Abstract:
An electronic cigarette includes a cartridge ( 12 ) and an atomizing assembly ( 13 ); the atomizing assembly ( 13 ) is fixed in the cartridge ( 12 ); the atomizing assembly ( 13 ) comprises a reservoir ( 105 ), a liquid guiding medium ( 106 ) and a heating element ( 107 ); the reservoir ( 105 ) has a liquid storage cavity ( 108 ) storing tobacco liquid and a liquid outlet ( 109 ); the liquid outlet ( 109 ) communicates with the liquid storage cavity ( 108 ); the liquid guide medium ( 106 ) is porous liquid guiding material, and is connected to the liquid outlet ( 109 ); the heating element ( 107 ) is fixed in the cartridge ( 12 ), and a gap exists between the heating element ( 107 ) and the liquid guide medium ( 106 ); the liquid guide medium ( 106 ) guides the tobacco liquid out of the reservoir ( 105 ) via the liquid outlet ( 109 ) and stores the tobacco liquid; the gap exists between the heating element ( 107 ) and the liquid guide medium ( 106 ) so that the heating element ( 107 ) heats the liquid guide medium ( 106 ) without directly contacting the liquid guide medium ( 106 ), thus preventing the heating element ( 107 ) from polluting the atomized tobacco liquid, and being helpful to the health of a user.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure relates to a field of electronic atomizers, and more particularly relates to an electronic cigarette. 
       BACKGROUND OF THE INVENTION 
       [0002]    Electronic cigarette is also known as a virtual cigarette or an electronic atomizer. As a replacement for cigarettes, the electronic cigarette is usually used for smoking cessation. The appearance and taste of the electronic cigarette are similar to that of the conventional cigarette, while it does not contain tar, suspended particles and other harmful ingredients in the conventional cigarette. 
         [0003]    The electronic cigarette is mainly composed of an atomizer and a battery assembly. As a core device of the electronic cigarette to generate atomizing gas, the quality and taste of the smoke are dependent on the atomization effect of the atomizer. A conventional heating element of the atomizer is a spiral heating wire wrapped around a positioning shaft. When the heating wire is powered by the battery assembly, the liquid stored in the storage medium will be absorbed by the positioning shaft, and it is then atomized by the heat of the heating wire. However, the heating wire is normally a resistance wire, such as a nickel-chromium alloy resistance wire. When this type of resistance wire is in direct contact with the liquid, a small amount of metal elements (such as: chromium) or other trace elements (such as phosphorus, carbon, sulfur, etc.) will be generated during the atomizing process, such that the user may inhale cadmium, sulfur and other harmful substances during use, which is harmful to the health of the user. 
       SUMMARY OF THE INVENTION 
       [0004]    Accordingly, it is necessary to provide an electronic cigarette which is conducive to the health of users. 
         [0005]    An electronic cigarette includes: a cartridge; and an atomizing assembly fixed in the cartridge, the atomizing assembly including: a reservoir, the reservoir having a liquid storage chamber for storing liquid and a liquid outlet in fluid communication with the liquid storage chamber; a liquid guiding medium made of porous liquid guiding material and connected to the liquid outlet; and a heating element fixed in the cartridge, wherein the heating element and the liquid guiding medium form a gap therebetween. 
         [0006]    In one embodiment, the liquid reservoir has a tubular shape and defines an airflow channel, the liquid reservoir comprises opposed first and second ends, the liquid outlet is defined at the second end, the airflow channel has a first opening formed at the first end and a second opening formed at the second end. 
         [0007]    In one embodiment, the liquid guiding medium is partially received in the airflow channel via the second opening. 
         [0008]    In one embodiment, the heating element has a heating chamber, the liquid guiding medium has an insertion end and a heated end opposing to the insertion end, the insertion end is located inside the airflow channel, the heated end is located in the heating chamber. 
         [0009]    In one embodiment, the insertion end has a stepped shape, the liquid outlet is defined at inner sidewalls of the second end and the airflow channel, the insertion end is connected to the liquid outlet. 
         [0010]    In one embodiment, the liquid outlet has an annular shape and surrounds the airflow channel, the liquid guiding medium has an annular shape matching the liquid outlet, and the liquid guiding medium is received in the liquid outlet. 
         [0011]    In one embodiment, the heating element comprises a reflector and a heating tube fixed to the reflector, the heating tube and the liquid guiding medium forms a gap therebetween. 
         [0012]    In one embodiment, the cartridge includes opposed first and second connecting ends, the electronic cigarette further includes a mouthpiece and a power assembly, the mouthpiece is connected to the first connecting end, the second connecting end is connected to a first connection structure, the power assembly is connected to a second connection structure, the second connection structure is connected to the first connection structure, the heating element is electrically coupled to the power assembly via the fist connection structure and the second connection structure. 
         [0013]    In one embodiment, the first connection structure includes: a threaded sleeve that is conductive and fixed to the second connecting end; and a first electrode tube received in the threaded sleeve and insulated from threaded sleeve. 
         [0014]    In one embodiment, the second connection structure includes: a threaded post that is conductive and fixed to the power assembly, wherein the threaded post is located inside the threaded sleeve and is threadedly engaged with the threaded sleeve, the threaded post defines a shaft hole and has a rim portion fixed in the shaft hole; a second electrode tube received in the shaft hole and electrically coupled to the first electrode tube; and an insulating sleeve disposed between the rim portion and the second electrode tube, thereby insulating the threaded post from the second electrode tube. 
         [0015]    In one embodiment, the first connection structure includes: a threaded post that is conductive and fixed to the second connecting end, wherein the threaded post comprises a first cylinder and a second cylinder connected to the first cylinder, the first cylinder is provided with first and second spaced apart flanges on an outer side thereof, the first flange and the second flange form a first annular groove therebetween; a first electrode tube received in the threaded post; a first insulating sleeve disposed between the threaded post and the first electrode tube, thereby insulating the threaded post from the first electrode tube; and a resilient element disposed between the threaded post and an inner sidewall of the cartridge, wherein the resilient element comprises a ring and a bending portion connected to the ring, the ring is received in the first annular groove, the bending portion is located between the inner sidewall and the threaded post. 
