United States Patent c191
`Deevi et al.
`
`[54] ELECTRICALLY-POWERED LINEAR
`HEATING ELEME1''T
`
`[75]
`
`Inventors: Seetharama C. Dee'ri, Midlothian;
`Francis M. Sprinkel, Glen Allen,
`both of Va.
`
`[22] Filed:
`
`[73] Assignee: Philip Morris Incorporated, New
`York, N.Y.
`[21] Appl. No.: 444,569
`Dec. 1, 1989
`[51] Int. Cl.5 ............................................... HOSB 3/26
`[52] U.S. Cl . .................................... 392/390; 392/395;
`392/404
`[58] Field of Search ................................ 219/271-276,
`219/543;338/306-309,292,293; 392/390,395,
`403,404
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`1,771,366 7/1930 Wyss et al. .
`1,968,509 7/1934 Tiffany .
`2,057,353 10/1936 Whittemore, Jr ..
`2,104,266 1/1938 McCormick .
`2,442,004 5/1948 Hayward-Butt .................... 128/200
`2,974,669 3/1961 Ellis ..................................... 131/172
`3,200.819 8/1965 Gilbert ................................ 128/208
`3,363,633 1/1968 Weber ................................. 131/178
`3,402,723 9/1968 Hu ....................................... 131/185
`3,482,580 12/1969 Hollabaugh ........................ , 131/178
`3,496,336 2/1970. Hingorany .......................... 219/464
`3,591,753 7/1971 Gartner ............................... 219/464
`3,804,100 4/1974 Fariello ............................... 131/173
`3,889,690 6/1975 Guarnieri ............................ 131/185
`4,016,061 4/1977 Wasa et al ....................... 204/192 F
`4,068,672 1/1978 Guerra ............................ 131/170 A
`4,077,784 3/1978 Vayrynen ............................. 55/146
`4,131,119 12/1978 Blasutti ................................ 131/187
`4,141,369 2/1979 Burruss ........................... 131/171 A
`4,164,230 8/1979 Pearlman ........................ 131/171 R
`4,193,411 3/1980 Faris et al. ...................... 131/171 R
`4,194,108 3/1980 Nakajima ............................ 219/543
`4,203,025 5/1980 Nakatani ............................. 219/543
`4,215,708 8/1980 Bron ................................ 131/262 B
`4,219,032 8/1980 Tabaunik et al. .............. 131/170 A
`4,246,913 1/1981 Ogden et al .................... 131/171 A
`4,256,945 3/1981 Caner et al. ..................... 219/10.75
`
`11111111111111111 IIIII lllll lllll 1111111111111111111111111111111111111111III
`US005093894A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,093,894
`Mar. 3, 1992
`
`4,259,564 3/1981 Ohkubo ............................... 219/543
`4,259,970 4/1981 Green, Jr ............................ 131/330
`4,303,083 12/1981 Burruss, Jr .......................... 131/271
`4,393,884 7 /1983 Jacobs ................................. 131/273
`4,431,903 2/1984 Riccio ................................. 219/238
`4,436,100 3/1984 Green, Jr ............................ 131/330
`4,463,247 7/1984 Lawrence et al ................... 219/236
`(List continued on next page.)
`
`FOREIGN PATENT DOCUMENTS
`1202378 3/1986 Canada .
`87/104459 2/1988 China .
`0295122 12/1988 European Pat. Off ..
`0358002 3/1990 European Pat. Off ..
`0358114 3/1990 European Pat. Off ..
`3640917Al 8/1988 Fed. Rep. of Germany.
`3735704AI 5/1989 Fed. Rep. of Germany .
`61-68061 4/1986 Japan .
`WO86/02528 4/1986 PCT Int'! Appl. .
`2132539 7/1984 United Kingdom .
`2148079 5/19.85 United Kingdom .
`2148676 5/1985 United Kingdom .
`Primary Examiner-Teresa J. Walberg
`Attorney, Agent, or Firm-Charles B. Smith
`
`ABSTRACT
`[57]
`A heating element for use within a smoking device
`which is intended to be held in the lips of a consumer,
`and which without burning, heats a flavor-generating
`medium within the device to produce an aerosol, vapor,
`or flavor, which the consumer may inhale. More partic(cid:173)
`ularly, an electrically-powered heating element having
`a plurality of discrete resistive heating segments, only
`one of which is active at any given time. In a preferred
`embodiment, the heating element is contained within
`the device so that the individual heating segments of the
`element are adjacent to a flavor-generating medium. As
`each segment of the heating element is provided with
`power, the flavor-generating medium adjacent to that
`segment is heated, but is not burned. This heating causes
`the flavor-generating medium to produce a flavor, aero(cid:173)
`sol, or vapor, which the consumer of the device may
`inhale.
`
`29 Claims, S Drawing Sheets
`
`Ex. 2005-0001
`
`

