Electronic cigarette with mass air flow sensor

In accordance with one aspect of the present invention there is provided an electronic smoking device comprising a flow channel and an atomizer. The flow channel can comprise an incoming airflow opening, an incoming airflow pathway, a sensor assembly, and an outgoing airflow opening. The atomizer can be fluidly coupled to the flow channel. The flow channel can be configured to direct an airflow from the incoming airflow opening, through the incoming airflow pathway, over the sensor assembly, and through the outgoing airflow opening. The electronic smoking device can further be configured to pass the airflow over the atomizer.

FIELD OF INVENTION

The present invention relates generally to electronic smoking devices and in particular electronic cigarettes.

BACKGROUND OF THE INVENTION

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 under-pressure or an airflow 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.

In prior art eCigs, the pressure sensor is configured to sense a user's draw on the eCig and transmit an activation signal to the heating coil to vaporize the liquid solution. However, these pressure sensors can be large and costly.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention there is provided an electronic smoking device comprising a flow channel and an atomizer. The flow channel can comprise an incoming airflow opening, an incoming airflow pathway, a sensor assembly, and an outgoing airflow opening. The atomizer can be fluidly coupled to the flow channel. The flow channel can be configured to direct an airflow from the incoming airflow opening, through the incoming airflow pathway, over the sensor assembly, and through the outgoing airflow opening. The electronic smoking device can further be configured to pass the airflow, at least in part, over the atomizer.

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.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Throughout the following, an electronic smoking device will be exemplarily described with reference to an e-cigarette. As is shown inFIG. 1, an e-cigarette10typically has a housing comprising a cylindrical hollow tube having an end cap12. The cylindrical hollow tube may be a single-piece or a multiple-piece tube. InFIG. 1, the cylindrical hollow tube is shown as a two-piece structure having a power supply portion14and an atomizer/liquid reservoir portion16. Together the power supply portion14and the atomizer/liquid reservoir portion16form a cylindrical tube which can be approximately the same size and shape as a conventional cigarette, typically about 100 mm with a 7.5 mm diameter, although lengths may range from 70 to 150 or 180 mm, and diameters from 5 to 28 mm.

The power supply portion14and atomizer/liquid reservoir portion16are typically made of metal (e.g., steel or aluminum, or of hardwearing plastic) and act together with the end cap12to provide a housing to contain the components of the e-cigarette10. The power supply portion14and the atomizer/liquid reservoir portion16may 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 cap12is provided at the front end of the power supply portion14. The end cap12may be made from translucent plastic or other translucent material to allow a light-emitting diode (LED)18positioned 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 portion14and the atomizer/liquid reservoir portion16.FIG. 1shows a pair of air inlets20provided at the intersection between the power supply portion14and the atomizer/liquid reservoir portion16.

A power supply, preferably a battery22, the LED18, control electronics24and, optionally, an airflow sensor26are provided within the cylindrical hollow tube power supply portion14. The battery22is electrically connected to the control electronics24, which are electrically connected to the LED18and the airflow sensor26. In this example, the LED18is at the front end of the power supply portion14, adjacent to the end cap12; and the control electronics24and airflow sensor26are provided in the central cavity at the other end of the battery22adjacent the atomizer/liquid reservoir portion16.

The airflow sensor26acts as a puff detector, detecting a user puffing or sucking on the atomizer/liquid reservoir portion16of the e-cigarette10. The airflow sensor26can 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 electro-mechanical sensor.

The control electronics24are also connected to an atomizer28. In the example shown, the atomizer28includes a heating coil30which is wrapped around a wick32extending across a central passage34of the atomizer/liquid reservoir portion16. The central passage34may, for example, be defined by one or more walls of the liquid reservoir and/or one or more walls of the atomizer/liquid reservoir portion16of the e-cigarette10. The coil30may be positioned anywhere in the atomizer28and may be transverse or parallel to a longitudinal axis of a cylindrical liquid reservoir36. The wick32and heating coil30do not completely block the central passage34. Rather an air gap is provided on either side of the heating coil30enabling air to flow past the heating coil30and the wick32. 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 passage34is surrounded by the cylindrical liquid reservoir36with the ends of the wick32abutting or extending into the liquid reservoir36. The wick32may be a porous material such as a bundle of fiberglass fibers or cotton or bamboo yarn, with liquid in the liquid reservoir36drawn by capillary action from the ends of the wick32towards the central portion of the wick32encircled by the heating coil30.

The liquid reservoir36may alternatively include wadding (not shown inFIG. 1) soaked in liquid which encircles the central passage34with the ends of the wick32abutting 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 wick32extending into the toroidal cavity.

An air inhalation port38is provided at the back end of the atomizer/liquid reservoir portion16remote from the end cap12. The inhalation port38may be formed from the cylindrical hollow tube atomizer/liquid reservoir portion16or may be formed in an end cap.

In use, a user sucks on the e-cigarette10. This causes air to be drawn into the e-cigarette10via one or more air inlets, such as air inlets20, and to be drawn through the central passage34towards the air inhalation port38. The change in air pressure which arises is detected by the airflow sensor26, which generates an electrical signal that is passed to the control electronics24. In response to the signal, the control electronics24activate the heating coil30, which causes liquid present in the wick32to be vaporized creating an aerosol (which may comprise gaseous and liquid components) within the central passage34. As the user continues to suck on the e-cigarette10, this aerosol is drawn through the central passage34and inhaled by the user. At the same time, the control electronics24also activate the LED18causing the LED18to light up, which is visible via the translucent end cap12. Activation of the LED may mimic the appearance of a glowing ember at the end of a conventional cigarette. As liquid present in the wick32is converted into an aerosol, more liquid is drawn into the wick32from the liquid reservoir36by capillary action and thus is available to be converted into an aerosol through subsequent activation of the heating coil30.

