Patent Description:
An electronic smoking device, such as an electronic cigarette (e-cigarette), typically has a housing accommodating an electric power source (e.g., a single use or rechargeable battery, electrical plug, or other power source), and an electrically operable atomizer. The atomizer vaporizes or atomizes liquid supplied from a reservoir and provides vaporized or atomized liquid as an aerosol. Control electronics control the activation of the atomizer. In some electronic cigarettes, an airflow sensor is provided within the electronic smoking device, which detects a user puffing on the device (e.g., by sensing an underpressure or an air flow pattern through the device). The airflow sensor indicates or signals the puff to the control electronics to power up the device and generate vapor. In other e-cigarettes, a switch is used to power up the e-cigarette to generate a puff of vapor.

Many electronic cigarettes deliver electronic cigarette juice from a reservoir to an atomizer via a combustible wick (via capillary effect); however, when the electronic cigarette is operated when the wick is inadequately saturated (e.g., when the atomizer's demand for juice exceeds the delivery rate of the wick), the wick may overheat and begin to combust. Combustion of the wick will result in an undesirable taste - thereby degrading the user's experience. Moreover, wick combustion may reduce the useable life of the electronic cigarette, and/or further reduce a maximum flow rate of the wick leading to subsequent wick overheating events and further device degradation. Different non-combustible wicks are disclosed in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>, wherein <CIT> describes an electronic cigarette which comprises the features mentioned in the preamble of the present claim <NUM>.

The foregoing discussion is intended only to illustrate the present field and should not be taken as a disavowal of claim scope.

Aspects of the present disclosure are directed to an electronic cigarette including an enhanced wick that delivers electronic cigarette juice from a reservoir to an atomizer for vaporization and inhalation by a user.

Aspects of the present disclosure are directed to an electronic cigarette including a tank, atomizer, and non-combustible wick. The tank contains eCig juice, and the atomizer includes a heating element. The atomizer vaporizes eCig juice into an airflow. The wick is positioned in fluid communication between the tank and the atomizer, and draws eCig juice from the tank and deposits the eCig juice on to the heating element. The wick is a conductive material with a non-conductive coating, the non-conductive coating of the wick configured and arranged to prevent current draw away from the heating element during vaporization of the eCig juice.

In accordance with various embodiments of the present disclosure an electronic cigarette is disclosed including a non-combustible wick that delivers electronic cigarette juice from a reservoir to an atomizer coil. In particular, embodiments of the present disclosure are directed to electronic cigarettes that incorporate one or more non-combustible wicks for use in vaporizing or aerosolizing a composition to provide a desired result to a user. In some embodiments, the electronic cigarette may achieve a user experience substantially similar to smoking a conventional cigarette, and/or to achieve delivery of an electronic cigarette juice to the atomizer at a rate that matches a vaporization rate of the atomizer.

In some embodiments, an electronic cigarette is disclosed including a wick formed of a rolled, stainless-steel mesh fluidly coupled between a reservoir and an atomizer coil. Some specific embodiments may include one or more rolled, stainless-steel mesh wicks, where each wick is either longitudinally coupled to the other wicks, or offset therefrom to provide distinct wicks for providing e-cig juice (e.g., one or more varieties of juice) to the same or different atomizer coils.

In specific embodiments, a conductive, mesh wick is disclosed including a non-conductive coating (on either the wick or the atomizer coil) to prevent current draw away from the atomizer coil during vaporization. Various non-conductive coatings are disclosed herein, including a diamond-like carbon, titanium oxide, polyamide, polyparaxylene, among others.

The characteristics, features and advantages of this invention and the manner in which they are obtained as described above, will become more apparent and be more clearly understood in connection with the following description of exemplary embodiments, which are explained with reference to the accompanying drawings.

In the drawings, the same element numbers indicate the same elements in each of the views:.