`

`5,093,894
`
`Page 2
`
`U.S. PATENT DOCUMENTS
`4,562,337 12/1985 Lawrence ........................... 219/421
`4,570,646 2/1986 Herron ................................ 131/185
`4,580,583 4/1986 Green, Jr ............................ 131/330
`4,621,649 11/1986 Osterrath ............................ 131/185
`4,623,401 11/1986 Derbyshire et al. .................. 148/13
`4,629,604 12/1986 Spector ............................... 219/275
`4,637,407 1/1987 Bonanno et al. .................... 131/175
`4,659,912 4/1987 Derbyshire ......................... 219/535
`
`4,686,353 8/1987 Spector ............................... 219/275
`. 4,692,590 9/1987 Spector ............................... 219/275
`4,735,217 4/1988 Gerth et al. ......................... 131/273
`4,771,796 9/1988 Myer ................................... 131/273
`4,776,353 10/1988 Lilja et al. ........................... 131/297
`4,837,421 6/1989 Luthy .
`4,846,199 7/1989 Rose .................................... 131/329
`4,848,376 7/1989 Lilja et al. .......... , ................ 131/352
`4,874,924 10/1989 Yamamoto et al. .
`4,877,989 10/1989 Drews et al ........................ 310/323
`
`Ex. 2005-0002
`
`

`

`U.S. Patent
`
`Mar. 3, 1992
`
`Sheet 1 of S
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`5,093,894
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`Ex. 2005-0003
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`

`V.s. Patent
`
`Mar. 3, 1992
`
`Sheet 2 of 5
`Sheet 2 of S
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`5,093,894
`59093,894
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`Ex. 2005-0004
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`Ex. 2005-0004
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`

`

`U.S. Patent
`US. Patent
`
`Mar. 3, 1992
`Mar. 3, 1992
`
`Sheet 3 of 5
`Sheet 3 of S
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`5,093,894
`5,093,894
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`F:!9.SB.
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`
`
`Ex. 2005-0005
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`Ex. 2005-0005
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`

`

`U.S. Patent
`US. Patent
`
`Mar. 3, 1992
`Mar. 3, 1992
`
`Sheet 4 of 5
`Sheet 4 of 5
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`5,093,894
`5,093,894
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`12
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`
`
`7
`
`Ex. 2005-0006
`
`Ex. 2005-0006
`
`

`

`U.S. Patent
`
`Mar. 3, 1992
`
`Sheet S of S
`
`5,093,894
`
`F!3.BA.
`4
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`I
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`
`Ex. 2005-0007
`
`

