the heater dimen(cid:173)
`sions, the substrate dimensions, the substrate material,
`the ink composition, and the energy consumption by the
`mass of the heater. Since a part of the useful energy is 20
`used to heat the entire system, a lower mass heater is
`preferred, as is a lower mass substrate.
`The following equation illustrates the relation be(cid:173)
`tween the total energy, E, and the power, P, applied for
`the duration of the pulsing event, t:
`
`6
`for each layer with the proper initial and boundary
`conditions.
`If a highly heat resistant flexible substrate material is
`difficult to obtain, it is desirable to place an insulating
`layer between the heater and the flexible substrate. The
`insulating layer may be any non-conductive ceramic,
`inorganic, or amorphous carbon. The main goal here is
`to protect the flexible substrate from severe heating by
`reducing the heat transfer to the substrate. Also, the
`middle layer should have a high electrical resistivity to
`restrict electrical current in the layers during heating.
`This combination acts to partition the current density,
`and thus the joule heating, between the heater material
`and the middle layer. The majority of the heating, then,
`takes place in the upper layer (heater material). Materi(cid:173)
`als suitable for this application include a carbon ink
`printed on a Mylar® (vendered DuPont) substrate.
`Alternatively, and to protect the substrate if heating
`exceeds a critical value, it is possible to use a thermally
`conductive support for the substrate. Here, an example
`is aluminized paper, in which the paper is used as a
`substrate and the aluminum sub-layer is used as a con(cid:173)
`ductive layer that removes the heat away from the
`paper and dissipates it, without allowing the paper tem(cid:173)
`perature to exceed a critical value.
`Screen printing may be used to apply thick (typically
`0.5 to 5 mils) polymeric films in complex configurations.
`The viscosity of the ink must be low enough that the ink
`30 flows easily through the screen, yet high enough that it
`does not bleed into the non-printed areas of the sub(cid:173)
`strate, that is, the ink must be thixotropic. The type of
`drying employed depends on the ink-solvent character(cid:173)
`istics. When volatile solvents are used, evaporative
`drying with the aid of a dryer (air-jet, flame, micro-
`It is desired that the heater heat to at least 450° C.
`wave) is often used. Ultraviolet curing is the fastest
`during a pulse of less than one second. And it has been
`method.
`Because a thin film substrate may lack the mechanical
`determined that the maximum available energy input
`for each pulse is 2.5 calories. Considering the above-
`strength for processing on an assembly line, it may be
`described performance criteria and energy constraints, 40 helpful to either pin or glue the substrate to a solid
`support during processing. It is preferred that the sup-
`and considering further the space limitations of the
`port be a light and porous, and electrically non-conduc-
`smoking article, and the 3-5 volts available from the
`enclosed battery, it may be preferred that the heater
`tive, material, such as spongy charcoal or ceramic. The
`element have a resistance of about 1.2 ohms. With those
`porous structure is required because it carries little
`parameters set, the heater and substrate compositions 45 weight and thus has a low thermal load. It also provides
`and configurations can be optimized by mathematical
`little contact with the substrate, and conducts little heat
`modeling, as follows:
`away from the heated surface.
`Alternatively, a resistor or insulator may be deposited
`onto a polymeric substrate by thermal spraying (e.g.,
`50 plasma spraying) onto the substrate a variety of transi(cid:173)
`tion metals, alloys, or oxide ceramics. For example,
`Nichrome can be plasma sprayed onto a Kapton sub-
`strate to deposit a 1.2 ohm resistor. Transition metals,
`alloys, and oxide ceramics are thermally stable and have
`55 low dissociation vapor pressures, and thus at high tem(cid:173)
`peratures naturally exhibit high binding characteristics.
`Therefore, such metals, alloys, or ceramics may be
`deposited onto a polymeric substrate without the aid of
`polymeric binders, which binders may evolve undesir-
`60 able gases during high temperature pulsing.
`In operation, an edge 206 of substrate 205 could, for
`example, be bent over so as to come into proximity with
`edge 207 of substrate 205, and thus form a tubular(cid:173)
`shaped heater shown as unit 110 in FIG. 1.
