Abstract:
A powder plasma processing apparatus is disclosed. The powder plasma processing apparatus is a powder plasma processing apparatus of a circular surface discharge plasma module, and the apparatus includes a plate-like electrode layer serving as an external surface of the circular surface discharge plasma module, an insulating layer disposed on an internal surface of the plate-like electrode layer, and a plasma generating electrode disposed on the insulating layer, wherein the circular surface discharge plasma module rotates, an alternating voltage is applied to the plasma generating electrode and the plate-like electrode layer to generate plasma around the plasma generating electrode, and a powder for plasma processing is processed by the plasma within the circular surface discharge plasma module.

Description:
BACKGROUND 
     1. Field of the Invention 
       [0001]    The present invention relates to a powder plasma processing apparatus, and more particularly, to a powder plasma processing apparatus that uniformly processes a powder using a circular surface discharge plasma module. 
       2. Discussion of Related Art 
       [0002]    Plasma is an ionized gas. When a gas consisting of atoms or molecules is excited using energy, plasma consisting of electrons, decomposed gases, photons, and the like is generated. This plasma is widely used for surface treatment of objects to be processed (e.g., a substrate or the like). 
         [0003]    Pulsed corona discharge and dielectric film discharge are well known as techniques of generating plasma. Pulsed corona discharge is a technique that uses a high-voltage pulse power supply to generate plasma, and dielectric film discharge is a technique in which a dielectric is formed on at least one of two electrodes and a power having a frequency of several Hz to several tens of Hz is applied to the two electrodes to generate plasma. 
         [0004]    A dielectric barrier discharge (DBD) technique is employed as the representative dielectric film discharge. In a plasma processing apparatus using the DBD technique, when an object to be processed is disposed between plate electrodes and an inert gas is used to cause the dielectric film discharge to occur, plasma is generated and then brought into contact with a surface of the object to be processed, thereby processing the surface of the object to be processed. 
         [0005]    However, in the plasma processing apparatus described above, since the object to be processed is disposed between the plate electrodes, although it is not difficult to process one surface or both surfaces when the object to be processed is a plate-like member, it is difficult to process an entire surface of the object to be processed when the object to be processed is a powder. A plasma processing apparatus for processing the object to be processed is thus required when the object to be processed is a powder. 
         [0006]    A plasma processing apparatus of the prior art for processing an object to be processed when the object to be processed is a powder is disclosed in an application filed with the title “Tubular plasma processing apparatus” as Korean application No. of 10-2012-0078234 by the present inventors. According to this literature, it is possible to perform surface treatment on a powder but difficult to perform uniform processing on the powder. 
         [0007]    The present inventors have recognized the problems of the prior art and solved the problems of the conventional plasma processing apparatus through research. Further, the present inventors have developed a powder plasma processing apparatus that can provide a method of controlling a contact time between an object to be processed and plasma and efficiently performing uniform processing on a powder. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is directed to a powder plasma processing apparatus of a circular surface discharge plasma module, the apparatus including: a plate-like electrode layer serving as an external surface of the circular surface discharge plasma module; an insulating layer disposed on an internal surface of the plate-like electrode layer; and a plasma generating electrode disposed on the insulating layer, wherein the circular surface discharge plasma module rotates, an alternating voltage is applied to the plasma generating electrode and the plate-like electrode layer to generate a plasma around the plasma generating electrode, and a powder for plasma processing is processed by the plasma within the circular surface discharge plasma module. 
         [0009]    For example, a plurality of the plasma generating electrodes are arranged on the insulating layer at intervals in the circumferential direction of the surface discharge plasma module, and extend in the longitudinal direction of the surface discharge plasma module. 
         [0010]    As another example, a plurality of the plasma generating electrodes are arranged on the insulating layer at intervals in the longitudinal direction of the surface discharge plasma module, and extend in the circumferential direction of the surface discharge plasma module. 
         [0011]    According to an embodiment of the present invention, a high voltage is applied to the plate-like electrode layer, and the plasma generating electrode is a ground electrode. 