Some e-cigarette are intended to be disposable and the electric power in the battery22is intended to be sufficient to vaporize the liquid contained within the liquid reservoir36, after which the e-cigarette10is thrown away. In other embodiments, the battery22is rechargeable and the liquid reservoir36is refillable. In the cases where the liquid reservoir36is a toroidal cavity, this may be achieved by refilling the liquid reservoir36via a refill port (not shown inFIG. 1). In other embodiments, the atomizer/liquid reservoir portion16of the e-cigarette10is detachable from the power supply portion14and a new atomizer/liquid reservoir portion16can be fitted with a new liquid reservoir36thereby replenishing the supply of liquid. In some cases, replacing the liquid reservoir36may involve replacement of the heating coil30and the wick32along with the replacement of the liquid reservoir36. A replaceable unit comprising the atomizer28and the liquid reservoir36may be referred to as a cartomizer.

The new liquid reservoir may be in the form of a cartridge (not shown inFIG. 1) 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 port38.

Of course, in addition to the above description of the structure and function of a typical e-cigarette10, variations also exist. For example, the LED18may be omitted. The airflow sensor26may be placed, for example, adjacent to the end cap12rather than in the middle of the e-cigarette. The airflow sensor26may 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 airflow 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. 2Ais a partial exploded assembly view of an eCig power supply portion212(also referred to as a power supply portion), consistent with various aspects of the present disclosure. The power supply portion212houses a number of electrical components that facilitate the re-charging and re-use of the power supply portion212with disposable and refillable atomizer/liquid reservoir portions (14as shown inFIG. 1), which are also referred to as atomizer/liquid reservoir portions. A battery218is electrically coupled to controller circuitry222on a printed circuit board. An airflow sensor224for determining one or more characteristics of a user's draw from the eCig is also located on the printed circuit board, and communicatively coupled to the controller circuitry222. In various embodiments consistent with the present disclosure, the airflow sensor224may be a mass airflow sensor, a pressure sensor, a velocity sensor, a heater coil temperature sensor, or any other sensor that may capture relevant draw characteristics (either directly or through indirect correlations). In the present embodiment, the airflow sensor224is a mass airflow sensor that determines the flow of air across the airflow sensor224. The measured flow of air is then drawn through the atomizer/liquid reservoir portion, where heater coils atomize eCig juice into the air, and into a user's mouth. Accordingly, by measuring the mass flow rate of air through the power supply portion212, the controller circuitry222may adjust a heating profile of a heating coil in a atomizer/liquid reservoir portion (e.g., power, length of time, etc.), as well as provide a variable indication of the strength of the draw—by way of LEDs220A-E, which may be independently addressed by the controller circuitry or powered at varying intensities to indicate characteristics indicative of the eCig's functionality. For example, varying the illumination intensity based on the sensed mass airflow. In further embodiments, the LEDs may also indicate other functional aspects of the eCig, such as remaining battery life, charging, sleep mode, among others.

In various embodiments of the present disclosure, electrical pins extending from the printed circuit board may be electrically coupled to a atomizer/liquid reservoir portion, and thereby allow for both energy transfer and data communication between the power supply portion212and the atomizer/liquid reservoir portion (not shown). In various other embodiments, pins may extend from a surface of the printed circuit board to an exterior of the power supply portion to facilitate charging and data communication with external circuitry.

To provide user indications of status, power remaining, use, error messages, among other relevant information, a flexible printed circuit board221is communicatively coupled to controller circuitry222via wire leads242A-B. The flexible circuit board221may include one or more light sources. In the present embodiment, the flexible circuit board221includes LEDs220A-E. When assembled into the rest of the power supply portion212, the LEDs220A-Eboth illuminate a circumferential portion of light guide216, and a tip diffuser246that illuminates a distal end of the light guide216. The tip diffuser246and the light guide216together facilitate even illumination of the distal end of the power supply portion212in response to the activation of the LEDs220A-E.

As shown inFIG. 2A, once electrically coupled to one another (e.g., by solder), battery218, flexible printed circuit board221, and a printed circuit board containing controller circuitry222and airflow sensor224are encased by upper sub-assembly housing240and lower sub-assembly housing241. In one embodiment, the upper sub-assembly housing240and the lower sub-assembly housing241can create a flow channel. The flow channel created by the upper sub-assembly housing240and the lower sub-assembly housing241can direct airflow over the airflow sensor. The sub-assembly housing portions positively locate the various components with the sub-assembly. In many embodiments, the sub-assembly housing portions utilize locating pins and integral locking features to maintain the sub-assembly after assembly.

Once assembly is complete on the sub-assembly, the sub-assembly may be slid into tube245from one end, and tip diffuser246and circumferential light guide216may be inserted from the opposite end of the tube to complete assembly of power supply portion212. By way of the distal tip of the circumferential light guide216and etch pattern248in tube245, LEDs220A-Emay illuminate evenly around a distal circumferential portion of the tube245, and a distal tip of the power supply portion212.

In various embodiments of the present disclosure, one or more keying features may be present on an exterior surface of upper and/or lower sub-assembly housing portions240and241. When the sub-assembly is inserted into tube245, mating keying features along an inner surface of the tube245rotationally align the tube and the sub-assembly along a longitudinal axis and prevent the sub-assembly from spinning therein.

