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 toFIG. 1, a piezoelectricsealing cap assembly300 including apiezoelectric sealing cap100 according to an exemplary embodiment of the present invention may include apiezoelectric sealing cap100 and areagent bottle200. 
- Detailed exemplary embodiments of thepiezoelectric sealing cap100 will be described hereinafter. The piezoelectricsealing cap assembly300 according to an exemplary embodiment of the present invention may have all of the detailed characteristics of each embodiment of thepiezoelectric sealing cap100. 
- Thereagent bottle200, 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 thereagent bottle200 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. 
- Thereagent bottle200 may include anopening220 into which fluid to be stored is introduced, and the opening220 may include abottle neck210. 
- Thepiezoelectric sealing cap100 may be inserted into thebottle neck210, thepiezoelectric sealing cap100 for sealing the content of thereagent bottle200. 
- Herein, the shape of thepiezoelectric sealing cap100 may correspond to the shape of the inner circumferential surface of thebottle neck210, wherein the inner circumferential surface of thebottle neck210 may have a circular shape or a polygonal shape. 
- In addition, thebottle neck210 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 thereagent bottle200. 
- 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, andFIG. 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 toFIGS. 2 and 3, when a driving voltage is applied to thepiezoelectric sealing cap100 according to an exemplary embodiment of the present invention by apower supply unit250, the diameter of thepiezoelectric sealing cap100 may be reduced to a smaller diameter than the diameter of the opening220 of thereagent bottle200. 
- In this configuration, the principle of displacement generation of thepiezoelectric sealing cap100 will be described later with reference toFIGS. 4 to 7, and the relationship between thepiezoelectric sealing cap100 and the opening220 of thereagent bottle200 will be described hereinafter. 
- When a driving voltage is applied to thepiezoelectric sealing cap100 by thepower supply unit250, the diameter of thepiezoelectric sealing cap100 is reduced to be smaller than the diameter of the inner circumferential surface of thebottle neck210 of thereagent bottle200. 
- Therefore, thepiezoelectric sealing cap100 may be easily inserted into thebottle neck210. 
- Even after being inserted, thepiezoelectric sealing cap100 may be moved up and down in thebottle neck210 and after being moved to a desired position to be fixed, it may block the driving voltage from thepower supply unit250. 
- At this time, a separate switch (not shown) may be provided so as to block the driving voltage from thepower supply unit250 and the driving voltage may be freely applied or blocked by the switch. 
- When a driving voltage from thepower supply unit250 is blocked, the diameter of thepiezoelectric sealing cap100 is increased and subsequently, closely attached to the inner circumferential surface of thebottle neck210 of thereagent bottle200. 
- Therefore, the content of thereagent bottle200 may be sealed by thepiezoelectric sealing cap100 and the described process may be reversely performed when the sealing thereof is released. 
- In other words, when the driving voltage blocked by thepiezoelectric sealing cap100 is applied again, the diameter of thepiezoelectric sealing cap100 is reduced, thereby being easily pulled out from thebottle neck210. 
- 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, andFIGS. 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 toFIGS. 5 and 6, thepiezoelectric sealing cap100 according to the present invention may include apiezoelectric element150 and a sealingpart130. 
- Thepiezoelectric element150 may include anupper electrode120a, alower electrode120b, and apiezoelectric body110, wherein theupper electrode120aand thelower electrode120bmay provide a driving voltage to thepiezoelectric body110 to generate displacement of thepiezoelectric element150. 
- Thepiezoelectric body110 may be formed as piezoelectric fluid having viscosity is solidified between theupper electrode120aand thelower electrode120b, and thepiezoelectric body110 is a material capable of converting electrical energy into mechanical energy or mechanical energy into electrical energy. 
- In other words, thepiezoelectric body110 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. 
- Thepiezoelectric body110 may include a lead zirconate titanate (Pb(Zr, Ti)03: PZT) ceramic and have a perovskite crystal structure. 
- In addition, thepiezoelectric body110 may require a polling process so as to have the characteristics as described above. 
- Referring toFIGS. 4A through 4C, when DC field260 is generated by applying voltage to the upper and lower electrodes (not shown) positioned on the upper and lower portions of thepiezoelectric body110, adjacent directions of a dipole gradually correspond to each other due to the DC field260. 
- In other words, a process of applying the DC field260 to thepiezoelectric body110 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 thepiezoelectric body110 in an initial state, wherein polarization of thepiezoelectric body110 in an initial state has a random arrangement. 
- In thepiezoelectric body110 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 thepiezoelectric body110 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 inFIG. 4B, polarization may be induced by applying the DC field260 to the upper and lower electrodes (not shown) of thepiezoelectric body110 in an initial state. 
- In other words, when the DC field260 is applied to thepiezoelectric body110 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 theelectric field direction115. 
- Thereafter, the applied DC field260 is removed. The internal structure of thepiezoelectric body110 from which the DC field260 is removed is shown inFIG. 4C. 
- It can be appreciated fromFIG. 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 inFIG. 4A. 