         [0012]    According to another embodiment of the present invention, a high voltage is applied to the plasma generating electrode, and the plate-like electrode layer is a ground electrode. 
         [0013]    The apparatus includes a driving unit. The driving unit is configured to rotate the circular surface discharge plasma module while the circular surface discharge plasma module is in a horizontal state. The specific method in which the circular surface discharge plasma module is rotated is not a characteristic of the present invention, and it will be recognized that various methods of rotating the circular surface discharge plasma module may be employed for the present invention. 
         [0014]    The driving unit includes a rotational speed control unit. The rotational speed control unit is configured to control the speed at which the driving unit rotates the circular surface discharge plasma module. It will be recognized that various methods of controlling the speed at which the driving unit rotates the circular surface discharge plasma module may be employed for the present invention. 
         [0015]    According to the powder plasma processing apparatus of the present invention, it is possible to perform uniform processing on the powder and to control the time that the powder spends in contact with the plasma, thereby allowing efficient powder processing to be performed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which: 
           [0017]      FIG. 1  is a perspective view illustrating a surface discharge plasma module of a powder plasma processing apparatus according to the present invention; 
           [0018]      FIG. 2  is a side view of  FIG. 1 ; and 
           [0019]      FIG. 3  is a perspective view illustrating another example of the arrangement in which ground electrodes of the powder plasma processing apparatus according to the present invention are arranged 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0020]    A powder plasma processing apparatus according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The present invention may be subjected to many changes and have several forms, and specific embodiments thereof are illustrated in the drawings and described in detail in the specification. However, it will be understood that the present invention is not intended to be limited to the specific forms set forth herein, and all changes, equivalents, and substitutions included in the technical scope and spirit of the present invention are included. Referring to the drawings, similar reference numerals are used to refer to similar components. In the accompanying drawings, the dimensions of the structures may be exaggerated for clarity. 
         [0021]    Terms such as first, second, and the like may be used to describe various components, but these components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another component. For instance, a first component may be referred to as a second component, or similarly, a second component may be referred to as a first component, without departing from the scope of the present invention. 
         [0022]    Terms used herein are intended to only explain specific embodiments of the present invention, not to limit the invention. The singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that the terms “comprises” or “have,” when used in this specification, are intended to specify the presence of stated features, integers, steps, operations, components, a combination thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, or a combination thereof. 
         [0023]    Unless otherwise defined herein, all terms used in the present invention including technical or scientific terms have the same meanings as terms that are generally understood by those skilled in the art related to the field of the present invention. The same terms as those that are defined in a general dictionary should be understood to have the same meanings as contextual meanings of the related art. Unless the terms are explicitly defined in the present invention, the terms should not be interpreted with ideal or excessively formal meanings. 
         [0024]      FIG. 1  is a perspective view illustrating a surface discharge plasma module of a powder plasma processing apparatus according to the present invention, and  FIG. 2  is a side view of  FIG. 1   
         [0025]    Referring to  FIGS. 1 and 2 , a circular surface discharge plasma module  110  is employed as the powder plasma processing apparatus according to an embodiment of the present invention. The surface discharge plasma module  110  includes a plate-like electrode layer  111 , an insulating layer  112 , and plasma generating electrodes  113 . 
         [0026]    The plate-like electrode layer  111  forms an outer surface of the circular surface discharge plasma module  110 . 
         [0027]    The insulating layer  112  insulates the plate-like electrode layer  111  from the plasma generating electrodes  113 , and the insulating layer  112  is formed at an inner surface side of the plate-like electrode layer  111 . For example, the insulating layer  112  may be formed of a material such as MgO, MgF 2 , LiF, CaF 2 , alumina, glass, ceramic, magnesium oxide, and so forth. 
         [0028]    A plurality of the plasma generating electrodes  113  are arranged on the insulating layer  112 , and plasma is generated around the plasma generating electrodes  113 . For example, the plasma generating electrodes  113  may be in the form of a bar and may protrude on the insulating layer  112 . For example, the arrangement of the plasma generating electrodes  113  may be such that they are arranged at intervals in the circumferential direction of the circular surface discharge plasma module  110  or the plasma generating electrodes  113  may extend in the longitudinal direction of the surface discharge plasma module  110 . As another example, referring to  FIG. 3 , the plasma generating electrodes  113  may be arranged at intervals in the longitudinal direction of the circular surface discharge plasma module  110  or the plasma generating electrodes  113  may extend in the circumferential direction of the circular surface discharge plasma module  110 . 