The use of a sub-assembly during manufacturing helps minimize assembly complexity, as well as reduce overall assembly time. Moreover, the sub-assembly helps to mitigate scrap as the sub-assembly allows for rapid re-work of a power supply portion212, such as when electronic circuitry within the power supply portion fails in testing. Moreover, the sub-assembly helps to mitigate common failure modes of eCigs during its useful life by reducing shock and vibration related damage to the sub-components. Specifically, by positively locating controller circuitry222and flexible circuit board221within the upper and lower sub-assembly housing portions240and241, wire leads242A-Band bonding pads electrically coupling the circuitry are less likely to experience failure modes. For example, stress fractures at a solder joint on a bonding pad.

In various embodiments of the present disclosure, pattern248on tube245may include various different patterns, shapes, images and/or logos. In the present embodiment, the pattern248is a plurality of triangles positioned in proximity to one another. The pattern248may be laser etched onto a painted surface of the tube245, silk screened, drilled or otherwise cut into an outer surface of the tube245, and/or the tube itself can be translucent or semi-translucent and the pattern may be disposed on an outer surface350of circumferential light guide316. The pattern248on an outer surface of tube245allows controller circuitry222to provide visual indications of the eCigs functionality via light being emitted from LEDs220A-Ethrough circumferential light guide216. The eCig may provide a plurality of visual indications by varying the brightness (e.g., LED duty cycle), color (e.g., output frequency and/or multi-diode LEDs), location, on/off time, patterning, among other visually distinguishable characteristics.

FIG. 2Bis a partial exploded assembly view of an eCig power supply portion sub-assembly213, consistent with various aspects of the present disclosure. As shown inFIG. 2B, flex circuit221and battery218are electrically coupled to controller circuitry222via wire leads which are soldered on to the controller circuitry. Contacts225A-C(also referred to as electrical pins) are also electrically coupled to the controller circuitry222and extend toward apertures within the upper sub-assembly housing240. The contacts225A-Cfacilitate electrical communication between the controller circuitry222and an external circuit, as well as charging the battery218.

When assembled, flex circuit221extends over and around battery218. The battery being circumferentially enclosed by upper and lower sub-assembly housing portions240and241. Controller circuitry222is sandwiched between spacer229and MAF gasket228; the spacer and MAF gasket contacting respective surfaces of upper and lower sub-assembly housing portions240and241and thereby positively locate the controller circuitry within the sub-assembly. The spacer229includes an inner aperture that functions as a light guide to deliver light from an LED on the controller circuitry222through an aperture within the lower sub-assembly housing241. The MAF gasket228facilitates an airflow passage between the controller circuitry222and the upper sub-assembly housing240. The MAF gasket228both forms a seal between the controller circuitry222and the upper sub-assembly housing to direct the airflow past the airflow sensor224(as shown inFIG. 2A), as well as to maintain a desired cross-sectional area of the airflow passage in the vicinity of a mass airflow sensor.

Female connector port258mates to a male connector port on a atomizer/liquid reservoir portion of the eCig, and provides a flow of air via a fluid outlet, and power and data communication signals via a plurality of electrical contacts that are communicatively coupled to corresponding electrical contacts on the male connector port (when the male and female connector ports are mated to one another). In various embodiments of the present disclosure, the male and female connector ports are hemicylindrical in shape. As used herein, “hemicylindrical” describes parts having the shape of a half a cylinder, as well as parts that include a larger or smaller portion of a cylinder when cut by a plane that is parallel to the longitudinal axis (or lengthwise) of the cylinder. An airflow gasket227is inserted into the female connector port258and facilitates a fluid seal with the mating male connector port. In one particular embodiment, airflow sensor224is a mass airflow sensor that measures a flow of air through the eCig, the airflow gasket227prevents additional air from entering the airflow into the atomizer/liquid reservoir portion (or the escape of air from the airflow) after the mass airflow sensor has measured the airflow.

Once the sub-assembly213has been assembled and inserted into an outer tube245, a locking pin226is inserted through corresponding apertures in the outer tube and the upper sub-assembly housing240to axially and rotationally couple the sub-assembly213within the power supply portion212.

FIG. 3shows an example of the microcontroller320constructed according to an aspect of the disclosure. The microcontroller320comprises a microcomputer326, a memory324and an interface328. The microcontroller320can include a driver322that drives an atomizer (not shown). The driver322can include, e.g., a pulse-width modulator (PWM) or signal generator. The microcomputer320is configured to execute a computer program, which can be stored externally or in the memory324, to control operations of the eCig, including activation (and deactivation) of the heating element. The memory324includes a computer-readable medium that can store one or more segments or sections of computer code to carry out the processes described in the instant disclosure. Alternatively (or additionally) code segments or code sections may be provide on an external computer-readable medium (not shown) that may be accessed through the interface328.

It is noted that the microcontroller320may include an application specific integrated circuit (IC), or the like, in lieu of the microcomputer326, driver322, memory322, and/or interface328.

The microcontroller may be configured to log medium flow data, including mass flow, volume flow, velocity data, time data, date data, flow duration data, and the like, that are associated with the medium flow. The medium may comprise an aerosol, a gas (e.g., air), a liquid, or the like. The microcontroller may be configured not only to turn ON/OFF a heater based on such data, but to also adjust control parameters such as heater PWM or amount of liquid solution dispensed onto a heating surface. This control may be done proportionally to the flow data or according to an algorithm where flow data is a parameter. In addition, the microcontroller may use flow data to determine flow direction and restrict or limit false activation of the heater in case the user accidentally blows into the eCig.