Aspects of the present disclosure are directed to an electronic cigarette including an enhanced wick that delivers electronic cigarette juice from a reservoir to an atomizer; wherein the enhanced wick includes desirable characteristics such as improved electronic cigarette juice flow rates, tolerance to overheating events, and/or an extended operational lifespan.

In accordance with one aspect of the present disclosure, an electronic cigarette is provided including a non-combustible wick that delivers electronic cigarette juice from a reservoir to an atomizer coil. In particular, embodiments of the present disclosure are directed to electronic cigarettes that incorporate one or more non-combustible wicks for use in vaporizing or aerosolizing a composition to provide a desired result to a user. In some embodiments, the electronic cigarette may achieve a user experience substantially similar to smoking a conventional cigarette, and/or to achieve delivery of an electronic cigarette juice to the atomizer at a rate that matches a vaporization rate of the atomizer.

In various embodiments, an electronic cigarette is disclosed including a wick formed of a rolled, stainless-steel mesh fluidly coupled between a reservoir and an atomizer coil. Some specific embodiments may include one or more rolled, stainless-steel mesh wicks, where each wick is either longitudinally coupled to the other wicks, or offset therefrom to provide distinct wicks for providing e-cig juice (e.g., one or more varieties of juice) to the same or different atomizer coils.

In specific embodiments, a conductive mesh wick is disclosed including a non-conductive coating (on either the wick or the atomizer coil) to prevent drawing current away from the atomizer coil during vaporization. This may be particularly desirable for electronic cigarettes that utilize resistance-based atomizer coil temperature control. Various non-conductive coatings are disclosed herein, including a diamond-like carbon, titanium oxide, polyamide, polyparaxylene, among others. Details of the various embodiments of the present disclosure are described below with specific reference to the figures.

Throughout the following, an electronic smoking device will be exemplarily described with reference to an e-cigarette. As is shown in <FIG>, an e-cigarette <NUM> typically has a housing comprising a cylindrical hollow tube having an end cap <NUM>. The cylindrical hollow tube may be a single-piece or a multiple-piece tube. In <FIG>, the cylindrical hollow tube is shown as a two-piece structure having a power supply portion <NUM> and an atomizer/liquid reservoir portion <NUM>. Together the power supply portion <NUM> and the atomizer/liquid reservoir portion <NUM> form a cylindrical tube which can be approximately the same size and shape as a conventional cigarette, typically about <NUM> with a <NUM> diameter, although lengths may range from <NUM> to <NUM> or <NUM>, and diameters from <NUM> to <NUM>.

The power supply portion <NUM> and atomizer/liquid reservoir portion <NUM> are typically made of metal (e.g., steel or aluminum, or of hardwearing plastic) and act together with the end cap <NUM> to provide a housing to contain the components of the e-cigarette <NUM>. The power supply portion <NUM> and the atomizer/liquid reservoir portion <NUM> may be configured to fit together by, for example, a friction push fit, a snap fit, a bayonet attachment, a magnetic fit, or screw threads. The end cap <NUM> is provided at the front end of the power supply portion <NUM>. The end cap <NUM> may be made from translucent plastic or other translucent material to allow a light-emitting diode (LED) <NUM> positioned near the end cap to emit light through the end cap. Alternatively, the end cap may be made of metal or other materials that do not allow light to pass.

An air inlet may be provided in the end cap, at the edge of the inlet next to the cylindrical hollow tube, anywhere along the length of the cylindrical hollow tube, or at the connection of the power supply portion <NUM> and the atomizer/liquid reservoir portion <NUM>. <FIG> shows a pair of air inlets <NUM> provided at the intersection between the power supply portion <NUM> and the atomizer/liquid reservoir portion <NUM>.

A power supply, preferably a battery <NUM>, the LED <NUM>, control electronics <NUM> and, optionally, an airflow sensor <NUM> are provided within the cylindrical hollow tube power supply portion <NUM>. The battery <NUM> is electrically connected to the control electronics <NUM>, which are electrically connected to the LED <NUM> and the airflow sensor <NUM>. In this example, the LED <NUM> is at the front end of the power supply portion <NUM>, adjacent to the end cap <NUM>; and the control electronics <NUM> and airflow sensor <NUM> are provided in the central cavity at the other end of the battery <NUM> adjacent the atomizer/liquid reservoir portion <NUM>.