         [0029]    According to an embodiment of the present invention, a high voltage is applied to the plate-like electrode layer  111 , and the plasma generating electrodes  113  are ground electrodes. 
         [0030]    According to another embodiment of the present invention, the plate-like electrode layer  111  is a ground electrode, and a high voltage is applied to the plasma generating electrodes  113 . 
         [0031]    In this surface discharge plasma module  110 , an alternating voltage is applied from the plasma power supply  120  to the plasma generating electrodes  113  and the plate-like electrode layer  111 , and a plasma reaction gas is injected, thereby generating the plasma around the plasma generating electrodes  113 . For example, a gas containing oxygen such as O 2  or N 2 O, a gas containing fluorine such as CF 4  or SF 6 , a gas containing chlorine such as Cl 2  or BCl 3 , and an inert gas such as Ar or N 2  may be used alone or in combination as the plasma reaction gas. 
         [0032]    In addition, both sides of the surface discharge plasma module  110  in the longitudinal direction may be opened, and a powder may be supplied and withdrawn (collected) through the opened sides. The surface treatment is performed on the powder by means of the plasma while the surface discharge plasma module  110  rotates. 
         [0033]    The present invention includes a driving unit for rotating the surface discharge plasma module  110 . Although not shown, the driving unit may have a form for rotating the surface discharge plasma module  110 , for example, driving means such as a driving motor may be connected to the surface discharge plasma module  110 . The driving unit is not specifically limited as long as it can rotate the surface discharge plasma module  110 . 
         [0034]    The driving unit includes a rotational speed control unit. The rotational speed control unit is configured to control the speed at which the circular surface discharge plasma module  110  is rotated. Although not shown, for example, the rotational speed control unit may be in the form of a control box or a programmable logic controller (PLC). The rotational speed control unit is not specifically limited to this configuration. When the rotational speed of the surface discharge plasma module  110  is adjusted, the time that the powder spends in contact with the plasma or the number of times the powder comes in contact with the plasma is adjusted. 
         [0035]    Hereinafter, the procedure of processing the powder using the powder plasma processing apparatus according to the present invention will be briefly described. 
         [0036]    The powder is injected into the surface discharge plasma module  110 . 
         [0037]    An alternating voltage is applied from the plasma power supply  120  to the plate-like electrode layer  111  and the plasma generating electrodes  113 , and a reaction gas is injected, thereby generating the plasma around the plasma generating electrodes  113 . 
         [0038]    The surface discharge plasma module  110  is rotated by the driving unit. 
         [0039]    When the surface discharge plasma module  110  is rotated, the powder within the surface discharge plasma module  110  rises and falls in the rotational direction of the rotating surface discharge plasma module  110 . This procedure is repeated while the surface discharge plasma module  110  is rotated. In this case, the powder is in contact with the plasma. 
         [0040]    The rotational speed of the surface discharge plasma module  110  may be adjusted if necessary. 
         [0041]    When the powder plasma processing apparatus according to the embodiment of the present invention is employed, the surface discharge plasma module  110  is circular, and the powder is processed while the surface discharge plasma module  110  is rotated, thereby allowing the powder to be uniformly processed. 
         [0042]    In addition, since the speed at which the circular surface discharge plasma module is rotated is adjusted, the time that the powder spends in contact with the plasma can be controlled. 
         [0043]    It will be apparent to those skilled in the art that various modifications can be made to the above-described exemplary embodiments of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover all such modifications provided they come within the scope of the appended claims and their equivalents. 
       REFERENCE NUMERAL 
       [0044]      110  Surface discharge plasma module 
         [0045]      111  Plate-like electrode layer 
         [0046]      112  Insulating layer 
         [0047]      113  Plasma generating electrode 
         [0048]      120  Plasma power supply