FIG. 4shows an example of a flow sensor330that is constructed according to an aspect of the disclosure. The flow sensor330comprises a substrate331and a thermopile (e.g., two or more thermocouples), including an upstream thermopile (or thermocouple)332and a downstream thermopile (or thermocouple)333. The substrate331may include a thermal isolation base. The flow sensor130may comprise a heater element334. The flow sensor330may comprise a reference element335. The heater element334may include a heater resistor. The reference element335may include a reference resistor.

As seen inFIG. 4, the thermopiles332,333may be symmetrically positioned upstream and downstream from the heater element334. The heater element334heats up the hot junctions of the thermopiles332,333. In response, each of the thermopiles332,333generates an output voltage that is proportional to the temperature gradient between its hot and cold junctions (the “Seebeck” effect). The hot junctions of the thermopiles332,333and the heater element334may reside on the thermal isolation base. Mass airflow sensor signal conditioning may be composed of various forms of filters or gain amplifiers. Filters may be used to eliminate noise before or after signal amplification, thereby reducing sensitivity to unwanted environmental noises or pressure changes. Filtering can be accomplished using low pass, high pass, band pass, or a combination thereof. Signal gain amplification may be accomplished by employing electronic amplification on the upstream or downstream thermopile signals, or a combination thereof. Amplification of upstream or downstream thermopile signals may use a single state or multiple cascaded stages for each signal, or combination of these signals to form a sum or difference. The amplifier circuit may include means to introducing a signal offset. The amplifier may include transistors, operational amplifiers, or other integrated circuits.

FIGS. 5A and 5Billustrate an example of a single amplifier with a filter364and a difference amplifier and filters for upstream and downstream, with offset380. As shown in the single amplifier with a filter364inFIG. 5A, the airflow signal360passes through a filter361and a gain amplifier362before a signal output363is transmitted. The difference amplifier and filters for upstream and downstream, with offset380shown inFIG. 5Bcomprises an upstream airflow signal370and a downstream airflow signal371. The upstream airflow signal370passes through a first filter372and the downstream airflow signal passes through a second filter373. The outputs of the first and second filters371,372then enter a difference amplifier374. A signal is then output from the difference amplifier374and enters a gain amplifier375along with an offset375. The gain amplifier376then outputs a signal output377.

FIG. 6illustrates an electrical diagram of an embodiment of the disclosure comprising a first thermopile452and a second thermopile453. The eCig depicted inFIG. 6comprises a microcontroller440, a mass airflow sensor450, an amplifier449, and a heater456. The mass airflow sensor450comprises a mass airflow heater451, a first thermopile452, and a second thermopile453. The electrical diagram further illustrates the direction of airflow454over the mass airflow heater451and the first and second thermopiles452,453. The microcontroller440can comprise a data acquisition circuit441, and an analog-to-digital converter442. The data acquisition circuit441can log and transmit data such as temperature of the heater456, the number of times the heater256has been activated in a certain time, the length of time the heater456had been activated, and other information. A more detailed description of data acquisition and transmission can be found in commonly assigned U.S. Provisional Application No. 61/907,239 filed 21 Nov. 2013, the entire disclosure of which is hereby incorporated by reference as though fully set forth herein. The analog-to-digital converter442can output information about the eCig to the microcontroller440, the data acquisition circuit441, and other devices and sensors that may be present on the microcontroller440or otherwise connected to the eCig.

FIG. 7illustrates an electrical diagram of another embodiment of the disclosure comprising one thermopile552. The eCig depicted inFIG. 7comprises a microcontroller540, a mass airflow sensor550, an amplifier549, and a heater556. The mass airflow sensor550comprises a mass airflow heater551and a thermopile552. The electrical diagram further illustrates the direction of airflow over the heater554and the thermopile552. The microcontroller540can comprise a data acquisition circuit541, and an analog-to-digital converter542. The data acquisition circuit541can log and transmit data such as temperature of the heater556, the number of times the heater556has been activated in a certain time, the length of time the heater556had been activated, and other information. The analog-to-digital converter542can output information about the eCig to the microcontroller540, the data acquisition circuit541, and other devices and sensors that may be present on the microcontroller540or otherwise connected to the eCig. In one embodiment, the eCig can also comprise feedback and gain resistors557,558. More information regarding the airflow sensor can be found in PCT Publication no. WO 2014/205263, filed 19 Jun. 2014, which is incorporated by reference herein as though set forth in its entirety.