         [0016]    In one embodiment, the second connection structure includes: a threaded sleeve that is conductive and fixed to the power assembly, the threaded sleeve comprises a threaded portion and a rim portion connected to the threaded portion, the threaded portion is connected to the second cylinder; a second electrode tube received in the threaded sleeve and connected to the first electrode tube; and a second insulating sleeve disposed between the rim portion and the second electrode tube, thus insulating the threaded post from the second electrode tube. 
         [0017]    In one embodiment, the ring has an inclined surface on a side thereof adjacent to the cartridge for guiding installation. 
         [0018]    In one embodiment, the ring is embedded in the first annular groove and is firmly attached to partial sidewall of the threaded post, such that the cartridge and the threaded post are firmly engaged. 
         [0019]    In one embodiment, the first insulating sleeve includes an annular insulating substrate and an insulating tube located on the insulating substrate, partial inner sidewall of the first cylinder is firmly attached to partial outer sidewall of the insulating tube. 
         [0020]    In one embodiment, the reservoir includes a liquid storage space and a liquid guiding tube, the liquid storage space has opposed first and second ends, and the liquid storage chamber for storing liquid, the liquid guiding tube extends out of the second end and is connected to the liquid guiding medium. 
         [0021]    In one embodiment, the liquid reservoir defines an airflow channel extending through the liquid storage space and the liquid guiding tube, the liquid outlet is defined on an inner sidewall of the airflow channel, and the liquid outlet is in fluid communication with the liquid storage chamber. 
         [0022]    In the aforementioned electronic cigarette, the liquid guiding medium can guide and restore the liquid from the reservoir. Since the gap is formed between the heating element and the liquid guiding medium, the heating element does not have to be in direct contact with the liquid guiding medium during heating the liquid guiding medium, thus avoiding contamination to the atomized liquid by the heating element, which is conducive to the health of user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a cross-sectional view of an electronic cigarette according to a first embodiment; 
           [0024]      FIG. 2  is an enlarged view of portion II of the electronic cigarette of  FIG. 1 ; 
           [0025]      FIG. 3  is a cross-sectional view of an electronic cigarette according to a second embodiment; 
           [0026]      FIG. 4  is a cross-sectional view of an electronic cigarette according to a third embodiment; 
           [0027]      FIG. 5  is a cross-sectional view of an electronic cigarette according to a fourth embodiment; 
           [0028]      FIG. 6  is a cross-sectional view of an electronic cigarette according to a fifth embodiment; 
           [0029]      FIG. 7  is a cross-sectional view of an electronic cigarette according to a sixth embodiment; 
           [0030]      FIG. 8  is a cross-sectional view of an electronic cigarette according to a seventh embodiment; 
           [0031]      FIG. 9  is an enlarged view of portion IX of the electronic cigarette of  FIG. 8 ; 
           [0032]      FIG. 10  is a cross-sectional view of an electronic cigarette according to a eighth embodiment; 
           [0033]      FIG. 11  is a cross-sectional view of an electronic cigarette according to a ninth embodiment; 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0034]    Embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings. The various embodiments of the invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0035]    It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, if an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
         [0036]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0037]    Referring to  FIG. 1  and  FIG. 2 , an electronic cigarette  10  according to a first embodiment includes a mouthpiece  11 , a cartridge  12 , an atomizing assembly  13 , a first connection structure  14 , a second connection structure  15 , a power assembly  16 , and an end cap  17 , which are subsequently disposed. The electronic cigarette  10  according to the illustrated embodiment has a substantially cylindrical shape. In alternative embodiments, the electronic cigarette  10  may have other shapes such as prism. 
         [0038]    The cartridge  12  includes a first connecting end  100  and a second connecting end  101  opposite to the first connecting end  100 . The mouthpiece  11  is disposed on the first connecting end  100 . 
         [0039]    The mouthpiece  11  is substantially funnel-shaped. The mouthpiece  11  has a bigger end  102  connected to the first connecting end  100 , and it has a smaller end  103  for user to suck. The funnel-shaped mouthpiece  11  is convenient for people to use. The mouthpiece  11  can be made of plastic materials, such as silica gel. The mouthpiece  11  has a vent  104  that allows air to pass through. The first connection structure  14  is connected to the second connecting end  101 . 
         [0040]    The atomizing assembly  13  is fixed in the cartridge  12 . The atomizing assembly  13  includes a reservoir  105 , a liquid guiding medium  106 , and a heating element  107 . 
         [0041]    The reservoir  105  has a liquid storage chamber  108  for storing liquid and a liquid outlet  109 . The liquid outlet  109  is in fluid communication with the liquid storage chamber  108  to allow the liquid to be drawn through the liquid outlet  109 . The reservoir  105  can be made of glass or high temperature plastics, such as PPS, PPA or LCP, PC, etc. In the illustrated embodiment, the reservoir  105  has a substantially tubular shape. In alternative embodiments, the reservoir  105  may have other shapes such as prism. 
         [0042]    The reservoir  105  defines an airflow channel  110  therein. The reservoir  105  includes a first end  111  and a second end  112  opposite to the first end  111 . The liquid outlet  109  is defined at inner surfaces of the second end  112  and the airflow channel  110 , i.e. the liquid outlet  109  is located at the junction between the inner surfaces of the second end  112  and the airflow channel  110 . The airflow channel  110  has a first opening  113  formed at the first end  111  and a second opening  114  formed at the second end  112 . The first opening  113  is positioned closer to the mouthpiece  11  than the second opening  114 . 