`The screen printing process makes possible a high
`level of dimensional control, and allows one to design
`various heater configurations. FIG. 4 shows a sche(cid:173)
`matic diagram of an alternative embodiment of the
`
`+z- x,+z- + q
`
`T )
`
`•
`
`(
`
`V2r
`2
`•
`q = Vil = i RI = "-j[""
`
`av
`.lL +
`a
`a
`I
`I
`7x °R-;- 7x +ar Ff;° aY
`
`_a_
`az
`
`where Pis a density, Cpis a heat capacity, Tis a temper(cid:173)
`ature, t is a time, K is a thermal conductivity, q is a heat
`generation due to the Joule heat, V is a voltage, i is a
`current, and R is an electrical conductivity. The above
`partial differential equations are solved simultaneously
`
`65
`
`Ex. 2007-0006
`
`

`

`25
`
`7
`heater. In this embodiment, the heating elements are
`connected in an array such that a particular heating
`element can be selected with the use of a minimum
`number of electrical connectors. The array typicalJy
`includes nine heating elements, but more or Jess than S
`this number can be used. Using the square array of this
`invention, when n equals the number of heating ele(cid:173)
`ments in a row or column, it is possible to select individ(cid:173)
`ually any one of n2 heating elements with 2 n connec(cid:173)
`tors. In contrast, in a linear arrangement (e.g., as in FIG. 10
`I} n+ I connectors are required to select any one of n
`heating elements.
`Referring to FIG. 4, the connectors are divided into
`two groups termed "rows" and "columns." Conductors
`401, 402, and 403 are the rows, and can be connected to 15
`a zero voltage via switches 407, 408, and 409, respec(cid:173)
`tively. Conductors 404, 405, and 406 are the columns
`and can be connected to a power supply voltage v+ via
`switches 410, 411, and 412, respectively. One or more
`heating elements 413 can be heated by closing associ- 20
`ated row and column switches. For example, to heat
`element 414, switches 408 and 411 are closed. Switches
`407 through 412 may be transistors.
`An array heater manufactured in accordance with
`this invention can be constructed on either a flexible or
`rigid base, and can be constructed using double-sided
`printing techniques. For example, row conductors 401,
`402, and 403 can be printed on a first surface of the base,
`and column conductors 404, 405, and 406 can be printed 30
`on the second surface of the base. The heating elements
`may be connected between the row and column con(cid:173)
`ductors via perforations in the base.
`In the array configuration of FIG. 4, heating elements
`not selected to receive maximum power may receive 35
`some power via secondary routes·. The number of sec(cid:173)
`ondary routes can be reduced or eliminated, for exam(cid:173)
`ple, by incorporating a diode in series with one or more
`of the heating elements.
`Whatever heater design is used, it is subject to several 40
`design criteria. First, the electrical resistance of the
`heater should be matched to the voltage of power
`source 121 so that the desired rate of heating is accom(cid:173)
`plished. At the same time, the resistance must be large
`compared to the internal resistance of power source 121 45
`to avoid excessive losses due to the internal resistance.
`Second, the surface area must be sufficiei:it to allow for
`support of the flavor-generating medium (with proper
`thickness and mass of the flavor-generating medium to
`alJow rapid heating), and to allow for generation or 50
`release of vapors or aerosols containing flavors or other
`volatile components. Third, the thermal conductivity,
`heat capacity, and heater mass must be such that the
`heat generated is conducted effectively to the flavor(cid:173)
`generating medium but not away from the heater to the 55
`surroundings, and such that excessive energy is not
`necessary to heat the heater itself.
`The contact resistance between the heater material
`and the contacts should be kept low. If necessary, suit(cid:173)
`able materials, such as tantalum, can be compounded or 60
`coated at the contact points to lower .contact resistance.
`Any materials added should be non-reactive at the oper(cid:173)
`ating temperatures.
`Heater/flavor/mouthpiece section 11 preferably
`would contain heater elements as described above 65
`coated with flavor-generating medium, all wrapped in a
`tube, which can be made of heavy paper, to allow it to
`be inserted by a consumer into section 12.
`
`5,322,075
`
`8
`Power source 121 preferably must be able to deliver
`sufficient energy to heat ten charges of flavor-generat(cid:173)
`ing medium, and still fit conveniently in the article.