FIGS. 8A and 8Bshow an example of a flow channel according to the principles of the disclosure. As seen inFIGS. 8A and 8B, the flow channel can be shaped in the vicinity of the sensor so as to direct a majority of flow over the sensing surface, thus increasing the sensitivity of the system.FIG. 8Adepicts a top down view of one embodiment of a flow channel601.FIG. 8Bdepicts an end view of the flow channel601shown inFIG. 8A. The flow channel601comprises a first side wall603, a second side wall605, a top wall623, a bottom wall625, an incoming airflow opening611, an incoming airflow pathway607, a sensor assembly615, an outgoing airflow pathway609, and an outgoing airflow opening613. The first side wall603, the second side wall605, the top wall623, and the bottom wall625define the incoming airflow opening611, the incoming airflow pathway607, the outgoing airflow pathway609, and the outgoing airflow opening613. The incoming airflow opening611can allow air to enter the flow channel601. The incoming airflow pathway607can extend along a longitudinal axis of the flow channel601. The incoming airflow pathway607can extend a distance along the longitudinal axis and comprise enough volume so that any air entering the flow channel601through the incoming airflow opening611creates a laminar flow before passing over the sensor assembly615. In one embodiment, to achieve a laminar flow over the sensor assembly, the incoming airflow pathway can comprise a longitudinal length of 1.5-2 mm. In other embodiments, the longitudinal length of the incoming airflow pathway can be adjusted in response to different dimensions and volumes of the flow channel. The sensitivity of the sensor assembly615can be increased by decreasing the volume of the flow channel601. However, by decreasing the volume of the flow channel601adraw resistance for a user is increased. As the volume of the flow channel601increases the signal quality decreases, but the draw resistance is decreased. After the air has passed over the sensor assembly615, the airflow can be turbulent as it passes through the rest of the system. The sensor assembly615can comprise a sensor617. The sensor617can detect an airflow over the sensor assembly615and can further detect a mass of airflow over the sensor assembly615and passing through the flow channel601. The airflow can move over the sensor along the airflow path619In one embodiment, the sensor can comprise a mass airflow sensor. In another embodiment, the sensor can comprise a capacitive sensor. After passing over the sensor assembly615, an airflow through the flow channel601can enter the outgoing airflow pathway609and exit the flow channel601through the outgoing airflow opening613. After leaving the flow channel601, the airflow can enter an external airflow pathway621. In one embodiment, the external airflow pathway621can be sealed such that any air entering the flow channel601and passing over the sensor assembly615can be routed through the flow channel601and the external airflow pathway621to an atomizer (not shown).

In other embodiments, a diverter can be present after the airflow has passed over the sensor assembly such that a portion of the air passes over the atomizer and a portion of the air diverts around the atomizer. In these embodiments, the electronic smoking device is configured to, at least in part, pass the airflow over the atomizer. In one embodiment, the portion of air that passes over the atomizer can be 50% or greater of the air that passes over the sensor assembly. In another embodiment, the portion of air that passes over the atomizer can be 50% or less of the air that passes over the sensor assembly. By diverting a portion of the airflow that passes over the sensor assembly, the amount of air that passes over the atomizer can be controlled and the amount of aerosol or vapor created by the atomizer can be regulated. In yet other embodiments, an additional air inlet can be added downstream of the sensor assembly, such that additional air can be added to the airflow that has passed over the sensor assembly. In one embodiment, adding an additional air inlet downstream of the sensor assembly can decrease the sensitivity of the sensor signal, but can further dilute the vapor stream. In yet other embodiments, additional components can be added to divert or add airflow to the airflow stream after it has passed the sensor assembly. The additional components can be used to divert the airflow stream away from the atomizer, add additional air to the airflow stream, or impart additional airflow after the airflow stream has passed the atomizer. In yet other embodiments, the airflow passing over the sensor assembly can comprise a first portion of the airflow passing through a downstream portion of the electronic smoking device. A second portion of the airflow passing through an upstream portion of the electronic smoking device can be diverted around the sensor assembly. In one embodiment, the second portion of the airflow can join with the first portion of the airflow after the first portion of the airflow has passed over the sensor assembly. In one embodiment, the atomizer can comprise a heater. In other embodiments, the atomizer can comprise a mechanical or thermal atomizer as would be known to one in the art. In one embodiment, the flow channel can be defined by the foam and plastic portions of the battery housing as illustrated inFIGS. 2A and 2B. In one embodiment, the foam portion of the flow channel can comprise a minimum compression ratio of 30%. When foam is used within the flow channel, the foam can be compressed enough to keep the flow channel sealed, but not compressed to an extent that the foam intrudes into the channel. In one embodiment, the foam can comprise a micro closed-seal foam.

FIG. 9illustrates a side view of one embodiment of a sensor assembly651. The sensor assembly651can comprise a support structure653, a sensor655, a first layer659, and a second layer661. The support structure653can comprise a PCB or other component that can be electrically coupled to the sensor655. The sensor655can detect an airflow over the sensor assembly651and can further detect a mass of airflow over the sensor assembly651. In one embodiment, the sensor can comprise a mass airflow sensor. In another embodiment, the sensor can comprise a capacitive sensor. The first layer659and the second layer661can be used to create an upper surface663that extends along an incoming portion665of the sensor assembly651. The upper surface663can comprise a height above the support structure653similar to the height the sensor655extends above the support structure653. The upper surface663created by the first layer659and the second layer661can be used to minimize turbulence created by an airflow passing through an airflow pathway667and over the sensor assembly651. The first layer659can comprise any one of a number of substances that can be used during a PCB manufacturing process. In one embodiment, the first layer659can comprise copper. In other embodiments, the first layer659can comprise solder mask, silkscreen, or any other material that can be deposited on a PCB or other support structure. The second layer661can comprise any one of a number of substances that can be used during a PCB manufacturing process. In one embodiment, the second layer661can comprise solder mask. In other embodiments, the second layer661can comprise copper, silkscreen, or any other material that can be deposited on a PCB or other support structure. In one embodiment, a silkscreen layer can be further deposited on top of the second layer661. These materials can be used during the manufacturing of the sensor assembly651. Using materials already present during the manufacture of a PCB component, additional manufacturing costs can be limited. In one embodiment, the sensor can be formed and then a backgrinding process can be used to remove portions of the sensor that are not integral to the sensor. By backgrinding the sensor, the height of the sensor can be decreased, requiring less additional material to be placed on the support structure. In one embodiment, after undergoing the backgrinding process the sensor can comprise a height of 0.1 mm. In another embodiment, after undergoing the backgrinding process the sensor can comprise a height of 0.2 mm.