         [0043]    The liquid guiding medium  106  is made of porous liquid guilding materials and connected to the liquid outlet  109 . In the illustrated embodiment, the liquid guiding medium  106  is made of porous ceramic, preferably porous ceramic material with high thermal conductivity. The liquid guiding medium  106  is partially received in the airflow channel  110  via the second opening  114 . Specifically, the liquid guiding medium  106  includes an insertion end  115  and a heated end  116  opposing to the insertion end  115 . The insertion end  115  is located inside the airflow channel  110 , the insertion end  115  has a stepped shape and is connected to the liquid outlet  109 , such that the liquid from the reservoir  105  can be guided by the insertion end  115  to the liquid guiding medium  106  through the liquid outlet  109 . The liquid guiding medium  106  defines a T-shaped aperture  117  in fluid communication with the airflow channel  110 . It should be understood that, in alternative embodiment, the liquid guiding medium  106  can be made of refractory porous glass, porous graphite, porous fibers, and other porous materials. Because the reservoir  105  uses high temperature plastics or glass as a liquid storage medium instead of fire cotton, and uses porous ceramic material as the liquid guiding medium instead of high silica fiber rope, the problem of producing bacteria due to the long term contact between the fire cotton/high silica fiber rope and the liquid can be avoided. In addition, the fire cotton and the high silica fiber rope tends to absorb impurities during use of the electronic cigarette, which results in unsmooth of the liquid guiding. The electronic cigarette  10  according to the present embodiment can overcome this deficiency and achieve a smooth liquid guiding and is healthy to use. 
         [0044]    The heating element  107  is fixed in the cartridge  12 , and a gap  18  is formed between the heating element  107  and the liquid guiding medium  106 . The heating element  107  can heat the liquid guiding medium  106  in a non-contact way. In the illustrated embodiment, the heating element  107  is an electronic pulse heating device and has a heating chamber  118  and an electrode portion  119 . The heating chamber  118  and the electrode portion  119  are located at opposite ends o the heating element  107 . The heated end  116  of the liquid guiding medium  106  is received inside the heating chamber  118 . The electrode portion  119  is electrically coupled to the first connection structure  14 . The heating element  107  defines a through hole  120  therein to allow the airflow to pass through. The T-shaped aperture  117  is in fluid communication with the through hole  120  via the heating chamber  118 . During assembly of the conventional electronic cigarette, due to individual skills of each worker, the number of turns of the heat wire and the space between each turn is different, which causes the final taste of each electronic cigarette is different. However, in the illustrated embodiment, since no heating wire is used, the aforementioned problem is overcome. 
         [0045]    In the illustrated embodiment, the first connection structure  14  includes a conductive threaded sleeve  121  and a first electrode tube  122 . The threaded sleeve  121  is fixed to the second connecting end  101  of the cartridge  12 . The first electrode tube  122  is received in the threaded sleeve  121  and is insulated from the threaded sleeve  121 . In the illustrated embodiment, an annular latching groove  123  is provided on an outer sidewall of the first electrode tube  122 . It should be understood that, the first electrode tube  122  can be fixed to an inner sidewall of the second connecting end  101  by some fastening elements (not shown), such as fixing rod or fixing block, etc. The electrode of the electrode portion  119  is electrically coupled to the threaded sleeve  121  and the first electrode tube  122 , respectively. In the illustrated embodiment, the threaded sleeve  121  is made of gold-plated brass, which has a good conductivity with excellent plasticity for easy shaping. In alternative embodiment, the threaded sleeve  121  can be made of other conductive materials. The first electrode tube  122  and the threaded sleeve  121  can be made of the same or different materials. 
         [0046]    The second connection structure  15  is connected to the power assembly  16  and is connected to the first connection structure  14 . The heating element  107  is electrically coupled to the power assembly  16  via the first connection structure  14  and the second connection structure  15 . 
         [0047]    In the illustrated embodiment, the second connection structure  15  includes a conductive threaded post  124 , a second electrode tube  125 , and an insulating sleeve  126 . The threaded post  124  is fixed to the power assembly  16 , and the threaded post  124  is located inside the threaded sleeve  121  and is threadedly engaged with the threaded sleeve  121 . The threaded post  124  defines a shaft hole  127  therein and includes a first cylinder  128  and a second cylinder  129  connected to the first cylinder  128 . The shaft hole  127  extends through the first cylinder  128  and the second cylinder  129 . The first cylinder  128  is provided with a rim portion  130  in the shaft hole  127 . The maximum diameter of the first cylinder  128  is greater than that of the second cylinder  129 . The second electrode tube  125  is received in a part of the shaft hole in the first cylinder  128  and is connected to the first electrode tube  122 . In the illustrated embodiment, the second electrode tube  125  defines an inserting hole  131  and forms an annular rib  132  inside the inserting hole  131 . The annular rib  132  can be engaged in the latching groove  123 , such connection method as that can ensure a better electrical connection between the first electrode tube  122  and the second electrode tube  125  and improve the structural stability. Both of the first electrode tube  122  and the second electrode tube  125  defines a vent (not shown) along an axis of the electronic cigarette  10 . In the illustrated embodiment, the threaded post  124  is made of the same materials as that of the threaded sleeve  121 , e.g. gold-plated brass. In alternative embodiments, the threaded post  124  can be made of other conductive materials. The second electrode tube  125  and the threaded post  124  can be made of the same or different materials. 
         [0048]    The insulating sleeve  126  is disposed between the rim portion  130  and the second electrode tube  125 , such that the threaded post  124  is insulated from the second electrode tube  125 , and a firmly engagement is formed between the threaded post  124  and the second electrode tube  125 . A structural stability of the threaded post  124  and the second electrode tube  125  is increased accordingly. The insulating sleeve  126  can be made of insulation materials, such as silicone, rubber, etc. 