The airflow sensor <NUM> acts as a puff detector, detecting a user puffing or sucking on the atomizer/liquid reservoir portion <NUM> of the e-cigarette <NUM>. The airflow sensor <NUM> can be any suitable sensor for detecting changes in airflow or air pressure, such as a microphone switch including a deformable membrane which is caused to move by variations in air pressure. Alternatively, the sensor may be, for example, a Hall element or an electromechanical sensor.

The control electronics <NUM> are also connected to an atomizer <NUM>. In the example shown, the atomizer <NUM> includes a heating coil <NUM> which is wrapped around a wick <NUM> extending across a central passage <NUM> of the atomizer/liquid reservoir portion <NUM>. The central passage <NUM> may, for example, be defined by one or more walls of the liquid reservoir and/or one or more walls of the atomizer/liquid reservoir portion <NUM> of the e-cigarette <NUM>. The coil <NUM> may be positioned anywhere in the atomizer <NUM> and may be transverse or parallel to a longitudinal axis of a cylindrical liquid reservoir <NUM>. The wick <NUM> and heating coil <NUM> do not completely block the central passage <NUM>. Rather an air gap is provided on either side of the heating coil <NUM> enabling air to flow past the heating coil <NUM> and the wick <NUM>. The atomizer may alternatively use other forms of heating elements, such as ceramic heaters, or fiber or mesh material heaters. Nonresistance heating elements such as sonic, piezo, and jet spray may also be used in the atomizer in place of the heating coil.

The central passage <NUM> is surrounded by the cylindrical liquid reservoir <NUM> with the ends of the wick <NUM> abutting or extending into the liquid reservoir <NUM>. The wick <NUM> may be a porous material such as a bundle of fiberglass fibers or cotton or bamboo yarn, with liquid in the liquid reservoir <NUM> drawn by capillary action from the ends of the wick <NUM> towards the central portion of the wick <NUM> encircled by the heating coil <NUM>.

The liquid reservoir <NUM> may alternatively include wadding (not shown in <FIG>) soaked in liquid which encircles the central passage <NUM> with the ends of the wick <NUM> abutting the wadding. In other embodiments, the liquid reservoir may comprise a toroidal cavity arranged to be filled with liquid and with the ends of the wick <NUM> extending into the toroidal cavity.

An air inhalation port <NUM> is provided at the back end of the atomizer/liquid reservoir portion <NUM> remote from the end cap <NUM>. The inhalation port <NUM> may be formed from the cylindrical hollow tube atomizer/liquid reservoir portion <NUM> or may be formed in an end cap.

In use, a user sucks on the e-cigarette <NUM>. This causes air to be drawn into the e-cigarette <NUM> via one or more air inlets, such as air inlets <NUM>, and to be drawn through the central passage <NUM> towards the air inhalation port <NUM>. The change in air pressure which arises is detected by the airflow sensor <NUM>, which generates an electrical signal that is passed to the control electronics <NUM>. In response to the signal, the control electronics <NUM> activate the heating coil <NUM>, which causes liquid present in the wick <NUM> to be vaporized creating an aerosol (which may comprise gaseous and liquid components) within the central passage <NUM>. As the user continues to suck on the e-cigarette <NUM>, this aerosol is drawn through the central passage <NUM> and inhaled by the user. At the same time, the control electronics <NUM> also activate the LED <NUM> causing the LED <NUM> to light up, which is visible via the translucent end cap <NUM>. Activation of the LED may mimic the appearance of a glowing ember at the end of a conventional cigarette. As liquid present in the wick <NUM> is converted into an aerosol, more liquid is drawn into the wick <NUM> from the liquid reservoir <NUM> by capillary action and thus is available to be converted into an aerosol through subsequent activation of the heating coil <NUM>.