FIG. 10depicts a schematic view of another embodiment of a sensor assembly701. The sensor assembly701can comprise a support structure703, a sensor705a first structure component707, and a second structure component709. The sensor705can be coupled to the support structure703. In one embodiment, the sensor705can be electrically coupled to the support structure703. The first structure component707and the second structure component709can be coupled to the support structure703. The first structure component707and the second structure component709can assist in securing the sensor705to the support structure703. In another embodiment, the first structure component707and the second structure component709can each comprise an upper surface adjacent to an upper surface of the sensor705. The first support structure707and the second support structure709can be used to assist in directing an airflow over the sensor705and to minimize air currents that could be disruptive or otherwise unwanted when air is passed over the sensor705.

FIG. 11Aillustrates another embodiment of a sensor assembly751. The sensor assembly751can comprise a support structure753, a sensor base portion757, a sensor top portion755, and a sensor transition region759. The support structure753can comprise a depression sized and configured to house the sensor base portion757. When the sensor base portion757is placed within the depression of the support structure753, the sensor top portion755can be above an upper portion of the support structure. The sensor transition region759can be lined up with an upper surface of the support structure753. By securing the sensor base portion757within a depression of the support structure753, the sensor top portion755can minimize any effects of the sensor top portion755on airflow flowing past the sensor assembly751. As stated above, in other embodiments, additional material can be placed on the support structure to further minimize any effects, turbulence or otherwise, possibly caused on an airflow passing over the sensor assembly751.

FIG. 11Billustrates the sensor ofFIG. 11A. The sensor comprises the sensor base portion757, the sensor top portion755, and the sensor transition region759. As described above, the sensor base portion757can be placed within a depression in a support structure. In other embodiments, the sensor base portion757can be coupled to a top surface of a support structure. The sensor top portion755can comprise the portion of the sensor that is needed to interact with an airflow passing over the sensor to measure an airflow rate. In one embodiment, the sensor transition region759can be denoted as separating the portion of the sensor that needs to be exposed to a passing airflow (the sensor top portion755) and the portion of the sensor that does not need to be exposed to a passing airflow (the sensor bottom portion757).

FIG. 12Adepicts a schematic view of one embodiment of a flow channel801. The flow channel801can comprise an upper housing803, a support structure805, a support depression807, a sensor809, and an airflow pathway811. The upper housing803, the support structure805, and the sensor809can define the airflow pathway811. Air entering the flow channel801can pass over the sensor809in the airflow direction813. The support depression807can be sized and configured to house a lower portion of the sensor809. When the lower portion of the sensor809is placed within the support depression807, an upper portion of the sensor809can be above an upper surface of the support structure805. By securing the sensor809within the support depression807, the sensor809can minimize any effects on airflow flowing past the sensor809. As stated above, in other embodiments, additional material can be placed on the support structure to further minimize any effects, turbulence or otherwise, possibly caused on an airflow passing over the sensor809. The upper housing can comprise a variety of materials. In one embodiment, the upper housing can comprise plastic. In another embodiment, the upper housing can comprise tape placed over the flow channel. In yet other embodiments, the upper housing can comprise any other material that can withstand deformation from air flowing through the airflow pathway.

FIG. 12Bdepicts a schematic view of another embodiment of a flow channel831. The flow channel831can comprise an upper housing833, a support structure835, a sensor837, a first structure component841, a second structure component839, and an airflow pathway843. The upper housing833, the support structure835, the first structure component841, the second structure component839, and the sensor837can define the airflow pathway843. Air entering the flow channel831can pass over the sensor837in the airflow direction845. The sensor837can be coupled to the support structure835. In one embodiment, the sensor837can be electrically coupled to the support structure835. The first structure component841and the second structure component839can be coupled to the support structure835. The first structure component841and the second structure component839can assist in securing the sensor837to the support structure835. In another embodiment, the first structure component841and the second structure component839can each comprise an upper surface adjacent to an upper surface of the sensor837. The first support structure841and the second support structure839can be used to assist in directing an airflow over the sensor837and to minimize air currents that could be disruptive or otherwise unwanted when air is passed over the sensor837. The upper housing can comprise a variety of materials. In one embodiment, the upper housing can comprise plastic. In another embodiment, the upper housing can comprise tape placed over the flow channel. In yet other embodiments, the upper housing can comprise any other material that can withstand deformation from air flowing through the airflow pathway.

FIG. 12Cdepicts a schematic view of another embodiment of a flow channel861. The flow channel861can comprise an upper housing863, a first side support structure865, a second side support structure879, a sensor support structure867, a sensor869, an airflow pathway871, an airflow sensor entrance875, and an airflow sensor exit877. The upper housing863, the first side support structure865, the second side support structure879, the sensor support structure867, and the sensor869can define the airflow pathway871. The first side support structure865and the sensor support structure867can define an airflow sensor entrance875. The sensor support structure867and the second side support structure879can define an airflow sensor exit877. Air entering the flow channel861can enter through the airflow sensor entrance875, can pass over the sensor869, and can exit through the airflow sensor exit877in the airflow direction873. As described above, the sensor869can be placed within a depression in the sensor support structure867. The upper housing can comprise a variety of materials. In one embodiment, the upper housing can comprise plastic. In another embodiment, the upper housing can comprise tape placed over the flow channel. In yet other embodiments, the upper housing can comprise any other material that can withstand deformation from air flowing through the airflow pathway.