         [0049]    The power assembly  16  includes a switch  133  and a battery  134 . The switch  133  is disposed on the shaft hole of the second cylinder  129 . The switch  133  includes a button  135 , a contact pad  136 , and a conducting plate  137 . The second cylinder  129  defines a button hole  138  in communication with the shaft hole  127 , the button  135  can be exposed from the button hole  138 , thus facilitating pressing by the user. The button  135  has a first contacting point  139  corresponding to the contact pad  136 , and the first contacting point  139  is electrically coupled to the threaded post  124 . The contact pad  136  is electrically coupled to one electrode of the battery  134 . The contact pad  136  has a second contacting point  140  corresponding to the first contacting point  139 . When the button  135  is pressed by external force, the first contacting point  139  is in contact with the second contacting point  140 , such that the threaded post  124  is in electrical connection with the electrode of the battery  134 . When the external force applied to the button  135  is removed, the button  135  can restore to its initial position by a resilient element (not shown) of the switch  133 , such that the first contacting point  139  is disengaged from the second contacting point  140 . 
         [0050]    The conducting plate  137  is coupled to the second electrode tube  125  and the other electrode of the battery  134 , thus achieving an electrical connection between the first electrode tube  122  and the other electrode of the battery  134 . In the illustrated embodiment, the battery  134  is a battery integrated with controlled IC. 
         [0051]    The end cap  17  and the second connection structure  15  are positioned on opposed ends of the power assembly  16 . The end cap  17  defines an air intake (not shown) to allow the air to be drawn into the electronic cigarette  10 . Entering from the air intake of the end cap  17 , the air flow can pass through the shaft hole  127  of the threaded post  124 , the vent of the first electrode tube  122  and the second electrode tube  125 , the through hole  120  of the heating element, then enter the T-shaped aperture  117 . The airflow can carry the atomized liquid to pass through the airflow channel  110  and flow out from the vent  104  of the mouthpiece  11 , thus it can be inhaled by the user. 
         [0052]    In the aforementioned electronic cigarette  10 , the liquid guiding medium  106  can guide and restore the liquid from the reservoir  105 . Since the gap  18  is formed between the heating element  107  and the liquid guiding medium  106 , the heating element does not have to be in direct contact with the liquid guiding medium  106  during heating the liquid guiding medium  106 , thus avoiding contamination to the atomized liquid by the heating element  107 , which is conducive to the health of user. 
         [0053]    Referring to  FIG. 3 , an electronic cigarette  20  is provided according to the second embodiment. The electronic cigarette  20  has a structure similar to that of the electronic cigarette  10  of the first embodiment, and it differs from electronic cigarette  10  in that, the reservoir  201 , the liquid guiding medium  202 , and the heating element  203  of the second embodiment are different from the first embodiment. 
         [0054]    The liquid outlet  205  of the reservoir  201  is defined on the second end  206  of the reservoir  201 , and the liquid outlet  205  has an annular shape surrounding the airflow channel  207 . The liquid guiding medium  202  has an annular shape matching the liquid outlet  205 , and the liquid guiding medium  202  is received in the liquid outlet  205 . 
         [0055]    The heating element  203  includes a reflector  208 , a heating tube  209 , and an electrode portion  210 . The heating tube  209  and the electrode portion  210  are fixed to opposing sides of the reflector  208 , and a gap  200  is formed between the heating tube  209  and the liquid guiding medium  202 . 
         [0056]    The reflector  208  is shaped as a spherical crown, which can radiate the heat generated by the heating tube  209  towards the liquid guiding medium  202 . The reflector  208  is fixed to a rim  211  formed on the inner sidewall of the cartridge  22 . The rim  211  is provided with a vent (not shown), the airflow can flow from the gap between the reflector  208  and the cartridge  22  into the gap  200  between the heating tube  209  and the liquid guiding medium  202  via the vent, such that the atomized liquid can be brought into the airflow channel  207  via the airflow. In alternative embodiments, the reflector  208  can have other shapes, as long as it can radiate the heat generated by the heating tube  209  towards the liquid guiding medium  202 . In the illustrated embodiment, since the reflector  208  can focus the heat to the liquid guiding medium  202 , the utilization of heat is improved. The connection type between the electrode portion  210  and the power assembly  23  is similar to that between the electrode portion  119  and the power assembly  16  of the first embodiment, which will not be described in further details. 
         [0057]    In the illustrated embodiment, the heating tube  209  is an infrared heating tube. In alternative embodiments, the heating tube can be a photoelectric heating tube and other heating tube. 
         [0058]    Referring to  FIG. 4 , an electronic cigarette  30  is provided according to the third embodiment. The electronic cigarette  30  has a structure similar to that of the electronic cigarette  10  of the first embodiment, and it differs from electronic cigarette  10  in that, the reservoir  301 , the liquid guiding medium  302 , and the heating element  303  of the third embodiment are different from the first embodiment. 
         [0059]    The reservoir  301  has a liquid storage space  304  and a liquid guiding tube  305 . The liquid storage space  304  has a first end  306 , a second end  307  opposite to the first end  306 , and a liquid storage chamber  308  for storing liquid. The liquid guiding tube  305  extends out of the second end  307 . The reservoir  301  defines an airflow channel  309 , which extends through the liquid storage space  304  and the liquid guiding tube  305 . The airflow channel  309  defines a liquid outlet  316  on an inner sidewall thereof, which is in fluid communication with the liquid storage chamber  308 . 
         [0060]    The liquid guiding medium  302  has a substantially columnar shape. The liquid guiding medium  302  defines a middle through hole  310  therein, and one end of the liquid guiding tube  305  is fixed inside the middle through hole  310 . 
         [0061]    In the illustrated embodiment, the heating element  303  is a microwave heating device. The heating element  303  is fixed inside the cartridge  32  and is connected to the reservoir  301 . The heating element  303  has a heating chamber  311 , a coil  312 , and an electrode portion  313 . The heating chamber  311  and the electrode portion  313  are located on opposing sides of the coil  312 . One electrode of the electrode portion  313  is electrically coupled to the threaded sleeve  314 , and the other electrode of the electrode portion  313  is electrically coupled to the first electrode tube  315 . 
