Patent Publication Number: US-8119955-B2

Title: Device for preventing leakage of microwave for microwave oven

Description:
TECHNICAL FIELD 
     The present invention relates to a microwave oven, and more particularly, to a device for preventing microwave leakage for a microwave oven capable of preventing microwave applied into a cooking chamber from leaking to the outside through the neighborhood of a porous portion in which a heater assembly is installed. 
     BACKGROUND ART 
     In general, a microwave oven is a cooking appliance for cooking food by applying microwave generated from a variety of electric parts into a cooking chamber. Recently, a microwave oven with a heater as a heating source in addition to microwave to cook a variety of foods has been launched. 
       FIG. 8  is an exploded perspective view showing a major portion of a microwave oven according to a prior art. 
     As shown in the figure, a cooking chamber  711  is provided within a cavity assembly  710  of the microwave oven. In addition, a porous portion  715  is provided in a side of an upper plate  713  of the cavity assembly  710  corresponding to the ceiling of the cooking chamber  711 . The porous portion  715  is formed to have a plurality of holes bored through the upper plate  713  in the form of a generally rectangular shape. 
     In addition, an insulator  717  is installed on an upper surface of the upper plate  713 . A heater opening portion  718  is formed in a portion of the insulator  717  corresponding to the porous portion  715 . The heater opening portion  718  is a portion through which light and/or heat generated in a heater assembly  721  is supplied into the cooking chamber  711 . 
     Also, a heater base  719  is provided on a portion of the insulator  717  corresponding to an inner peripheral portion of the heater opening portion  718 . The heater base  719  is a portion to which the heater assembly  721  is fixed. The heater base  719  is shaped in a rectangular frame, and extension ribs  19 R(=&gt; 719 R) extending downward are provided on an inner peripheral portion of the heater base  719 . 
     The heater base  719  is equipped with the heater assembly  721 . The heater assembly  721  serves to heat food in the cooking chamber  711  by generating light and/or heat by applying power to the heater assembly  721 . The heater assembly  721  is provided with a pair of heaters H 7  and H 7 ′ for substantially generating light and/or heat. The heaters H 7  and H 7 ′ may consist of, for example, a halogen heater and a ceramic heater. 
     The heaters H 7  and H 7 ′ are respectively fixed to an upper surface of a heater supporter  723 . The heater supporter  723 , which is shaped in a rectangular frame, is fixed to the heater base  719  with the heaters H 7  and H 7 ′ fixed to the upper surface of the heater supporter  723 . 
     A reflecting plate  725  is provided above the heaters H 7  and H 7 ′. The reflecting plate  725  serves to reflect the light and/or heat of the heaters H 7  and H 7 ′ toward the interior of the cooking chamber  711 . The reflecting plate  725  is provided with a plurality of vents  725 H. The vents  725 H allow a portion of airflow generated from a cooling fan assembly (not shown) to be introduced through the vents to cool the heaters H 7  and H 7 ′. 
     In addition, a pair of shield covers  727  and  729  are provided above the reflecting plate  725 . The shield covers  727  and  729  serve to prevent that microwave generated in electric parts and applied into the cooking chamber  711  leaks to the outside through the porous portion  715 . Unexplained reference numeral S 7  designates a screw for fixing the heater assembly  721  to the heater base  719 . 
     However, the microwave oven according to the above prior art has the following problems. 
     In the prior art, there are provided a plurality of the shield covers  727  and  729  in order to prevent microwave applied into the cooking chamber  711  from leaking to the outside through the porous portion  715 . However, there is a disadvantage in that only the shield covers  727  and  729  cannot sufficiently prevent the microwave from leaking through the porous portion  715 . 
     DISCLOSURE 
     Technical Problem 
     The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a device for preventing microwave leakage for a microwave oven, which is configured to prevent microwave supplied into a cooking chamber from leaking. 
     Another object of the present invention is to provide a device for preventing microwave leakage for a microwave oven, which is configured to prevent microwave from leaking with a simple configuration. 