`

`ELECTRICALLY-POWERED LINEAR HEATING
`ELEMENT
`
`BACKGROUND OF THE INVENTION
`The present invention provides a heating element for
`use within a smoking device which is intended to beheld
`in the lips ofa consumer, and in which burning does not
`take place. More particularly, this invention relates to
`an electrically-powered heating element having a plu- IO
`rality of discrete electrically resistive heating segments,
`only one of which is active at any given time. The ele(cid:173)
`ment is intended to heat a flavor-generating medium,
`which is contained within the device, without burning.
`As a result of this heating, the flavor-generating me- 15
`dium produces a flavored aerosol or vapor which the
`consumer may inhale.
`Previously known conventional smoking devices
`deliver flavor and aroma to the user as a result of com(cid:173)
`bustion. During combustion, a mass of combustible 20
`material, primarily tobacco, is oxidized as the result of
`applied heat (typical combustion temperatures in a con(cid:173)
`ventional cigarette are in excess of 800° C. during puff(cid:173)
`ing). During this heating, inefficient oxidation of the
`combustible material takes place and yields various 25
`distillation and pyrolysis products. As these products
`are drawn through the body of the smoking device
`toward the mouth of the user, they cool and condense
`to form an aerosol or vapor which gives the consumer
`the flavor and aroma associated with smoking.
`Such conventional smoking devices have various
`perceived drawbacks associated with them. Among
`these is the production of sidestream smoke which may
`be objectionable to non-smokers in the vicinity of the
`consumer of the device.
`An alternative to conventional smoking devices are
`those in which the combustible material itself does not
`directly provide the flavorants to the aerosol or vapor
`inhaled by the user. In these devices, a combustible
`heating element, typically carbonaceous in nature, is 40
`ignited and used to heat air which is then drawn
`through a zone which contains some means for produc(cid:173)
`ing a flavored aerosol or vapor upon interaction with
`the heated air. While this type of smoking device pro(cid:173)
`duces little or no sidestream smoke, it still shares some 45
`characteristics with conventional cigarettes which are
`perceived as undesirable.
`In both the conventional and carbon element heated
`smoking devices described above combustion takes
`place during their use. This process naturally gives rise 50
`to many by-products as the material supporting the
`combustion breaks down and interacts with the sur(cid:173)
`rounding atmosphere.
`Additionally, the combustion process which takes
`place in both of the aforementioned types of smoking 55
`devices cannot be easily suspended by the user in order
`to allow storage of the smoking device for later con(cid:173)
`sumption. Obviously a conventional cigarette may be
`extinguished prior to its being smoked to completion,
`but if the user wishes to save the remaining portion of 60
`the cigarette for later use, he is faced with the problem
`of storing a relatively small, ash laden paper tube; con(cid:173)
`venient storage for such an item would most likely not
`be readily available. Users of the carbon element heated
`combustible smoking devices do not even have the 65
`option of extinguishing the device after it has been ig(cid:173)
`nited, as the heating element contained within such
`devices is typically inaccessible to the user. Once lit,
`
`1
`
`5,093,894
`
`2
`such carbon element smoking devices must be smoked
`to completion or discarded prior to completion while
`still burning.
`Accordingly, it is the object of the present invention
`5 to provide for an electrically-powered heating element
`for use within an article intended to be held in the lips of
`a consumer, which will heat a flavor-generating me(cid:173)
`dium without burning. This flavor-generating medium,
`as a result of the heating, would produce a flavored
`aerosol or vapor which the consumer could then inhale.
`Furthermore, the heating element disclosed is config-
`ured so as to allow the consumer to operate the device
`in a puff by puff manner, with the option of suspending
`the operation of the device after any given puff, prior to
`the depletion of the device. The device could then be
`conveniently stored until some later time at which the
`consumer wished to resume operation.
`
`SUMMARY OF THE INVENTION
`This invention provides an electrically resistive linear
`heating element for use in a non-burning device. In a
`preferred embodiment the element consists of three
`component parts, namely a base region, an insulating
`region, and a heating region. Each heating region may
`consist of a single resistive heating segment, or be_ com(cid:173)
`prised of a plurality of electrically discrete resistive
`heating segments. In the former case, a plurality of
`heating elements would be used within a single device;
`30 in the latter, only a single heating element would be
`required.
`In operation, the heating element would be contained
`within a device intended to be held in the lips of a con(cid:173)
`sumer, and the resistive heating segments would be
`35 switchably connected to an electrical power source.
`Each element would be positioned within the device so
`that when power is supplied to a given resistive heating
`segment the heat produced by that segment would be
`transferred to a portion of a flavor-generating medium,
`thus heating the medium. When so heated, this flavor(cid:173)
`generating medium would provide a flavored aerosol or
`vapor which the user of the device could inhale. The
`supply of electrical power to a given heating segment
`would be coincident with the user puffing the device.
`With each puff, a different heating segment within the
`device would be supplied with power, until all the seg-
`ments within the device had been supplied with power
`once; at this point the device would be depleted. This
`switching of power between segments could be directly
`controlled by the user or triggered by control circuitry.
`Smoking devices employing heating elements made
`in accordance with the principles of the present inven(cid:173)
`tion have certain advantages over combustion-type
`smoking devices. For example, such non-burning smok(cid:173)
`ing devices give the user the sensation and flavor of
`smoking without actually creating some of the smoke
`components associated with combustion. This may
`allow the consumers of non-burning devices to enjoy
`the use of this device in areas where conventional smok(cid:173)
`ing would be prohibited; such areas could include res-
`taurants, offices, and commercial aircraft.
`In addition, the elimination of burning from the pro(cid:173)
`cess also prevents the creation of many of the by-pro(cid:173)
`ducts of burning. Because the heating element of the
`present invention never reaches a temperature which is
`sufficient to induce burning, such by-products are never
`produced.
`
`Ex. 2005-0008
`
`