         [0062]    The liquid guiding medium  302  and the liquid guiding tube  305  is received in the heating chamber  311 , and a gap  300  is formed between the liquid guiding medium  302  and the heating element  303 . The heating element  303  is connected to the reservoir  301 , thus the heating chamber  311  can be well surrounded with less heat loss, and the liquid guiding medium  302  can absorb more heat to improve the efficiency of the electric heat and atomizing effect. In addition, the liquid guiding medium  302  is received in the heating chamber  311  as a whole, such that the whole liquid guiding medium  302  can absorb heat directly, thus improving the atomizing effect. 
         [0063]    Referring to  FIG. 5 , an electronic cigarette  40  is provided according to the fourth embodiment. The electronic cigarette  40  includes a mouthpiece  41 , a cartridge  42 , an atomizing assembly  43 , a power assembly  44 , and an end cap  45 , which are subsequently disposed. In the illustrated embodiment, a tube body of the cartridge  42  and a tube body of the power assembly  44  are integrally formed, thus forming a housing  45  of the electronic cigarette. The housing  45  is substantially an elongated hollow cylinder. The mouthpiece  41  and the end cap  45  are located at opposing ends of the housing  45 . 
         [0064]    The atomizing assembly  43  is fixed in the cartridge  42 . The atomizing assembly  43  includes a reservoir  401 , a liquid guiding medium  402 , and a heating element  403 . 
         [0065]    The reservoir  401  has a liquid storage space  404  and a liquid guiding tube  405 . The liquid storage space  404  has a first end  406 , a second end  407  opposite to the first end  406 , and a liquid storage chamber  408  for storing liquid. The liquid guiding tube  405  extends out of the second end  407  and is connected to the liquid guiding medium  402 . The reservoir  401  defines an airflow channel  409 , which extends through the liquid storage space  404  and the liquid guiding tube  405 . The reservoir  401  can be made of glass or high temperature plastics, such as PPS, PPA or LCP, PC, etc. In the illustrated embodiment, the liquid storage space  404  and the liquid guiding tube  405  have a substantially tubular shape. In alternative embodiments, the liquid storage space  404  and the liquid guiding tube  405  may have other shapes such as prism. 
         [0066]    The airflow channel  409  defines a liquid outlet  410  on an inner sidewall thereof, which is in fluid communication with the liquid storage chamber  408 . 
         [0067]    The liquid guiding medium  402  is made of porous liquid guiding materials and connected to liquid guiding tube  405 , so as to be connected to the liquid outlet  410 . In the illustrated embodiment, the liquid guiding medium  402  is made of porous ceramic, preferably porous ceramic material with high thermal conductivity. The liquid guiding medium  402  includes an insertion end  411  and a heated end  412  opposing to the insertion end  411 . The insertion end  411  is located inside the airflow channel  409 , the insertion end  411  has a stepped shape and is connected to the liquid outlet  410 , such that the liquid from the reservoir  401  can be guided by the insertion end  411  to the liquid guiding medium  402  through the liquid outlet  410 . The liquid guiding medium  402  defines a T-shaped aperture  413  in fluid communication with the airflow channel  409 . It should be understood that, in alternative embodiment, the liquid guiding medium  402  can be made of refractory porous glass, porous graphite, porous fibers, and other porous materials. 
         [0068]    The heating element  403  is fixed inside the cartridge  42 , and a gap  400  is formed between the heating element  403  and the liquid guiding medium  402 . In the illustrated embodiment, the heating element  403  is an electronic pulse heating device, which includes a heating chamber  414  and an electrode portion  415 . The heating chamber  414  and the electrode portion  415  are located at opposing ends of the heating element  403 . The liquid guiding medium  402  has a heated end  412  located in the heating chamber  414 . The heating element  403  defines a through hole  416  therein for allowing airflow to pass through. The T-shaped aperture  413  is in fluid communication with through hole  416  via the heating chamber  414 . 
         [0069]    The power assembly  44  includes a battery  417 . In the illustrated embodiment, the battery  417  is a battery integrated with controlled IC. One electrode of the electrode portion  415  is coupled to one electrode of the battery  417 , and the other electrode of the electrode portion  415  is coupled to the other electrode of the battery  417 . 
         [0070]    The end cap  45  defines an air intake (not shown) to allow the air to be drawn into the electronic cigarette  40 . Entering from the air intake of the end cap  45 , the airflow can pass through the gap of the power assembly  44  and the through hole  416  of the heating element  403 , then enter the T-shaped aperture  117 . The airflow can carry the atomized liquid to flow out from the vent  418  of the mouthpiece  41 , thus it can be inhaled by the user. 
         [0071]    The electronic cigarette  40  according the present embodiment omits the connection structure between the cartridge and the power assembly, thus simplifying the structure and reducing the cost. 
         [0072]    Referring to  FIG. 6 , an electronic cigarette  50  is provided according to the fifth embodiment. The electronic cigarette  50  has a structure similar to that of the electronic cigarette  40  of the fourth embodiment, and it differs from electronic cigarette  40  in that, the reservoir  501 , the liquid guiding medium  502 , and the heating element  503  of the fifth embodiment are different from the fourth embodiment. 
         [0073]    The reservoir  501  has a liquid storage chamber  504  for storing liquid and a liquid outlet  505 . The liquid outlet  505  is in fluid communication with the liquid storage chamber  504  to allow the liquid to be drawn through the liquid outlet  505 . The reservoir  501  can be made of glass or high temperature plastics, such as PPS, PPA or LCP, PC, etc. In the illustrated embodiment, the reservoir  501  has a substantially tubular shape. In alternative embodiments, the reservoir  501  may have other shapes such as prism. 
         [0074]    The reservoir  501  defines an airflow channel  506  therein. The reservoir  501  includes a first end  507  and a second end  508  opposite to the first end  507 . The liquid outlet  505  is defined at the second end  508 . The airflow channel  506  has a first opening  509  formed at the first end  507  and a second opening  510  formed at the second end  508 . Specifically, the liquid outlet  505  is defined on the second end  508 , and the liquid outlet  505  has an annular shape surrounding the airflow channel  506 . The liquid guiding medium  502  has an annular shape matching the liquid outlet  505 , and the liquid guiding medium  502  is received in the liquid outlet. The liquid guiding medium  502  is made of porous liquid guiding materials. In the illustrated embodiment, the liquid guiding medium  502  is made of porous ceramic, preferably porous ceramic material with high thermal conductivity. It should be understood that, in alternative embodiment, the liquid guiding medium  502  can be made of refractory porous glass, porous graphite, porous fibers, and other porous materials. 