Some e-cigarette are intended to be disposable and the electric power in the battery <NUM> is intended to be sufficient to vaporize the liquid contained within the liquid reservoir <NUM>, after which the e-cigarette <NUM> is thrown away. In other embodiments, the battery <NUM> is rechargeable and the liquid reservoir <NUM> is refillable. In the cases where the liquid reservoir <NUM> is a toroidal cavity, this may be achieved by refilling the liquid reservoir <NUM> via a refill port (not shown in <FIG>). In other embodiments, the atomizer/liquid reservoir portion <NUM> of the e-cigarette <NUM> is detachable from the power supply portion <NUM> and a new atomizer/liquid reservoir portion <NUM> can be fitted with a new liquid reservoir <NUM> thereby replenishing the supply of liquid. In some cases, replacing the liquid reservoir <NUM> may involve replacement of the heating coil <NUM> and the wick <NUM> along with the replacement of the liquid reservoir <NUM>. A replaceable unit comprising the atomizer <NUM> and the liquid reservoir <NUM> may be referred to as a cartomizer.

The new liquid reservoir may be in the form of a cartridge (not shown in <FIG>) defining a passage (or multiple passages) through which a user inhales aerosol. In other embodiments, the aerosol may flow around the exterior of the cartridge to the air inhalation port <NUM>.

Of course, in addition to the above description of the structure and function of a typical e-cigarette <NUM>, variations also exist. For example, the LED <NUM> may be omitted. The airflow sensor <NUM> may be placed, for example, adjacent to the end cap <NUM> rather than in the middle of the e-cigarette. The airflow sensor <NUM> may be replaced by, or supplemented with, a switch which enables a user to activate the e-cigarette manually rather than in response to the detection of a change in air flow or air pressure.

Different types of atomizers may be used. Thus, for example, the atomizer may have a heating coil in a cavity in the interior of a porous body soaked in liquid. In this design, aerosol is generated by evaporating the liquid within the porous body either by activation of the coil heating the porous body or alternatively by the heated air passing over or through the porous body. Alternatively the atomizer may use a piezoelectric atomizer to create an aerosol either in combination or in the absence of a heater.

<FIG> is a cross-sectional side view of a partial electronic cigarette assembly <NUM>. The partial electronic cigarette assembly <NUM> of <FIG> includes an atomizing chamber <NUM> which facilitates the flow of a user's draw around/through a heating coil <NUM>. Embodiments disclosed herein include a heating coil that is titanium or a composition of alloys including titanium. The heating coil <NUM> is wetted (using capillary action) with electronic cigarette juice via a metal, mesh wick <NUM> that draws the juice from a reservoir <NUM>. The coil <NUM> is fluidly coupled to the reservoir <NUM> containing the juice via the wick <NUM>. Specific/experimental embodiments disclosed herein include a stainless-steel, mesh wick rolled to form a mesh tube.

As shown in <FIG>, a wick <NUM> and heating coil <NUM> are coupled to one another to facilitate fluid communication, and transportation of electronic cigarette juice therebetween. Where both the wick <NUM> and heating coil <NUM> are conductive - e.g., where the heating coil is titanium and the wick is stainless steel, for example - the heating coil when driven by a current may short circuit to the wick negatively impacting vaporization of the juice on the coil, and draining battery life. Moreover, many electronic cigarettes now utilize a resistance measurement of the heating coil during vaporization to facilitate heater coil temperature control. Without isolating the heater coil from the wick, the resistance measurement across the coil would be inaccurate. Accordingly, it is desirable to have the heater coil and wick fluidly coupled, but electrically isolated from one another. To electrically isolate the heater coil from the wick, either the heater coil and/or wick may be coated with an insulative material. In various embodiments, the heating coil and/or wick may be coated with: diamond-like carbon (a class of amorphous carbon material that exhibits some of the typical properties of diamond), titanium dioxide, polyamides, polyparaxylene, among other electrically insulative materials. These coatings may be deposited using known techniques - for example, diamond-like carbon may be deposited using vapor deposition coating techniques.