`

`5,093,894
`
`4
`FIG. 6B is a perspective view of the embodiment of
`the electrically-powered heating element of FIG. 6A;
`FIG. 7A is a partial cutaway perspective view of a
`portion of a smoking device showing the electrically(cid:173)
`powered heating element of FIG. 6A positioned within;
`FIG. 7B is a front view of the embodiment of the
`electrically-powered heating element of FIG. 6A posi(cid:173)
`tioned within a device;
`FIG. SA is a side view of a two component embodi(cid:173)
`ment of the electrically-powered heating element hav(cid:173)
`ing a plurality of individual heating segments; and
`FIG. SB is a perspective view of the embodiment of
`the electrically-powered heating element of FIG. SA.
`
`3
`A further advantage of this electrically-powered
`heating element is that it is very efficient in its utilization
`of electrical energy in heating the flavor-generating
`medium which provides the consumer with a flavored
`aerosol or vapor. The heating element is intended to 5
`receive electrical energy only during those periods
`when the device is being puffed, and only one heating
`segment is to be active during any given puff. This
`economy of energy consumption allows for a reduction
`in the amount of space which must be occupied by the 10
`element's power source, thus enabling a device in which
`the present invention is employed to be contained in a
`package which is comparable in size and shape to a
`conventional cigarette.
`Moreover, the controllable nature of this invention 15
`allows the consumer to stop consuming the article prior
`to operating it to completion, and to continue consum(cid:173)
`ing the article at some later time. Also, as only one
`heating segment within the device is active at any given
`time, the heat produced by the device at any given time 20
`remains relatively low. This low heat level allows the
`consumer to store a previously active, but unfinished
`device for later use, without concern as to the device's
`elevated temperature; the device may be stored almost
`immediately after it was last puffed. Such intermittent
`use and convenient storage is not practical with burn(cid:173)
`ing-type smoking devices.
`Furthermore, the nature of the construction of the
`heating element lends itself to economical, continuous 30
`production using simple manufacturing methods.
`
`25
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`A preferred embodiment of the linear heating ele(cid:173)
`ment is shown in FIGS. IA and IB. It comprises three
`planar component regions; namely a base region 1, an
`insulating region 2, and a heating region 3.
`In this three component embodiment the base region
`I provides for the physical support of the insulating and
`heating regions. The base region in this particular em(cid:173)
`bodiment includes a metallic tape, such as aluminum foil
`tape. The tape, while being rigid enough to physically
`support the insulating and heating regions, can be flexi-
`ble enough to facilitate easy handling and resist fractur(cid:173)
`ing during the manufacturing process. The metallic
`nature of the base region provides for the thermal stabil(cid:173)
`ity of the heating element as most metals will not sub(cid:173)
`stantially deform or become chemically reactive at tem-
`peratures such as those encountered when the heating
`element is active.
`Adjoining the base region, and physically separating
`35 it from the heating region, is the insulating region 2.
`This insulating region must have a sufficiently low elec(cid:173)
`trical conductivity so as to isolate the electrically resis(cid:173)
`tive heating region from the electrically conductive
`metallic base region. Like the base region, the insulating
`region must be thermally stable at the elevated tempera(cid:173)
`tures which the active heating element would produce.
`In addition, this region should have a sufficiently high
`heat capacity so as to sink and buffer undesirable heat
`pulses which may be inadvertently produced by the
`heating region. This buffering prevents the flavor(cid:173)
`generating medium from burning, which could detri-
`mentally affect flavor and aerosol or vapor delivery.
`The insulating region can be fabricated using metallic
`oxidies, metallic nitrides, metallic carbides, metallic
`silicides, nonmetallic oxides, nonmetallic nitrides, non(cid:173)
`metallic carbides, nonmetallic silicides, metallic car-
`bonitride, an inter-metallic compound, a cermet, or an
`alloy of more than one metal. This region can also be
`composed of a combination of the elements of the previ-
`55 ously mentioned list, to achieve the non-conducting,
`thermally-insulating, and structural properties needed
`for operation.
`Such materials may be fabricated separately and then
`joined with the base material or applied to the base
`60 materials as a fabrication step: by a coating process, a
`dip, mechanical pressing, slip casting, tape casting, ex(cid:173)
`trusion, chemical vapor deposition, thermal spraying,
`plasma spraying, or any other method of pyrolytical or
`chemical deposition.
`Situated adjacent to the insulating region and oppo(cid:173)
`site the base region is the heating region 3. In this partic(cid:173)
`ular embodiment the heating region is not continuous in
`nature, rather it is comprised of a plurality of electri-
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The above and other objects and advantages of this
`invention will be apparent on consideration of the fol(cid:173)
`lowing detailed description, taken in conjunction with
`the accompanying drawings, in which like reference
`characters refer to like parts throughout, and in which:
`FIG. IA is a side view of a three component embodi(cid:173)
`ment of the electrically-powered heating element hav- 40
`ing a plurality of individual heating segments;
`FIG. 1B is a perspective view of the embodiment of
`the electrically-powered heating element of FIG. lA;
`FIG. IC is a perspective view of a portion of the
`heating element of FIG. IA showing the connection of 45
`the individual heating segments to an electrical power
`source and switching means;
`FIG. 2A is a side view of a five component embodi(cid:173)
`ment of the electrically-powered heating element hav-
`ing a plurality of individual heating segments;
`FIG. 2B is a perspective view of the embodiment of
`the electrically-powered heating element of FIG. 2A;
`FIG. 3 is a partial cutaway perspective view of a the
`embodiment of the electrically-powered heating ele(cid:173)
`ment of FIG. IA, and an electrical power source and
`switching means positioned within a device;
`FIG. 4 is a partial cutaway perspective view of the
`embodiment of the electrically-powered heating ele(cid:173)
`ment of FIG. 2A, and an electrical power source and
`switching means positioned within a device;
`FIG. SA is a side view of a three component electri(cid:173)
`cally-powered heating element having a singular heat(cid:173)
`ing segment;
`FIG. SB is a perspective view of the embodiment of
`the electrically-powered heating element of FIG. SA; 65
`FIG. 6A is a front view of an alternate embodiment
`of a three component electrically-powered heating ele(cid:173)
`ment having a singular heating segment;
`
`so
`
`Ex. 2005-0009
`
`