         [0075]    The heating element  503  includes a reflector  511 , a heating tube  512 , and an electrode portion  513 . The heating tube  512  and the electrode portion  513  are fixed to opposing sides of the reflector  511  respectively, and a gap  500  is formed between the heating tube  512  and the liquid guiding medium  502 . 
         [0076]    The reflector  511  is shaped as a spherical crown, which can radiate the heat generated by the heating tube  512  towards the liquid guiding medium  502 . The reflector  511  is fixed in the cartridge  52 . In alternative embodiments, the reflector  511  can have other shapes, as long as it can radiate the heat generated by the heating tube  512  towards the liquid guiding medium  502 . One electrode of the electrode portion  513  is electrically coupled to an electrode of the battery  514  of the power assembly  54 , and the other electrode of the electrode portion  513  is electrically coupled to the other electrode of the battery  514  of the power assembly  54 . In the illustrated embodiment, the reflector  511  can focus the radiation of heat to the liquid guiding medium  502 , thereby increasing the usage efficiency of heat. 
         [0077]    In the illustrated embodiment, the heating tube  512  is an infrared heating tube. In alternative embodiments, the heating tube  512  can be other heating tubes such as photoelectric heating tube. 
         [0078]    Referring to  FIG. 7 , an electronic cigarette  60  is provided according to the sixth embodiment. The electronic cigarette  60  has a structure similar to that of the electronic cigarette  50  of the fifth embodiment, and it differs from electronic cigarette  50  in that, the reservoir  601 , the liquid guiding medium  602 , and the heating element  603  of the electronic cigarette  60  are different from the fifth embodiment. 
         [0079]    In the illustrated embodiment, the liquid outlet  604  of the reservoir  601  is defined at inner surfaces of the second end  605  of the reservoir  601  and the airflow channel  606 , i.e. the liquid outlet  604  is located at the junction between the inner surfaces of the second end  605  and the airflow channel  606 . The airflow channel  606  has a first opening  608  formed at the first end  607  of the reservoir  601  and a second opening  609  formed at the second end  605 . 
         [0080]    The liquid guiding medium  602  is made of porous liquid guiding materials and connected to the liquid outlet  604 . In the illustrated embodiment, the liquid guiding medium  602  is made of porous ceramic, preferably porous ceramic material with high thermal conductivity. The liquid guiding medium  602  is partially received in the airflow channel  606  via the second opening  609 . Specifically, the liquid guiding medium  602  includes an insertion end  610  and a heated end  611  opposing to the insertion end  610 . The insertion end  610  is located inside the airflow channel  606 , the insertion end  610  has a stepped shape and is connected to the liquid outlet  604 , such that the liquid from the reservoir  601  can be guided by the insertion end  610  to the liquid guiding medium  602  through the liquid outlet  604 . The liquid guiding medium  602  defines a linear aperture  612  therein, the linear aperture  612  extends through two opposing ends of the liquid guiding medium  602 . The linear aperture  612  is in fluid communication with the airflow channel  606 . Since the linear aperture  612  is in direct fluid communication with a through hole of the heating element  603  and the airflow channel  606 , the airflow can flow more smoothly, and more liquid in the liquid guiding medium  602  will be atomized, thus further improving the atomizing effect and efficiency. It should be understood that, in alternative embodiment, the liquid guiding medium  602  can be made of refractory porous glass, porous graphite, porous fibers, and other porous materials. 
         [0081]    The heating element  603  is a microwave heating device. The heating element  603  is fixed inside the cartridge  62  and is connected to the reservoir  601 . The heating element  603  has a heating chamber  613 , a coil  614 , and an electrode portion  615 . The heating chamber  613  and the electrode portion  615  are located on opposing sides of the coil  614 . The heated end  611  of the liquid guiding medium  602  is received in the heating chamber  613 , and a gap  600  is formed between the heated end  611  and the heating element  603 . Since the heating element  603  is connected to the reservoir  601 , the heating chamber  613  can be well surrounded with less heat loss, and the liquid guiding medium  602  can absorb more heat to improve the efficiency of the electric heat and atomizing effect. 
         [0082]    The coil  614  is electrically coupled to the electrode portion  615 . One electrode of the electrode portion  615  is electrically coupled to an electrode of the battery  616  of the power assembly  64 , and the other electrode of the electrode portion  615  is electrically coupled to the other electrode of the battery  616 , such that the power assembly  64  can provide power to the coil  614  via the electrode portion  615  to generate microwave, thus heating the liquid guiding medium  602 . 
         [0083]    Referring to  FIG. 8  and  FIG. 9 , an electronic cigarette  70  is provided according to the seventh embodiment. The electronic cigarette  70  has a structure similar to that of the electronic cigarette  10  of the first embodiment, and it differs from electronic cigarette  10  in that, the mouthpiece  71 , the first connection structure  72 , the second connection structure  73  and the power assembly  74  of the electronic cigarette  70  are different from the first embodiment. 
         [0084]    The mouthpiece  71  has a columnar shape. The first connection structure  72  includes a conductive threaded post  701 , a first electrode tube  702 , a first insulating sleeve  703 , and a resilient element  704 . 
         [0085]    The resilient element  704  is disposed between the threaded post  701  and the cartridge, thus the threaded post  701  and the cartridge are firmly engaged. The first insulating sleeve  703  is disposed between the threaded post  701  and the first electrode tube  702 , thus the threaded post  701  and the first electrode tube  702  are insulated from each other and are firmly engaged. 