     Technical Solution 
     According to an aspect of the present invention for achieving the objects, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly formed with an opening portion through which heating energy generated in an energy generating means is supplied into a cooking chamber provided within the cavity assembly; a cover provided on a side of the cavity assembly to cover the opening portion; and a choke member provided between the cavity assembly and the cover to prevent microwave supplied into the cooking chamber from leaking through a gap between the cavity assembly and the cover. 
     According to another aspect of the present invention, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly provided with a cooking chamber therein and formed with an opening portion through which heating energy is supplied into the cooking chamber; an energy generating means installed on an upper portion of the opening portion and generating the heating energy supplied into the cooking chamber through the opening portion; and a choke member provided between a face of the cavity assembly and the energy generating means, the choke member preventing microwave applied into the cooking chamber from leaking to an outside through a gap between the cavity assembly and the energy generating means. 
     According to a further aspect of the present invention, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly provided with a cooking chamber therein and formed with a porous portion on an upper surface of the cavity assembly; an insulator installed on the upper surface of the cavity assembly and provided with an opening portion corresponding to the porous portion; an energy generating means installed on an upper portion of the opening portion and generating heating energy supplied into the cooking chamber through the opening portion and the porous portion; and a choke member provided between the insulator and the energy generating means, the choke member preventing microwave applied into the cooking chamber from leaking to an outside through a gap between the cavity assembly and the energy generating means. 
     Preferably, the energy generating means is a heater assembly including at least a heater for supplying light or heat supplied into the cooking chamber. 
     More preferably, the choke member is formed with a blank portion corresponding to the opening portion, and an inner peripheral portion of the blank portion is provided with a choke portion formed for a plurality of choke pieces and indented portions to be sequentially alternated at predetermined intervals. 
     According to a still further aspect of the present invention, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly provided with a cooking chamber therein, formed with a heater opening portion in a surface of the cavity assembly, and provided with a choke portion on an inner peripheral portion of the heater opening portion to prevent microwave supplied into the cooking chamber from leaking; and a heater assembly installed on an upper portion of the heater opening portion and generating heating energy supplied into the cooking chamber. 
     According to a still further aspect of the present invention, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly provided with a cooking chamber therein and formed with a porous portion on a surface of the cavity assembly; an insulator installed on the surface of the cavity assembly in which the porous portion is formed, formed with a heater opening portion corresponding to the porous portion, and provided with a choke portion on an inner peripheral portion of the heater opening portion to prevent microwave supplied into the cooking chamber from leaking; and a heater assembly installed on an upper portion of the heater opening portion and generating heating energy supplied into the cooking chamber. 
     Preferably, the inner peripheral portion of the heater opening portion is further provided with a heater base shaped in a rectangular frame to which the heater assembly is fixed, and the choke portion is installed to an inner peripheral portion of the heater base. 
     According to a still further aspect of the present invention, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly provided with a cooking chamber therein and formed with a heater opening portion on a surface of the cavity assembly, the heater opening portion communicating with the cooking chamber; and a heater assembly installed on an upper portion of the heater opening portion, generating heating energy supplied into the cooking chamber, and provided with a choke portion for preventing microwave supplied into the cooking chamber from leaking through a gap between the cavity assembly and the heater assembly. 
     Preferably, the heater assembly comprises at least a heater for generating light or heat, a heater supporter fixed to a surface of the cavity assembly with the heater fixed to the heater supporter, and a reflecting plate for reflecting the light or heat of the heater into the cooking chamber, and the choke portion is formed integrally with the heater supporter or the reflecting plate. 
     More preferably, the heater assembly comprises at least a heater for generating light or heat, a heater supporter fixed to a surface of the cavity assembly with the heater fixed to the heater supporter, a reflecting plate for reflecting the light or heat of the heater into the cooking chamber, and a covering member for covering the heater opening portion in addition to the heater, the heater supporter and the reflecting plate, and the choke portion is formed integrally with the covering member. 