FIG. 13depicts a graph illustrating one embodiment of the power delivered for a given flow rate901. The depicted graph illustrates a response curve903showing a logarithmic graph with a power level for a sensed airflow rate. As seen in the illustrated embodiment, a first position905on the graph comprises a power level of 4 W that can be output to an atomizer at a first flow rate. A second position907on the graph comprises a power level of 10 W that can be output to an atomizer at a second flow rate. The response curve comprises a logarithmic curve where the power output is exponential in response to the flow rate. An exponential increase in power output can be used as an atomizer may not be properly heated with an increasing rate of airflow using a linear response. In other embodiments, the power output can be increased in an exponential fashion in response to an increased airflow so that the atomizer can deliver a larger amount of aerosol in response to a larger or faster rate of airflow over the sensor and through the system as a whole. The larger amount of aerosol produced by the atomizer can attempt to mimic the increased amount of smoke that can be produced by a user who takes a deeper or longer drag on a traditional cigarette. In another embodiment, where an increase in aerosol is not desired, the power output can comprise a linear increase as airflow is increased.

FIG. 14depicts a graph illustrating several embodiments of response to flow rate921. The response illustrated inFIG. 14is the response from the airflow sensor for a given flow rate. The graph illustrates a first response curve923, a second response curve925, and a third response curve927. Each of the first response curve923, the second response curve925, and the third response curve927illustrate a response from different individual airflow sensors. The second response curve925further depicts a plurality of response points929. The plurality of response points can each individually comprise a known response for a given flow rate. In another embodiment, only a portion of the plurality of response points929can be determined during testing and other of the plurality of response points929can be determined by calculating a curve to fit the determined response points. As shown inFIG. 14, a first response flow rate931can comprise a 5 ml/s flow rate and a second response flow rate935can comprise a 40 ml/s flow rate.

FIG. 15depicts a graph illustrating one embodiment of a flow v time output941. The flow v time output941comprises a user puff943. The user puff943comprises a varying flow rate over time. As shown in the depicted user puff943, initially the flow rate is negligible. At a later time, a user initiates the puff, and the flow rate increases until it reaches a maximum flow rate. The flow rate then slowly lowers over the course of time, until dropping back to the initial negligible flow rate.

FIG. 16depicts a graph illustrating several embodiments of response to flow rate961. As seen inFIG. 14, the response illustrated is the response from the airflow sensor for a given flow rate. The graph illustrates a first response curve963, a second response curve965, a third response curve967, and a fourth response curve969. Each of the first response curve963, the second response curve965, the third response curve967, and the fourth response curve969illustrate a response from different individual airflow sensors. As seen in the illustrated embodiments, all of the sensors have different curves and different baseline conditions. The signals from each sensor can then be driven higher or lower to bring each sensor to a common baseline signal. Even after a common baseline signal has been assigned, each sensor still displays a different curve. The curve for each sensor can be calculated by determining the response signal for a subset of airflow rates. In one embodiment, three response signals can be determined to calculate the response curve. In the illustrated embodiment, the response signals can be determined at a first response location971, a second response location973, and a third response location975. In one embodiment the three response signals can be recorded at 15 ml/s, 25 ml/s, and 40 ml/s. The response signal received at each of the three flow rates can be used to calibrate the response curve. Each of the sensors comprises a response curve that is logarithmic or exponential. The response curve can be used to generate a table of points979that can be looked up by the system. The number of points within the look up table can vary. In one embodiment, the look up table can comprise 32 values. Other embodiments can have fewer or more points within the look up table. In another embodiment, an equation can be used to determine a flow rate for a specific signal. In another embodiment, the look up table can be limited in maximum range to what can be performed by a user using the device. In one embodiment, that upper range can comprise 40 ml/s to 50 ml/s. Further, the lowest airflow than an average user will be able to sustain for a light puff is about 15 ml/s. As a result, the normal range that can be used within the lookup table is 15 ml/s to 40 ml/s. In another embodiment, the normal range that can be used within the lookup table is 15 ml/s to 50 ml/s. In yet another embodiment, the normal range that can be used is 5 ml/s to 50 ml/s. In yet other embodiments, other ranges can be used. In one embodiment, the responsiveness can be scaled in terms of power output within that range. In another embodiment, an airflow rate above 35 ml/s will not increase a power output to the atomizer. In yet another embodiment, an airflow rate below 15 ml/s will not decrease the power output to the atomizer. Further, in one embodiment, the values included in the look up table are not evenly spread out. In this embodiment, the values above 35 ml/s can be further apart than those below 35 ml/s. In another embodiment, a threshold airflow rate of 5 ml/s can be used to start a puff event. While 5 ml/s airflow rate can be used to start a puff event, the coil does not energize until an airflow rate of 10 ml/s occurs. In one embodiment, the baseline value ceases updating after the puff event starts at 5 ml/s. Further, in another embodiment, the atomizer starts energizing at 10 ml/s, and then once the airflow rate decreases below 10 ml/s, the atomizer stops energizing. Further, the puff event stops after the airflow rate drops below 5 ml/s. Further, in other embodiments, the energization and puff event values can comprise different amounts than those listed herein.