         [0086]    The threaded post  701  is fixed to the second connecting end of the cartridge and is connected to an electrode of the heating element. The threaded post  701  includes a first cylinder  705  and a second cylinder  706  connected to the first cylinder  705 . The first cylinder  705  has a maximum outer diameter which is substantially equal to the inner diameter of the cartridge, such that the outer sidewall of the first cylinder  705  is firmly attached to the inner sidewall of the cartridge to form a close engagement. The second cylinder  706  is provided with an external thread on an outer side thereof for coupling the second connection structure  73 . The second cylinder  706  has a smaller outer diameter than the inner diameter of the cartridge. The first cylinder  705  and the cartridge are closely engaged via the resilient element  704 . 
         [0087]    The first cylinder  705  is provided with first and second spaced apart flanges  707 ,  708 . The first flange  707  has a greater outer diameter than that of the second flange  708 . A first annular groove  709  is formed between the first flange  707  and the second flange  708 . A second annular groove  710  is formed between the second flange  708  and an inner sidewall of the cartridge. The threaded post  701  is conductive. In the illustrated embodiment, the threaded post  701  is made of gold-plated brass. The threaded post of this material has an excellent conductivity, as well as good plasticity for easy shaping. In alternative embodiments, the threaded post  701  can be made of other conductive materials. 
         [0088]    The resilient element  704  includes a ring  711  and a bending portion  712  connected to the ring  711 . The ring  711  has a circular shape. The bending portion  712  extends perpendicularly from an edge of the ring  711 . The ring  711  is received in the first annular groove  709  formed between the first flange  707  and the second flange  708 . The ring  711  has an inclined surface  713  on a side thereof adjacent to the cartridge for guiding installation. An angle formed by the inclined surface  713  and the inner surface of the cartridge is ranged from 5° to 30°. A gap for guiding installation is formed between the resilient element  704  and the inner surface of the cartridge due to the angle formed by the inclined surface  713  and the inner surface of the cartridge. In the illustrated embodiment, the ring  711  is embedded in the first annular groove  709  and is in close contact with partial inner sidewall of the cartridge, such that the cartridge forms a close engagement with the threaded post  701 . The bending portion  712  is located between the cartridge and the first cylinder  705 . During assembly of the resilient element  704 , the resilient element  704  will be deformed by pressing, and the deformed partial bending portion  712  is received in the second annular groove  710  formed between the inner sidewall of the cartridge and the second flange  708 . The resilient element  704  is made of rubber. Specifically, the resilient element  704  can be made of silicone rubber, fluorine rubber, fluorosilicone rubber. 
         [0089]    The first insulating sleeve  703  includes an annular insulating substrate  714  and an insulating tube  715  located on the insulating substrate  714 . Partial inner sidewall of the first cylinder  705  is firmly attached to partial outer sidewall of the insulating tube  715  and the insulating substrate  714 . The first insulating sleeve  703  is disposed between the threaded post  701  and the first electrode tube  702 , thereby insulating the threaded post  701  from the first electrode tube  702 , and a close engagement is formed between the threaded post  701  and the first electrode tube  702 . A structural stability of the threaded post  701  and the second electrode tube  702  is increased accordingly. The first insulating sleeve  703  can be made of insulation materials, such as silicone, rubber, etc. 
         [0090]    The first electrode tube  702  includes a first conductive tube  716  and a ring portion  717  positioned on the first conductive tube  716 . The first conductive tube  716  has a first contact end  718  and a second contact end  719 , which are located on opposing sides of the ring portion  717 . The first contact end  718  is connected to the other electrode of the heating element. The inner sidewall of the first insulating sleeve  703  is attached to partial outer sidewall of the first electrode tube  702 . The ring portion  717  has a greater cross-sectional area with respect to the first conductive tube  716 , thus a contact area between the ring portion  717  and the first insulating sleeve  703  is increased, thereby improving the stability between the first conductive tube  716  and the first insulating sleeve  703 . The threaded post  701  serves as one electrode, while the first conductive tube  716  serves as the other electrode, which is electrically coupled to the power assembly  74  and the heating element of the electronic cigarette  70 . In the illustrated embodiment, the first conductive tube  716  is made of the same material as that of the threaded post  701 , i.e. gold-plated brass. In alternative embodiments, the first conductive tube  716  can be made of other metal materials. 
         [0091]    The second connection structure  73  includes a conductive threaded sleeve  720 , a second electrode tube  721 , and an insulating sleeve  722 . 
         [0092]    The threaded sleeve  720  is fixed to the power assembly  74  and is connected to one electrode of the power assembly  74 . The threaded sleeve  720  includes a threaded portion  723  and a rim portion  724  connected to the threaded portion  723 . The threaded portion  723  has an internal thread, which can be engaged with the external thread of the second cylinder  706 , so as to connect the threaded portion  723  to the second cylinder  706 , such that the threaded post  701  is engaged with the threaded sleeve  720  to achieve the electrical connection. The threaded sleeve  720  is made of gold-plated brass, which has a good conductivity with excellent plasticity for easy shaping. In alternative embodiment, the threaded sleeve  720  can be made of other conductive materials. 
         [0093]    The second electrode tube  721  is connected to the other electrode of the power assembly  74 . The second electrode tube  721  is received in the threaded sleeve  720  and is connected to the second contact end  719  to form an electrical connection with the first electrode tube  716 . Specifically, the second electrode tube  721  includes an annular-shaped base  725  and a second conductive tube  726  connected to the base  725 . 
         [0094]    The second conductive tube  726  extends through the second insulating sleeve  722 . The base  725  has a greater cross-sectional area with respect to the second conductive tube  726 , thus a contact area between the base  725  and the second insulating sleeve  722  is increased, thereby improving the stability between the second electrode tube  721  and the second insulating sleeve  722 . In the illustrated embodiment, the second electrode tube  721  is made of the same material as that of the threaded sleeve  720 , i.e. gold-plated brass. In alternative embodiments, the second electrode tube  721  can be made of other metal materials. 