     According to a still further aspect of the present invention, there is provided a device for preventing microwave leakage for a microwave oven, comprising a cavity assembly with a cooking chamber in which food is heated provided therein; a heater assembly formed on a side of the cavity assembly to supply light or heat for heating food into the cooking chamber through an opening portion communicating with the cooking chamber; and a leakage preventing means for preventing microwave from leaking through a gap between the cavity assembly and the heater assembly. 
     Preferably, the leakage preventing means is a choke member provided between the cavity assembly and the heater assembly and comprising a choke portion for preventing the microwave leakage which is formed for a plurality of choke pieces and indented portions to be sequentially alternated at predetermined intervals. 
     More preferably, the leakage preventing means is a choke portion installed to a heater base to which the heater assembly is fixed, the choke portion being formed for a plurality of choke pieces and indented portions to be sequentially alternated at predetermined intervals. 
     Still more preferably, the heater base is fixed to an insulator provided on a surface of the cavity assembly. 
     Still more preferably, the leakage preventing means is a choke portion installed to the heater assembly and formed for a plurality of choke pieces and indented portions to be sequentially alternated at predetermined intervals. 
     Still more preferably, the heater assembly comprises at least a heater for generating light or heat, a heater supporter fixed to a surface of the cavity assembly with the heater fixed to the heater supporter, a reflecting plate for reflecting the light or heat of the heater into the cooking chamber, and a covering member for covering the heater opening portion in addition to the heater, the heater supporter and the reflecting plate, and the choke portion is installed to any one of the heater supporter, the reflecting plate and the covering member and formed for a plurality of choke pieces and indented portions to be sequentially alternated at predetermined intervals. 
     Advantageous Effects 
     According to a device for preventing microwave leakage for a microwave oven of the present invention, the following advantages can be expected. 
     According to the present invention, in order to prevent microwave supplied into a cooking chamber from leaking through a gap between a cavity assembly and a heater assembly, a choke member with a choke portion is provided between the cavity assembly and the heater assembly. Therefore, it is possible to more ensure the stability of a microwave oven using microwave as a primary heating source, thereby increasing the reliability of the manufactures. 
     Further, in the present invention, the choke portion is not provided in the separate choke member, but may be formed integrally with any one of components of the cavity assembly or heater assembly. Therefore, with a simpler configuration, it is possible to prevent microwave from leaking to the outside of the cooking chamber and at the same time to reduce the man-hour needed for the works and the production costs for the manufactures. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view showing a major portion of a microwave oven having a first embodiment of a device for preventing microwave leakage according to the present invention; 
         FIG. 2  is a perspective view showing a choke member of the first embodiment according to the present invention; 
         FIG. 3  is an exploded perspective view showing a major portion of a microwave oven having a second embodiment of a device for preventing microwave leakage according to the present invention; 
         FIG. 4  is an exploded perspective view showing a major portion of a microwave oven having a third embodiment of a device for preventing microwave leakage according to the present invention; 
         FIG. 5  is an exploded perspective view showing a major portion of a microwave oven having a fourth embodiment of a device for preventing microwave leakage according to the present invention; 
         FIG. 6  is an exploded perspective view showing a major portion of a microwave oven having a fifth embodiment of a device for preventing microwave leakage according to the present invention; 
         FIG. 7  is an exploded perspective view showing a major portion of a microwave oven having a sixth embodiment of a device for preventing microwave leakage according to the present invention; and 
         FIG. 8  is an exploded perspective view showing a major portion of a microwave oven according to a prior art. 
     
    
    
     BEST MODEL 
     Hereinafter, a preferred embodiment of a device for preventing microwave leakage for a microwave oven according to the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is an exploded perspective view showing a major portion of a microwave oven having a first embodiment of a device for preventing microwave leakage according to the present invention, and  FIG. 2  is a perspective view showing a choke member of the first embodiment according to the present invention. 
     As shown in the figures, a cooking chamber  111  selectively opened and closed by a door (not shown) is provided within a cavity assembly  110  of a microwave oven. A porous portion  115  is also provided in an upper plate  113  of the cavity assembly  110  to have a plurality of holes bored through the upper plate  113  in the form of a generally rectangular shape. 