FIG. 17illustrates a flow-chart of the process by which the microcontroller or other component can interpret signals from the mass airflow sensor or other device. In step1000a microcontroller can monitor a sensor signal sent from the mass airflow sensor. When the microcontroller monitors a change in the sensor signal that is being monitored in step1000, the microcontroller can determine if the change in the sensor signal is below a programmed threshold1001. If the change in the sensor signal over a length of time is below the programmed threshold the microcontroller or other component can alter a reference signal and a relation signal to a predetermined baseline1002. In one embodiment the reference signal can be set to a baseline reading of 2.0 volts. The microcontroller than continues to monitor the mass airflow sensor for a change in the sensor signal1000. If the change in the sensor signal over time is above a programmed threshold1001, then the microcontroller or other component reads the difference between the reference signal and the relation signal1003. In step1004, the microcontroller or other component can operate a device, sensor, or other component according to the difference between the reference signal and the relation signal. The process then goes back to step1000and the microcontroller or other component continues to monitor the mass airflow sensor for a change in the sensor signal over time.

The sensor can drift as the temperature of the sensor increases. The drift can comprise about 0.1% per degree Celsius. While the drift can appear minimal, at higher end flow rates, because of the low overall signal, the small difference can make a big difference in the sensed airflow rate. To account for the temperature drift error two approaches can be used. The first approach is to add a thermistor to the sensor. This thermistor can be powered through the offset and the resistance of the thermistor can vary with temperature. The resistance can be sampled and the temperature of the sensor can be determined. The second approach can use the sensor itself and look at the value output by the sensor when a puff event starts and use this signal as a baseline. A baseline of when a puff event is not occurring and a signal output by the sensor when a puff event occurs. The baseline signal when a puff event is not occurring will tend to shift slightly. This shift can be correlated to temperature. In one embodiment, a look up table can be used to determine a temperature shift. In another embodiment, an algorithm can be used to determine a temperature shift. The temperature shift described herein can be used for any airflow sensor, including mass airflow sensors, capacitive sensors, or others as would be known to one of ordinary skill in the art.

Various embodiments of the present disclosure are directed to an electronic smoking device. The electronic smoking device can comprise a flow channel and an atomizer. The flow channel can comprise an incoming airflow opening, an incoming airflow pathway, a sensor assembly, and an outgoing airflow opening. The atomizer can be fluidly coupled to the flow channel. The flow channel can be configured to direct an airflow from the incoming airflow opening, through the incoming airflow pathway, over the sensor assembly, and through the outgoing airflow opening. The electronic smoking device can further be configured to pass the airflow, at least in part, over the atomizer. In a more specific embodiment, the electronic smoking device can further comprise an outgoing airflow pathway between the sensor assembly and the outgoing airflow opening. In a more specific embodiment, the electronic smoking device can further comprise an external airflow pathway coupled to the flow channel, wherein the external airflow pathway is configured to direct air from the outgoing airflow opening to the atomizer.

In a more specific embodiment, the flow channel further comprises a first side wall, a second side wall, a bottom wall, and a top wall, and wherein the first side wall, the second side wall, the bottom wall, and the top wall define the incoming airflow opening. In a more specific embodiment, the flow channel is sized and configured to create a laminar flow of air in the incoming airflow pathway before the airflow reaches the sensor assembly. In some embodiments, the sensor assembly comprises a support structure and a sensor, and wherein the sensor is coupled to the support structure. In other embodiments, the sensor assembly further comprises a first layer and a second layer coupled to the support structure. In yet other embodiments, the first layer and the second layer create an upper surface. In other embodiments, the upper surface comprises a height above the support structure similar to a height of the sensor. In yet other embodiments, the upper surface is configured to minimize turbulence of the airflow over the sensor. In some embodiments, the first layer comprises copper. In other embodiments, the second layer comprises solder mask. In yet other embodiments, the sensor assembly further comprises a silkscreen material deposited on top of the second layer.

In another embodiment, the support structure comprises a PCB. In yet another embodiment, the support structure comprises a support depression. In other embodiments, a lower portion of the sensor is sized and configured to fit within the support depression. In some embodiments, the sensor assembly further comprises a sensor, and wherein the sensor comprises a height of no more than 0.2 mm.

Other various embodiments consistent with the present disclosure are directed to an electronic smoking device. The electronic smoking device can comprise a flow channel. The flow channel can comprise an incoming airflow opening, an incoming airflow pathway, a sensor assembly, and an outgoing airflow opening. The flow channel can be configured to direct an airflow from the incoming airflow opening, through the incoming airflow pathway, over the sensor assembly, and through the outgoing airflow opening. In other various embodiments, the flow channel is sized and configured to create a laminar flow of air in the incoming airflow pathway before the airflow reaches the sensor assembly. In yet other embodiments, the sensor assembly comprises a support structure, a first layer, a second layer, and a sensor, and wherein the sensor, the first layer, and the second layer are coupled to the support structure.

The terms “including,” “comprising” and variations thereof, as used in this disclosure, mean “including, but not limited to,” unless expressly specified otherwise.

Although process steps, method steps, algorithms, or the like, may be described in a sequential order, such processes, methods and algorithms may be configured to work in alternate orders. In other words, any sequence or order of steps that may be described does not necessarily indicate a requirement that the steps be performed in that order. The steps of the processes, methods or algorithms described herein may be performed in any order practical. Further, some steps may be performed simultaneously.

Although several embodiments have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit of the present disclosure. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the present teachings. The foregoing description and following claims are intended to cover all such modifications and variations.

It will be appreciated that the terms “proximal” and “distal” may be used throughout the specification with reference to a clinician manipulating one end of an instrument used to treat a patient. The term “proximal” refers to the portion of the instrument closest to the clinician and the term “distal” refers to the portion located furthest from the clinician. It will be further appreciated that for conciseness and clarity, spatial terms such as “vertical,” “horizontal,” “up,” and “down” may be used herein with respect to the illustrated embodiments. However, surgical instruments may be used in many orientations and positions, and these terms are not intended to be limiting and absolute.

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