Patent Publication Number: US-2012037588-A1

Title: Piezoelectric sealing cap and assembly including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority of Korean Patent Application No. 10-2010-0078490 filed on Aug. 13, 2010, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a piezoelectric sealing cap and an assembly including the same, and more particularly, to a piezoelectric sealing cap completely sealing highly volatile materials, harmful materials, or the like in a reagent bottle, and an assembly including the same. 
     2. Description of the Related Art 
     When a fluid such as an experimental reagent for research, a beverage or the like is stored, it should be blocked from being discharged to the outside. In particular, in the case of highly volatile materials or harmful materials, function of blocking the outflow thereof to the outside is one of the most important factors in the storage thereof. 
     In other words, in the case of chemical materials such as an experimental reagent, the sealing function of the content is considered to be the most important factor in the storage thereof and therefore a cap plays a very important role in a reagent bottle. 
     In the related art, a cap of a reagent bottle is formed to have an internal space for receiving an opening, so the reagent bottle may receive the opening, wherein an outer circumferential surface of the opening is fastened to an inner circumferential surface of the cap by a screw connection method. 
     In addition to the method as described above, when premium content such as wine is stored, the content is prevented from being discharged to the outside using the elasticity of a cork stopper. 
     However, the cap according to the related art using the screw connection has disadvantages in that it is difficult to completely connect the screw connection parts and it is also difficult to manufacture a female screw thread and a male screw thread according to precise numerical values. 
     In addition, in the case of the screw connection, it is weakly sealed when rotation force is weak. When rotation force is strong in order to strongly seal the screw, a large torque is required when releasing the sealing. 
     In addition, in the case of the cap using the cork, it requires a separate cap opener since it uses the elasticity of the cork. Further, it is very difficult to reseal the cap after the cap has been opened. 
     Therefore, in the case that highly volatile materials or harmful materials are stored, there is an urgent demand for research into a cap, the sealing of which can be simply released, while completely maintaining the overall sealing thereof, that is, a sealing cap of a reagent bottle. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention provides a piezoelectric sealing cap that improves the sealing ability of a reagent bottle in which highly volatile materials or the like are stored to prevent a danger due to the outflow of the content therefrom and simply releases the sealing thereof, and an assembly including the same. 
     A piezoelectric sealing cap according to a preferred embodiment of the present invention includes: a piezoelectric element generating displacement by a driving voltage; and a sealing part formed to surround the piezoelectric element and sealing a bottle neck when the piezoelectric element is inserted into the bottle neck. 
     The sealing part may be formed to cover the outer side of the piezoelectric element and to be elastically deformed according to the displacement of the piezoelectric element. 
     The sealing part may be made of rubber so as to have elasticity. 
     The piezoelectric element may include electrode layers formed on an upper surface and a lower surface thereof and when a driving voltage is applied to the electrode layers, the displacement of the piezoelectric element may be generated due to attractive or repulsive force between the internal charges of the piezoelectric element and the driving voltage. 
     A driving terminal of the electrode layer at one side may be projected to the electrode layer at the other side in order to apply a driving voltage to the electrode layer. 
     The driving terminal of the electrode layer at one side may be formed by penetrating through the sealing part. 
     A piezoelectric sealing cap assembly according to another preferred embodiment of the present invention includes: a piezoelectric element generating displacement by a driving voltage; a sealing part formed to surround the piezoelectric element and sealing a bottle neck when the piezoelectric element is inserted into the bottle neck; and a power supply unit applying the driving voltage to the piezoelectric element so that the width of the piezoelectric element is smaller than the width of the bottle neck due to attractive force between the internal charges of the piezoelectric element and the driving voltage. 
     The sealing part may be formed to cover the outer side of the piezoelectric element and be elastically deformed according to the displacement of the piezoelectric element. 
     The sealing part may be made of rubber so as to have elasticity. 