     The porous portion  115  allows light and/or heat of a heater assembly  121 , which will be described below, to be supplied into the cooking chamber  111  through the porous portion  115 . At this time, in consideration of a wavelength and the like of microwave supplied into the cooking chamber  111 , the respective holes of the porous portion  115  are designed to have a diameter to prevent microwave from leaking to the outside. 
     An insulator  117  is installed to the upper plate  113  of the cavity assembly  110 . A heater opening portion  118  is formed in a portion of the insulator  117 , i.e., a portion corresponding to the porous portion  115 . The heater opening portion  118  is a portion through which light and/or heat generated in a heater assembly  121  is supplied into the cooking chamber  111 . The heater opening portion  118  is formed in a rectangular shape corresponding to the porous portion  115 . 
     In addition, a heater base  119  is provided on a portion of the upper plate  113  corresponding to the heater opening portion  118 . The heater base  119  is to install the heater assembly  121 . The heater base  119  is shaped in a rectangular frame. Also, extension ribs  119 R extending downward by a predetermined length are provided on an inner peripheral portion of the heater base  119 . 
     The heater base  119  is equipped with the heater assembly  121 . The heater assembly  121  generates a predetermined energy as a heating source in addition to microwave. For example, the heater assembly  121  is provided with a heater, a lamp or the like for generating light and/or heat by applying power thereto, and the light and/or heat acts as a heating source for heating food loaded in the cooking chamber  111 . In the present invention, the heater assembly  121  is used to intend to include all means for generating energy capable of heating food except microwave. 
     The heater assembly  121  is provided with heaters H 1  and H 1 ′ for generating light and/or heat by applying power thereto. In the present invention, as the heater H 1  or H 1 ′, any type of heater such as a halogen lamp or a ceramic heater may be used if it generates light or heat by applying power thereto. The heaters H 1  and H 1 ′ are fixed to an upper surface of a heater supporter  123  shaped in a rectangular frame. The heater supporter  123  is installed to an upper surface of the insulator  117  adjacent to the heater opening portion  118 , with the heaters H 1  and H 1 ′ fixed to the upper surface of the heater supporter  123 . 
     A reflecting plate  125  is provided above the heaters H 1  and H 1 ′. The reflecting plate  125 , which is installed so as to enclose the heaters H 1  and H 1 ′ from their top, serves to reflect light and/or heat generated in the heaters H 1  and H 1 ′ into the cooking chamber  111  through the heater opening portion  118  and the porous portion  115 . In addition, the reflecting plate  125  is formed with a plurality of vents  125 H for cooling the heaters H 1  and H 1 ′. 
     The porous portion  115  simultaneously performs the function of allowing the light and heat generated in the heater to pass into the cooking chamber  111  and the function of preventing the microwave supplied into the cooking chamber from leaking to the outside. That is, by designing the circular holes of the porous portion  115  to be proper in size, the microwave having a predetermined wavelength is prevented from leaking. Such a configuration itself of the porous portion is applied to a door or the like of a microwave oven. Also, the microwave leaking from the porous portion  115  is more securely blocked by a choke member  131  of the present invention as described below. 
     In addition, a pair of shield covers  127  and  129  are installed above the reflecting plate  125 . The shield covers  127  and  129  prevent leakage of microwave applied into the cooking chamber  111  through the porous portion  115  and the heater opening portion  118 . 
     In the meantime, the choke member  131  is provided between the insulator  117  and the heater assembly  121 . The choke member  131  is installed on the heater base  119  of the insulator  117 , and thus prevents microwave applied into the cooking chamber  111  from leaking to the outside through a gap between the heater assembly  121  and the heater base  119 , i.e., the heater opening portion  118 . 
     As shown in  FIG. 2  in detail, the choke member  131  is formed in a rectangular shape for covering the heater opening portion  118 . A blank portion  133  is formed in the choke member  131 . The blank portion  133  allows light and/or heat generated in the heaters H 1  and H 1 ′ to be supplied into the cooking chamber  111 . 