`However, the energy to be delivered is not the only
`criterion, because the rate at which that energy is
`delivered-Le., the power-is also important. For ex(cid:173)
`ample, a conventional AAA-sized alkaline cell contains
`enough energy to heat several hundred charges of fla(cid:173)
`vor-generating medium, but it is not designed to deliver
`the necessary energy at a sufficient rate. On the other
`hand, nickel-cadmium (Ni-Cad) rechargeable batteries
`are capable of providing much greater power on dis(cid:173)
`charge. A preferred power source is four N50-AAA
`CADNICA nickel-cadmium cells produced by Sanyo
`Electric Company, Ltd., of Japan. These batteries pro(cid:173)
`vide 1.2-volts each, for a total of 4.8 volts when con(cid:173)
`nected in series. The four batteries together supply
`about 264 milliwatt-hours, which is sufficient to power
`at least one ten-puff article without recharging. Of
`course, other power sources, such as rechargeable lithi(cid:173)
`um-manganese dioxide batteries, can be used. Any of
`these types of batteries can be used in power source 121,
`but rechargeable batteries are preferred because of cost
`and disposal considerations associated with disposable
`batteries. In addition, if disposable batteries are used,
`section 12 must be able to be opened for replacement of
`the battery.
`If rechargeable batteries, as preferred, are used, a
`way must be provided to recharge them. A conven(cid:173)
`tional recharging unit (not shown) deriving power from
`a standard 120-volt AC wall outlet, or other sources
`such as an automobile electrical system or a separate
`portable power supply, can be used. The charge rate
`and controller circuitry must be tailored to the specific
`battery system to achieve optimal recharging. The re(cid:173)
`charging unit would typically have a socket into which
`the article, or at least section 12, would be inserted.
`The energy content of a battery in power source 121
`can be more fully exploited, despite the power or cur(cid:173)
`rent limitation of the battery, ifa capacitor is included in
`power source 121 as well. The discharge of the capaci(cid:173)
`tor can be used to power heater 110. Capacitors are
`capable of discharging more quickly than batteries, and
`can be charged between puffs, allowing the battery ·to
`discharge into the capacitor at a lower rate than if it
`were used to power heater 110 directly.
`Thus, the above-described smoking article uses a
`minimum number of electrical connectors to supply
`power selectively
`to
`individual
`flavor-generating
`charges, and has a heating array which can be manufac(cid:173)
`tured by mass-production techniques. One skilled in the
`art will appreciate that the present invention can be
`practiced by other than the described embodiments.
`The described embodiments are thus presented for pur(cid:173)
`poses of illustration, and not of limitation. The present
`invention is limited only by the claims which follow.
`We claim:
`1. A heater for an electric flavor-generating article,
`comprising:
`a flexible substrate;
`a plurality of connectors, deposited on the substrate,
`each connector having a free end and a connector
`end;
`a common, deposited on the substrate, having a free
`end and common ends;
`a plurality of heating elements, depositing on the
`substrate, each having a connector end and com(cid:173)
`mon end, the i;:onnector ends electrically con-
`
`Ex. 2007-0007
`
`

`

`5,322,075
`
`20
`
`30
`
`9
`nected to the connector ends of the connectors, the
`common ends electrically connected to the com(cid:173)
`mon ends of the common; and
`a plurality of electrical contacts, one of which is
`electrically connected to the free end of each of the 5
`connectors and the common.
`2. The heater of claim 1 further comprising a plurality
`of flavor charges, one of which is deposited on each of
`the heating elements.
`3. The heater of claim 2 wherein the flavor charges 10
`comprise a flavor-generating medium.
`4. The heater of claim 3 wherein the flavor-generat(cid:173)
`ing medium comprises tobacco.
`S. The heater of claims 3 or 4 wherein the flavor
`charges further comprise an aerosol-generating me- 15
`dium.
`6. The heater of claim S wherein the aerosol-generat(cid:173)
`ing medium comprises glycerine.
`7. The heater of claim S wherein the aerosol-generat-
`ing medium comprises water.
`8. The heater of claim 2 wherein the flavor charge
`comprises tobacco, glycerine, and calcium carbonate.
`9. The heater of claim 10 wherein the adhesive agent
`comprises a citrus pectin.
`10. The heater of c