- In other words, even though the DC field260 is applied to thepiezoelectric body110 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 theremnant strain115 and remnant polarization are generated in thepiezoelectric body110 due to the polling. 
- In this case, theremnant strain115 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 thepiezoelectric body110 as a whole. 
- Thepiezoelectric body110, subjected to the polling as described above, becomes more dense and has electrical characteristics, thereby making it possible to perform the function of thepiezoelectric sealing cap100. 
- Thepiezoelectric sealing cap100 may include apiezoelectric element150 configured of the upper andlower electrodes120aand120bas described above and a sealingpart130. 
- Herein, the upper and thelower electrodes120aand120bareelectrode layers120 positioned on the upper portion and the lower portion of thepiezoelectric body110. The upper andlower electrodes120aand120bmay be evenly positioned over the upper portion and the lower portion of thepiezoelectric body110 so that the driving voltage of thepower supply unit250 is evenly applied to thepiezoelectric body110. 
- Theelectrode layer120 may be made of at least any one of platinum (Pt), gold (Au), silver (Ag), nickel (Ni), titanium (Ti), copper (Cu), and the like. Theelectrode layer120 may be formed on the upper surface and the lower surface of thepiezoelectric body110 by inkjet printing, E-beam evaporation, chemical vapor deposition (CVD), sputtering, screen printing, plating, or the like. 
- Referring toFIG. 5, thepiezoelectric sealing cap100 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 thepower supply unit250 is connected to theupper electrode120ain which negative (−) charges are dense, and a negative (−) terminal of thepower supply unit250 is connected to thelower electrode120bin which positive (+) charges are dense. 
- When thepower supply unit250 is electrically connected to theelectrode layer120, thepiezoelectric element150 is expanded due to attractive force between the internal charges of thepiezoelectric element150 and the applied voltage from thepower supply unit250. 
- In other words, the width of thepiezoelectric sealing cap100 becomes smaller than the inner circumferential surface of thebottle neck210 of thereagent bottle200, thereby being easily inserted into the bottle neck210 (seeFIG. 2). 
- However, a driving terminal of thelower electrode120bof theelectrode layer120 may be projected to theupper electrode120a, in consideration of the characteristics of thepiezoelectric sealing cap100, and may be projected upward by penetrating through the sealingpart130 described below. 
- When thepiezoelectric sealing cap100 is inserted into thebottle neck210 and then the driving voltage from thepower supply unit250 is blocked, the width of thepiezoelectric element150 is gradually increased, thereby finally making it possible to completely seal the bottle neck210 (seeFIG. 3). 
- In other words, when the driving voltage to thepiezoelectric element150 is blocked, attractive force between the internal charge of thepiezoelectric element150 and the driving voltage is lost and thus the width of thepiezoelectric element150 is increased, thereby sealing thebottle neck210. 
- Therefore, it is possible to prevent highly volatile materials or harmful materials in thereagent bottle200 from being discharged and easily insert thepiezoelectric sealing cap100 into thebottle neck210 of thereagent bottle200. 
- In addition, when thepiezoelectric sealing cap100 is to be detached from thebottle neck210, it may be performed by reversely conducting the processes. In other words, it may be performed only by applying the driving voltage from thepower supply unit250 to theelectrode layer120 of thepiezoelectric element150. 
- In this configuration, thepiezoelectric sealing cap100 may include the sealingpart130. The sealingpart130 is formed to surround thepiezoelectric element150, thereby making it possible to seal thebottle neck210 when thepiezoelectric element150 is inserted into thebottle neck210. 
- Herein, the sealingpart130 may be formed to cover the outer side of thepiezoelectric element150 and be elastically deformed according to the displacement of thepiezoelectric element150. 
- In addition, the sealingpart130 may be made of rubber in order to have elasticity. As described above, the driving terminal may penetrate through the sealingpart130 so that the driving terminal of theelectrode layer120 at one side of thepiezoelectric element150 is projected upward. 
- When thepiezoelectric sealing cap100 is inserted into thebottle neck210, the sealingpart130 can completely seal thebottle neck210 and surround the upper surface of thepiezoelectric sealing cap100 to be opened as shown inFIG. 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 thepiezoelectric element150 by polling; however, the inverse case is also obvious. 
- In other words, as the positive (+) terminal and the negative (−) terminal of thepower supply unit250 are inversely connected, the internal charges of thepiezoelectric element150 and the driving voltage of thepower supply unit250 generate repulsive force, such that thepiezoelectric sealing cap100 may be expanded. 
- However, in this case, when thebottle neck210 is sealed, thepower supply unit250 is connected and when the content of thereagent bottle200 is stored, thepower supply unit250 should be always connected. Therefore, it may be preferable that thebottle neck210 is sealed by attractive force. 
- As described above, when highly volatile materials or harmful materials are stored in thereagent bottle200 using electrical characteristics of thepiezoelectric body110, thepiezoelectric sealing cap100 according to the present invention can improve sealing force of thereagent bottle200 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.