`

`5,093,894
`
`s
`cally discrete resistive heating segments 4. Each of the
`heating segments is situated so that it may be switchably
`connected to a power source in a manner which would
`allow current from the power source to be directed
`through a given segment thereby heating it. This 5
`switching of power to a particular segment could be
`directly controlled by the user or triggered by control
`circuitry. As illustrated in FIG. IC, the connection
`between the heating segments 4 and an electrical power
`source and switching means 5 (such means includes any 10
`control circuitry) could be facilitated by conventional
`wires 6 attached to each of the segments. The resistivity
`of an individual heating segment must be such that
`when current flows through a given segment a tempera(cid:173)
`ture sufficient to induce the flavor-generating medium 15
`to produce an aerosol or flavor or vapor is achieved;
`typically this temperature is between about l()()° C. and
`600° C., preferably between about 250° -500° C. and
`most preferably between about 350° -450° C. However,
`the resistivity cannot be so high as to impede the heat- 20
`ing of the flavor-generating medium, using multiple
`batteries. Nor can it be so low that the power consump(cid:173)
`tion requirement of the segment exceeds the capacity of
`the source. Typically, heating segments having resis(cid:173)
`tances between 0.2 and 20.0 ohms, and preferably be- 25
`tween 0.5 and 1.5 ohms, and most preferably between
`0.8 and 1.2 ohms, can achieve such operating tempera(cid:173)
`tures when connected across a potential of between 2.4
`and 9.6 volts.
`Throughout their range of operating temperatures, 30
`the heating segments must be chemically non-reactive
`with the flavor-generating medium being heated, so as
`not to adversely affect the flavor or content of the aero-
`sol or vapor produced by the flavor-generating me(cid:173)
`dium. The heating segments may be composed of car- 35
`hon, graphite, carbon/graphite composites, metallic and
`non-metallic carbides, nitrides, silicides, inter-metallic
`compounds, cermets, alloys of metals, or Rare Earth
`and refractory metal foils, and may be deposited using
`any of the methods which were previously specified as 40
`being suitable for the deposition of the insulating region.
`Alternatively, they may be fabricated separately and
`laminated or otherwise assembled. Different materials
`can be mixed to achieve the desired properties of resis(cid:173)
`tivity, mass, thermal conductivity and surface proper- 45
`ties. The preferred materials are graphite-carbon com(cid:173)
`posites.
`An additional preferred embodiment is shown in
`FIGS. 2A and 2B. A base region 1 is adjoined on two
`opposing sides by insulating regions 2, and a heating 50
`region 3 is situated adjacent to each of these insulating
`regions and opposite the base region. As in the previ(cid:173)
`ously described embodiment, each of the heating re(cid:173)
`gions is comprised of a plurality of electrically-discrete
`resistive heating segments 4. Each of these component 55
`regions is similar in composition, fabrication, and physi(cid:173)
`cal characteristics to the like named regions which were
`disclosed in the description of the first embodiment.
`The operation of this five component embodiment of
`the heating element is primarily the same as that of the 60
`three component embodiment. The heating segments
`would be connected to a power source and switching
`means by conventional wires, as in the previously de(cid:173)
`scribed three-component embodiment, with the excep(cid:173)
`tion that in the instant embodiment the heating seg- 65
`ments would be switchably connected to a power
`source and switching means in a manner where two