     When the driving voltage to the piezoelectric element is blocked, attractive force between the internal charges of the piezoelectric element and the driving voltage may be lost to increase the widths of the piezoelectric element and the sealing part. 
     The piezoelectric element may include electrode layers formed on an upper surface and a lower surface thereof, and a driving voltage may be applied to the electrode layers. 
     A driving terminal of the electrode layer at one side may be projected to the electrode layer at the other side in order to apply a driving voltage to the electrode layer. 
     The driving terminal of the electrode layer at one side may be formed by penetrating through the sealing part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view schematically showing a piezoelectric sealing cap assembly including a piezoelectric sealing cap according to an exemplary embodiment of the present invention; 
         FIG. 2  is an exploded perspective view schematically showing a piezoelectric sealing cap assembly including a piezoelectric sealing cap according to an exemplary embodiment of the present invention; 
         FIG. 3  is a perspective view schematically showing a structure in which a bottle neck is sealed by a piezoelectric sealing cap according to an exemplary embodiment of the present invention; 
         FIGS. 4A through 4C  are cross-sectional views schematically showing a polling of a piezoelectric sealing cap according to an exemplary embodiment of the present invention; 
         FIG. 5  is a cross-sectional view schematically showing relationship between a piezoelectric element of a piezoelectric sealing cap according to an exemplary embodiment of the present invention and a driving voltage thereof; 
         FIG. 6  is a cross-sectional view schematically showing relationship between a piezoelectric element of a piezoelectric sealing cap according to another exemplary embodiment of the present invention and a driving voltage thereof; and 
         FIG. 7  is a perspective view schematically showing relationship between a piezoelectric element of a piezoelectric sealing cap according to an exemplary embodiment of the present invention and a driving voltage thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, it should be noted that the spirit of the present invention is not limited to the embodiments set forth herein and those skilled in the art and understanding the present invention can easily accomplish retrogressive inventions or other embodiments included in the spirit of the present invention by the addition, modification, and removal of components within the same spirit, but those are construed as being included in the spirit of the present invention. 
     Further, throughout the drawings, the same or similar reference numerals will be used to designate the same components or like components having the same functions in the scope of the similar idea. 
       FIG. 1  is a perspective view schematically showing a piezoelectric sealing cap assembly including a piezoelectric sealing cap according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , a piezoelectric sealing cap assembly  300  including a piezoelectric sealing cap  100  according to an exemplary embodiment of the present invention may include a piezoelectric sealing cap  100  and a reagent bottle  200 . 
     Detailed exemplary embodiments of the piezoelectric sealing cap  100  will be described hereinafter. The piezoelectric sealing cap assembly  300  according to an exemplary embodiment of the present invention may have all of the detailed characteristics of each embodiment of the piezoelectric sealing cap  100 . 
     The reagent bottle  200 , which is a bottle in which chemicals are stored, may be a bottle in which highly volatile materials or harmful materials are put and stored. 
     However, it is to be noted beforehand that the reagent bottle  200  is not limited to a bottle in which chemicals are stored but may be replaced by a container in which a general fluid such as a beverage, water, or the like, drunk in daily life, is stored. 
     The reagent bottle  200  may include an opening  220  into which fluid to be stored is introduced, and the opening  220  may include a bottle neck  210 . 
     The piezoelectric sealing cap  100  may be inserted into the bottle neck  210 , the piezoelectric sealing cap  100  for sealing the content of the reagent bottle  200 . 
     Herein, the shape of the piezoelectric sealing cap  100  may correspond to the shape of the inner circumferential surface of the bottle neck  210 , wherein the inner circumferential surface of the bottle neck  210  may have a circular shape or a polygonal shape. 
     In addition, the bottle neck  210  may be a hole having a predetermined width but is not always limited thereto and may have a width that gradually increases or decreases in a direction towards a lower end of the reagent bottle  200 . 