         [0095]    The second insulating sleeve  722  is located between the rim portion  724  and the second electrode tube  721 , thus insulating the threaded sleeve  720  from the second electrode tube  721 . The second insulating sleeve  722  defines a latching groove  727  on an outer peripheral thereof. The rim of the rim portion  724  is firmly engaged in the latching groove  727 , thereby further improving the binding stability between the second electrode tube  721  and the threaded sleeve  720 . 
         [0096]    In the illustrated embodiment, an air intake  728  is formed between the threaded sleeve  720  and the first cylinder  705 , and the first connection structure  72  further defines a gas hole (not shown, e.g. the one radially extends through the second cylinder  706  and the first electrode tube  716 ) in fluid communication with the air intake  728 . The gas hole is in fluid communication with a through hole  729  of the heating element. 
         [0097]    In the illustrated embodiment, since the ring  711  of the resilient element  704  is received in the annular groove  709  of the threaded post  701 , and the bending portion  712  extends perpendicularly from an edge of the ring  711  and is clamped between the threaded post  701  and the cartridge, the resilient element  704  can be firmly attached to partial sidewall of the threaded post  701 . Therefore the contact area between the resilient element  704  and the threaded post  701  is increased to the largest extent, and a more firmly pressure is provided, such that the threaded post  701  is more firmly connected to the cartridge. 
         [0098]    Because the switch is omitted in the power assembly  74 , the electronic cigarette  70  has a simple structure and a lower cost. In addition, the electronic cigarette  70  further includes an airflow sensor assembly (not shown), which can control on and off of the electrical connection between the heating element and the power assembly  74 . When the user inhales at the mouthpiece, the external airflow can enter the electronic cigarette  70  through the air intake  728 . The airflow sensor assembly can sense the size of the airflow and control the heating element to work or stop working. The airflow sensor can render different atomizing effect according to the different intensity of respiration of the user, thus increasing the user&#39;s experiences. 
         [0099]    Referring to  FIG. 10 , an electronic cigarette  80  is provided according to the eighth embodiment. The electronic cigarette  80  has a structure similar to that of the electronic cigarette  70  of the seventh embodiment, and it differs from electronic cigarette  70  in that, the reservoir  801 , the liquid guiding medium  802 , and the heating element  803  of the electronic cigarette  80  according to the eighth embodiment are different from the seventh embodiment. 
         [0100]    The liquid outlet  804  of the reservoir  801  is defined on the second end  805  of the reservoir  801 , and the liquid outlet  804  has an annular shape surrounding the airflow channel  806 . The liquid guiding medium  802  has an annular shape matching the liquid outlet, and the liquid guiding medium  802  is received in the liquid outlet  205 . 
         [0101]    The heating element  803  includes a reflector  807 , a heating tube  808 , and an electrode portion  809 . The heating tube  808  and the electrode portion  809  are fixed to opposing sides of the reflector  807 , and a gap  800  is formed between the heating tube  808  and the liquid guiding medium  802 . 
         [0102]    The reflector  807  is shaped as a spherical crown, which can radiate the heat generated by the heating tube  808  towards the liquid guiding medium  802 . The reflector  807  is fixed to an inner sidewall of the cartridge  82  by, for example, a spaced arranged fixing element or a fixing rod (not shown). The airflow can flow from the gap between the reflector  807  and the cartridge  82  into the gap  800  between the heating tube  808  and the liquid guiding medium  802 , such that the atomized liquid can be brought into the airflow channel  806  via the airflow. In alternative embodiments, the reflector  807  can have other shapes, as long as it can radiate the heat generated by the heating tube  808  towards the liquid guiding medium  802 . In the illustrated embodiment, since the reflector  807  can focus the heat to the liquid guiding medium  802 , the utilization of heat is improved. 
         [0103]    In the illustrated embodiment, the heating tube  808  is an infrared heating tube. In alternative embodiments, the heating tube  808  can be a photoelectric heating tube and other heating tube. 
         [0104]    Referring to  FIG. 11 , an electronic cigarette  90  is provided according to the ninth embodiment. The electronic cigarette  90  has a structure similar to that of the electronic cigarette  70  of the seventh embodiment, and it differs from electronic cigarette  70  in that, the liquid guiding medium  901  and the heating element  803  of the electronic cigarette  90  according to the ninth embodiment are different from the seventh embodiment. 
         [0105]    The liquid guiding medium  901  defines a linear aperture  903  therein, the linear aperture  903  extends through two opposing ends of the liquid guiding medium  901 . The linear aperture  903  is in fluid communication with the airflow channel  904 . 
         [0106]    The heating element  902  is a microwave heating device. The heating element  902  is fixed inside the cartridge  92  and is connected to the reservoir  900 . The heating element  902  has a heating chamber  905 , a coil  906 , and an electrode portion  907 . The heating chamber  905  and the electrode portion  907  are located on opposing sides of the coil  906 . The heated end  908  of the liquid guiding medium  901  is received in  t he heating chamber  905 , and a gap  910  is formed between the heated end  908  and the heating element  902 . Since the heating element  902  is connected to the reservoir  900 , the heating chamber  905  can be well surrounded with less heat loss, and the liquid guiding medium  901  can absorb more heat to improve the efficiency of the electric heat and atomizing effect. 
         [0107]    The electrode portion  907  is electrically coupled to the first connection structure, for example, one electrode of the electrode portion  907  is connected to the conductive post, and the other electrode of the electrode portion  907  is connected to first conductive tube. 
         [0108]    The heating element  902  defines a through hole  909  therein for allowing the air to flow. The linear aperture  903  is in direct fluid communication with the through hole  909  and the airflow channel  904 , such that the airflow can flow more smoothly, and more liquid in the liquid guiding medium  901  will be atomized, thus further improving the atomizing effect and efficiency. 
         [0109]    Although the description is illustrated and described herein with reference to certain embodiments, the description is not intended to be limited to the details shown. Modifications may be made in the details within the scope and range equivalents of the claims.