`segments would be active at a given time. During a puff,
`
`6
`power would be supplied to a pair of heating segments,
`one in each of the two heating regions. Such a two(cid:173)
`sided heating element would increase the surface area of
`flavor-generating medium adjacent to an active heating
`segment during a puff.
`All of the embodiments of the heating element which
`have been heretofore described may be situated within
`a cylindrical device having an outside diameter of be(cid:173)
`tween 6 and 18 millimeters. As shown in FIG. 3, the
`heating element 7 is mounted axially within the body 8
`of a device in such a manner as to allow the consumer
`of the device to draw air from the far end 9 of the de(cid:173)
`vice, causing the air to pass over the element, and exit at
`the mouthpiece end 10 of the device. The power source
`and switching means 5 for the element is shown to be
`attached to the interior wall of the device in a manner
`which would not interfere with the flow of air through
`the device (for the sake of visual clarity, the wiring
`connecting the power source and switching means and
`the individual heating segments is not shown).
`FIG. 4 shows a five component segmented heating
`element 7 similarly situated within a smoking device 8.
`Again the consumer may draw air from the far end 9 of
`the device, past the power source and switching means
`5, over the element 7, and out of the mouthpiece end 10
`of the device (as in FIG. 3, the wiring connecting the
`power source and switching means and the individual
`heating segments is not shown). In an alternative em(cid:173)
`bodiment, air can also enter through the outside wall of
`the device, pass around the heater array, and then exit
`the mouth end 10.
`Although all regions have been shown in the figures
`as being planar and rectangular, they may also be curled
`or spiral, to achieve the required surface area for heat(cid:173)
`ing within the size of the device.
`Yet another preferred embodiment of the linear heat(cid:173)
`ing element is shown in FIGS. SA and SB. It includes
`three planar component regions; namely a base region 1,
`an insulating region 2, and a heating region 3. In this
`three-component embodiment, the base region 1, the
`insulating region 2, and the heating region 3 are similar
`in composition and function to the like-named regions in
`the previously described embodiments. However, the
`heating region is comprised of a singular, continuous,
`electrically resistive area, as opposed to a plurality of
`discrete resistive heating segments.
`FIGS. 6A and 6B show an alternative preferred em(cid:173)
`bodiment of the heating element, which is identical in
`all respects to the above described embodiment, except
`that the component regions are arched rather than pla(cid:173)
`nar in nature.
`The embodiments of the heating element which have
`a single resistive heating segment may be employed
`within a device which is similar in size and shape to a
`conventional cigarette. As pictured in FIG. 7A, a plu(cid:173)
`rality of these heating elements 7 are situated radially
`within the body of device 8 in such a manner as to allow
`the user of the device to draw air from the far end of the
`device, or through the exterior wall, into channels 11,
`which allow the air to pass over the elements before
`exiting at the mouthpiece end of the device. The power
`source and switching means for the element could be
`housed anywhere within the central core 12 of the de(cid:173)
`vice, without regard to obstructing the air flow through
`the device (such flow is facilitated by the channels 11
`within the body of the device 8). FIG. 7B is cross-sec(cid:173)
`tional view of such a smoking device showing the base
`region 1, insulating region 2 and heating region 3 of the
`
`Ex. 2005-0010
`
`