       FIG. 2  is an exploded perspective view schematically showing a piezoelectric sealing cap assembly including a piezoelectric sealing cap according to an exemplary embodiment of the present invention, and  FIG. 3  is a perspective view schematically showing a structure in which a bottle neck is sealed by a piezoelectric sealing cap according to an exemplary embodiment of the present invention. 
     Referring to  FIGS. 2 and 3 , when a driving voltage is applied to the piezoelectric sealing cap  100  according to an exemplary embodiment of the present invention by a power supply unit  250 , the diameter of the piezoelectric sealing cap  100  may be reduced to a smaller diameter than the diameter of the opening  220  of the reagent bottle  200 . 
     In this configuration, the principle of displacement generation of the piezoelectric sealing cap  100  will be described later with reference to  FIGS. 4 to 7 , and the relationship between the piezoelectric sealing cap  100  and the opening  220  of the reagent bottle  200  will be described hereinafter. 
     When a driving voltage is applied to the piezoelectric sealing cap  100  by the power supply unit  250 , the diameter of the piezoelectric sealing cap  100  is reduced to be smaller than the diameter of the inner circumferential surface of the bottle neck  210  of the reagent bottle  200 . 
     Therefore, the piezoelectric sealing cap  100  may be easily inserted into the bottle neck  210 . 
     Even after being inserted, the piezoelectric sealing cap  100  may be moved up and down in the bottle neck  210  and after being moved to a desired position to be fixed, it may block the driving voltage from the power supply unit  250 . 
     At this time, a separate switch (not shown) may be provided so as to block the driving voltage from the power supply unit  250  and the driving voltage may be freely applied or blocked by the switch. 
     When a driving voltage from the power supply unit  250  is blocked, the diameter of the piezoelectric sealing cap  100  is increased and subsequently, closely attached to the inner circumferential surface of the bottle neck  210  of the reagent bottle  200 . 
     Therefore, the content of the reagent bottle  200  may be sealed by the piezoelectric sealing cap  100  and the described process may be reversely performed when the sealing thereof is released. 
     In other words, when the driving voltage blocked by the piezoelectric sealing cap  100  is applied again, the diameter of the piezoelectric sealing cap  100  is reduced, thereby being easily pulled out from the bottle neck  210 . 
       FIGS. 4A through 4C  are cross-sectional views schematically showing a polling of a piezoelectric sealing cap according to an exemplary embodiment of the present invention, and  FIGS. 5 through 7  are cross-sectional views and a perspective view schematically showing relationship between a piezoelectric element of a piezoelectric sealing cap according to an exemplary embodiment of the present invention and a driving voltage thereof. 
     Referring to  FIGS. 5 and 6 , the piezoelectric sealing cap  100  according to the present invention may include a piezoelectric element  150  and a sealing part  130 . 
     The piezoelectric element  150  may include an upper electrode  120   a , a lower electrode  120   b , and a piezoelectric body  110 , wherein the upper electrode  120   a  and the lower electrode  120   b  may provide a driving voltage to the piezoelectric body  110  to generate displacement of the piezoelectric element  150 . 
     The piezoelectric body  110  may be formed as piezoelectric fluid having viscosity is solidified between the upper electrode  120   a  and the lower electrode  120   b , and the piezoelectric body  110  is a material capable of converting electrical energy into mechanical energy or mechanical energy into electrical energy. 
     In other words, the piezoelectric body  110  may be made of a material in which polarization is induced in the material when mechanical pressure is applied from the outside or mechanical deformation is generated due to external electric field. 
     The piezoelectric body  110  may include a lead zirconate titanate (Pb(Zr, Ti)03: PZT) ceramic and have a perovskite crystal structure. 
     In addition, the piezoelectric body  110  may require a polling process so as to have the characteristics as described above. 
     Referring to  FIGS. 4A through 4C , when DC field  260  is generated by applying voltage to the upper and lower electrodes (not shown) positioned on the upper and lower portions of the piezoelectric body  110 , adjacent directions of a dipole gradually correspond to each other due to the DC field  260 . 