In yet other embodiments, a heating coil and/or wick of an electronic cigarette may be insulated by forming an aluminum-oxide coating on an aluminum heating coil/wick, or forming a titanium-oxide coating on a titanium coil/wick. Both aluminum-oxide and titanium-oxide have electrically insulative characteristics.

Testing, the results of which are presented below in the Specific/Experimental Results section, have verified that steel, mesh wicks as disclosed herein are capable of juice flow rates desired for electronic cigarette applications. Preferred embodiments of the steel, mesh wicks may include: stainless-steel alloys, and/or titanium (or a metal alloy including titanium). Similarly, the heating coil material may include titanium (or a metal alloy including titanium). Mesh wicks and/or heating coils coated with diamond-like carbon may be preferred in some embodiments for diamond-like carbon's ability to maintain its electrically insulative characteristics in response to the temperature cycling of the heating coil. In yet other embodiments, the wick/coil may comprise copper or a metal alloy including copper.

A wick for an electronic cigarette application may be compromised from titanium. In one specific embodiment, the wick may be a titanium mesh made of titanium grade <NUM>, with a wire diameter of <NUM> (<NUM>" (<NUM> SWG)), and <NUM> holes-per-cm (<NUM> holes-per-inch). It has been discovered that smaller pore sizes within the mesh create increased capillary force. In yet another embodiment, the wick may be a titanium mesh made of titanium grade <NUM>, a wire diameter of <NUM> (<NUM>" (<NUM> SWG)), and <NUM> holes-per-cm (<NUM> holes-per-inch).

It has been discovered, through testing, that a stainless-steel, mesh wick with a diamond-like carbon insulative coating produces desirable capillary action for electronic cigarette applications.

To test the efficacy of a stainless-steel, mesh wick with diamond-like carbon coating in an electronic cigarette application, three test devices (see also, <FIG>) were built with a wick extending between an electronic cigarette juice reservoir and an atomizer coil (also referred to herein as a heating coil). As shown in <FIG>, below, the three test devices were able to meet the specifications for a typical dosage label claim deviation of ± <NUM>%. For the purposes of testing, the dosage label claim was <NUM> milligrams (mg). The maximum and minimum allowable dosages falling between approximately <NUM> and <NUM>. Each of the data points indicates an average device dose shot weight in milligrams- with each of the three groupings representative of a particular test device. The sample size for each of the test devices was <NUM> draws. While the device-to-device deviation was high -- ±<NUM>% Cp = <NUM> (where Cp is the process capability index) -- this deviation is likely associated with the devices being one-off prototypes.

<FIG> shows a normalised dose average shot weight distribution of the three test devices, where the intended dose is <NUM>. The ± <NUM>% limit is <NUM>, and <NUM>, respectively; while the ± <NUM>% limit is <NUM>, and <NUM>, respectively. The ±<NUM>% Cp = <NUM> - indicating a high likelihood that the test devices are capable of regularly producing shot weights within specification limits.

Claim 1:
An electronic cigarette (<NUM>) comprising:
a tank (<NUM>, <NUM>) configured and arranged to contain eCig juice;
an atomizer (<NUM>) including a heating element (<NUM>, <NUM>), (<NUM>), and configured and arranged to vaporize eCig juice into an airflow; and
a non-combustible wick (<NUM>, <NUM>) positioned in fluid communication between the tank (<NUM>, <NUM>) and the atomizer (<NUM>), and configured and arranged to draw eCig juice from the tank (<NUM>, <NUM>) and deposit the eCig juice on to the heating element (<NUM>, <NUM>),
characterized in that
the wick (<NUM>, <NUM>) is a conductive material with a non-conductive coating, the non-conductive coating of the wick (<NUM>, <NUM>) configured and arranged to prevent current draw away from the heating element (<NUM>, <NUM>) during vaporization of the eCig juice.