`

`5,093,894
`
`7
`heating elements 7, which are radially arranged within
`the body of the device 8.
`In all of the previously described embodiments, the
`base region has been a metallic tape; however, in any of
`the above embodiments, this region could alternately be 5
`comprised of a foam mat, or a woven or non-woven
`fiber mat. Materials such as graphite, carbon, a metallic
`carbonitride, silicon dioxide, silicon carbide, or alumina
`could be used to fabricate the base region mat. The mat,
`while being rigid enough to physically support the heat- 10
`ing and insulating regions, can be flexible enough to
`facilitate easy handling and resist fracturing during the
`manufacturing process. In addition, the base region mat
`must be thermally stable at high temperatures to ensure
`that it will not react with the neighboring heating re- 15
`gion or decompose at elevated temperatures produced
`when the heating element is active.
`When employed as a base region, a mat provides
`certain advantages over a solid tape. Unlike a tape, the
`mat is comprised of either a large number of individual 20
`fibers (with voids existing between those fibers), or a
`foam having many minute voids located throughout its
`structure. By impregnating the mat with a flavor(cid:173)
`generating medium, thus filling the voids in that mat
`with the flavor-generating medium, a relatively large 25
`amount of the flavor-generating medium may be
`brought within close proximity of the resistive heating
`segments of the heating element. Such an arrangement
`would promote the efficient heating of the flavor(cid:173)
`generating medium. The fibers or foam structure of the 30
`base region would provide an effective means of chan(cid:173)
`neling the heat produced by the resistive heating seg(cid:173)
`ments to the flavor-generating medium, while at the
`same time sinking some of the heat so as to buffer the
`flavor-generating medium from any undesirable heat 35
`pulses, which might otherwise result in the burning of
`the flavor-generating medium.
`In any of the above described embodiments, regard(cid:173)
`less of whether the base region was comprised of a tape
`or a mat, the insulating region could be eliminated if the 40
`base region were to be fabricated from a material which
`would permit the heating segments to be placed in di(cid:173)
`rect contact with it. That is to say, the base material
`would have to remain chemically and physically stable
`when directly exposed to the elevated temperatures of 45
`the active heating segments. In addition, such a base
`material would have to have a low enough electrical
`conductivity so as to insure that the individual heating
`segments remained electrically isolated from each
`other. The base region material would also have to 50
`exhibit a sufficiently high heat capacity so as to sink and
`buffer undesirable heat pulses which may be inadver(cid:173)
`tently produced by the heating region. However, it
`must not be so high as to impede the heating of the
`flavor-generating medium to a temperature sufficient to 55
`allow the production of an aerosol or vapor. This buff(cid:173)
`ering would protect the flavor-generating medium from
`burning, which could detrimentally affect flavor and
`aerosol or vapor delivery. Alumina and other ceramic
`materials could be used to fabricate such a base region. 60
`Metallic and nonmetallic carbides, nitrides, silicides,
`oxides, metallic carbonitrides,
`inter-metallic com(cid:173)
`pounds, and cermets (ceramic/metallic composites) can
`also be used to produce the mat material and to tailor
`the specific properties or resistivities, heat capacity, 65
`mass, surface area and texture for optimum perfor(cid:173)
`mance. An example of such an embodiment is illustrated
`in FIGS. BA and BB. The heating region 3, composed of
`
`8
`a plurality of discrete resistive heating segments 4, is
`adjacent to the base region 1.
`Furthermore, in any of the above described embodi(cid:173)
`ments, an additional protective region could be depos(cid:173)
`ited which would envelop the heating region. Such a
`region would only be needed when the material which
`formed the heating region proved to be chemically
`reactive with the flavor-generating medium to be
`heated. This protective region would physically isolate
`the heating region from the flavor-generating medium,
`and would prevent any undesirable effects upon the
`flavor or content of the aerosol or vapor produced by
`the flavor-generating medium during heating. Natu(cid:173)
`rally, the protec