     In other words, a process of applying the DC field  260  to the piezoelectric body  110  and then removing it again is called ‘polling’. The polling will be described hereinafter. 
       FIG. 4A  is a cross-sectional view showing an internal structure of the piezoelectric body  110  in an initial state, wherein polarization of the piezoelectric body  110  in an initial state has a random arrangement. 
     In the piezoelectric body  110  in an initial state, which is a polycrystal, the inside of each crystalline grain is generally divided into several polarizations having different polarization directions, the entirety of the polarizations in this state are offset so as not to be represented to the outside. 
     In the piezoelectric body  110  in an initial state, polarization is not entirely formed. As a result, when mechanical pressure is applied from the outside, polarization may not be induced in the material or mechanical deformation may not be generated due to an external electric field. 
     Therefore, as shown in  FIG. 4B , polarization may be induced by applying the DC field  260  to the upper and lower electrodes (not shown) of the piezoelectric body  110  in an initial state. 
     In other words, when the DC field  260  is applied to the piezoelectric body  110  in an initial state, the polarization direction in the crystal is polarized according to the DC field direction and at the same time, the length of the crystalline grain is lengthened in the electric field direction  115 . 
     Thereafter, the applied DC field  260  is removed. The internal structure of the piezoelectric body  110  from which the DC field  260  is removed is shown in  FIG. 4C . 
     It can be appreciated from  FIG. 4C  that the length of the crystalline grain is changed to be lengthened in the polarization shaft as compared to that in an initial state shown in  FIG. 4A . 
     In other words, even though the DC field  260  is applied to the piezoelectric body  110  in an initial state and then is removed, the crystalline grains are not returned to their original states and the majority of the crystalline grains maintain a polarized state. 
     This is the reason that the remnant strain  115  and remnant polarization are generated in the piezoelectric body  110  due to the polling. 
     In this case, the remnant strain  115  implies that a state of the crystalline grain is changed due to the polling and the remnant polarization implies that polarization is formed in the applied field direction. 
     Therefore, negative (−) charges and positive (+) charges are captured on the upper portion and the lower portion of the piezoelectric body  110  as a whole. 
     The piezoelectric body  110 , subjected to the polling as described above, becomes more dense and has electrical characteristics, thereby making it possible to perform the function of the piezoelectric sealing cap  100 . 
     The piezoelectric sealing cap  100  may include a piezoelectric element  150  configured of the upper and lower electrodes  120   a  and  120   b  as described above and a sealing part  130 . 
     Herein, the upper and the lower electrodes  120   a  and  120   b  are electrode layers  120  positioned on the upper portion and the lower portion of the piezoelectric body  110 . The upper and lower electrodes  120   a  and  120   b  may be evenly positioned over the upper portion and the lower portion of the piezoelectric body  110  so that the driving voltage of the power supply unit  250  is evenly applied to the piezoelectric body  110 . 
     The electrode layer  120  may be made of at least any one of platinum (Pt), gold (Au), silver (Ag), nickel (Ni), titanium (Ti), copper (Cu), and the like. The electrode layer  120  may be formed on the upper surface and the lower surface of the piezoelectric body  110  by inkjet printing, E-beam evaporation, chemical vapor deposition (CVD), sputtering, screen printing, plating, or the like. 
     Referring to  FIG. 5 , the piezoelectric sealing cap  100  according to the present invention is formed with polarizations through the polling as described above, and negative (−) charges and positive (+) charges may be separately formed on the upper portion and the lower portion thereof as a whole. 
     At this time, a positive (+) terminal of the power supply unit  250  is connected to the upper electrode  120   a  in which negative (−) charges are dense, and a negative (−) terminal of the power supply unit  250  is connected to the lower electrode  120   b  in which positive (+) charges are dense. 
     When the power supply unit  250  is electrically connected to the electrode layer  120 , the piezoelectric element  150  is expanded due to attractive force between the internal charges of the piezoelectric element  150  and the applied voltage from the power supply unit  250 . 
     In other words, the width of the piezoelectric sealing cap  100  becomes smaller than the inner circumferential surface of the bottle neck  210  of the reagent bottle  200 , thereby being easily inserted into the bottle neck  210  (see  FIG. 2 ). 
     However, a driving terminal of the lower electrode  120   b  of the electrode layer  120  may be projected to the upper electrode  120   a , in consideration of the characteristics of the piezoelectric sealing cap  100 , and may be projected upward by penetrating through the sealing part  130  described below. 
     When the piezoelectric sealing cap  100  is inserted into the bottle neck  210  and then the driving voltage from the power supply unit  250  is blocked, the width of the piezoelectric element  150  is gradually increased, thereby finally making it possible to completely seal the bottle neck  210  (see  FIG. 3 ). 
     In other words, when the driving voltage to the piezoelectric element  150  is blocked, attractive force between the internal charge of the piezoelectric element  150  and the driving voltage is lost and thus the width of the piezoelectric element  150  is increased, thereby sealing the bottle neck  210 . 
     Therefore, it is possible to prevent highly volatile materials or harmful materials in the reagent bottle  200  from being discharged and easily insert the piezoelectric sealing cap  100  into the bottle neck  210  of the reagent bottle  200 . 
     In addition, when the piezoelectric sealing cap  100  is to be detached from the bottle neck  210 , it may be performed by reversely conducting the processes. In other words, it may be performed only by applying the driving voltage from the power supply unit  250  to the electrode layer  120  of the piezoelectric element  150 . 
     In this configuration, the piezoelectric sealing cap  100  may include the sealing part  130 . The sealing part  130  is formed to surround the piezoelectric element  150 , thereby making it possible to seal the bottle neck  210  when the piezoelectric element  150  is inserted into the bottle neck  210 . 
     Herein, the sealing part  130  may be formed to cover the outer side of the piezoelectric element  150  and be elastically deformed according to the displacement of the piezoelectric element  150 . 
     In addition, the sealing part  130  may be made of rubber in order to have elasticity. As described above, the driving terminal may penetrate through the sealing part  130  so that the driving terminal of the electrode layer  120  at one side of the piezoelectric element  150  is projected upward. 
     When the piezoelectric sealing cap  100  is inserted into the bottle neck  210 , the sealing part  130  can completely seal the bottle neck  210  and surround the upper surface of the piezoelectric sealing cap  100  to be opened as shown in  FIG. 6 . 
     The above embodiment describes a case in which negative (−) charges and positive (+) charges are separately formed on the upper portion and the lower portion of the piezoelectric element  150  by polling; however, the inverse case is also obvious. 
     In other words, as the positive (+) terminal and the negative (−) terminal of the power supply unit  250  are inversely connected, the internal charges of the piezoelectric element  150  and the driving voltage of the power supply unit  250  generate repulsive force, such that the piezoelectric sealing cap  100  may be expanded. 
     However, in this case, when the bottle neck  210  is sealed, the power supply unit  250  is connected and when the content of the reagent bottle  200  is stored, the power supply unit  250  should be always connected. Therefore, it may be preferable that the bottle neck  210  is sealed by attractive force. 
     As described above, when highly volatile materials or harmful materials are stored in the reagent bottle  200  using electrical characteristics of the piezoelectric body  110 , the piezoelectric sealing cap  100  according to the present invention can improve sealing force of the reagent bottle  200  to prevent damage due to the leakage of the content and be simply released after being sealed. 
     As set forth above, according to the piezoelectric sealing cap and an assembly including the same according to exemplary embodiments of the invention, highly volatile materials, harmful materials, or the like, can be completely sealed, thereby making it possible to secure stability. 
     In addition, the size of the piezoelectric sealing cap is changed by a driving voltage, thereby making it possible to easily seal the cap or release it after being sealed. 
     While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.