     The blank portion  133  is formed in a shape and size corresponding to the heater opening portion  118 . Also, a choke portion  135  is provided on an inner peripheral portion of the blank portion  133 . The choke portion  135  extends downward from the inner peripheral portion of the blank portion  133 . When the choke member  131  is coupled to the heater base  119 , the choke portion  135  is inserted into the opening portion  118  of the heater base  119  and positioned adjacent to the extension ribs  119 R. 
     The choke portion  135  is formed to comprise rectangle-shaped protruding portions (choke pieces) and indented portions which are sequentially alternated at predetermined intervals on the inner peripheral portion of the blank portion  133 . The prevention of the microwave leakage by the choke portion  135  has already been known, and thus the detailed descriptions thereof will be omitted. 
     The size of the choke pieces applied to the door and the interval therebetween are determined depending on a wavelength of microwave and a size of the opened portions. In general, the choke pieces are designed so that a width of the choke piece is about 12.0 mm and an interval between the choke pieces is 7.0 to 8.0 mm. The longer the choke piece, the more effective the prevention of the microwave leakage. However, the choke piece is generally designed to be 6.5 mm or so. 
     Therefore, in the present embodiment, in consideration of the shape and size of the heater opening portion  118 , the choke portion  135  will be designed. Also, it is natural that the microwave leakage can be substantially prevented by the shape, size and the like of the choke pieces and indented portions of the choke portion  135 . However, since the extension ribs  119 R are provided on the inner peripheral portion of the heater base  119  to extend downward, the choke portion  135  will be designed to be longer than the extension ribs  119 R. 
     Also, in the present embodiment, the choke member  133  is provided between the heater base  119  and the heater assembly  121  so that the choke portion  135  is directed downward. However, the choke member  133  may be installed so that the choke portion  135  is directed upward by rotating 180 degrees from a state shown in  FIGS. 1 and 2 . 
     Hereinafter, the operation of the first embodiment of the device for preventing the microwave leakage for a microwave oven according to the present invention so configured will be described in detail. 
     First, the insulator  117  in which the heater base  119  is previously installed is mounted to the upper plate  113  of the cavity assembly  110 . At this time, during the installation of the insulator  117 , the porous portion  115  of the upper plate  113  and the heater opening portion  118  of the insulator  117  are positioned corresponding to each other. 
     In such a state, the choke member  131  is fixed to the insulator  117 , substantially to the heater base  119 . At this time, the choke member  131  is fixed to the insulator  117  so that the choke portion  135  of the choke member  131  is positioned in the region of the porous portion  115  and the heater opening portion  118 . 
     Then, the heater supporter  123  to which the heaters H 1  and H 1 ′ and the reflecting plate  125  are previously assembled is positioned on the heater base  119  on the portion corresponding to the heater opening portion  118 . Then, the shield covers  127  and  129 , the reflecting plate  125 , the choke member  131 , the insulator  117 , and the upper plate  113  of the cavity assembly  110  are fastened to each other using screws S 1 , thereby completing the assembly. 
     In the meantime, when completing the assembly, the choke portion  135  capable of preventing the microwave leakage is provided on the inside surface of the heater opening portion  118 . Thus, during a process of cooking food in the cooking chamber  111  using microwave, it is possible for the choke portion  135  of the choke member  131  to securely prevent microwave from leaking through a gap between the heater opening portion  118  and the heater assembly  121 . 
     MODE FOR INVENTION 
     Hereinafter, a second embodiment of a device for preventing microwave leakage according to the present invention will be described in detail with reference to the accompanying drawing. 
       FIG. 3  is an exploded perspective view showing a major portion of a microwave oven having the second embodiment of the device for preventing microwave leakage according to the present invention. 
     As shown in the figure, an upper plate  213  of a cavity assembly  210  which is provided with a cooking chamber  211  for cooking food is formed with a heater opening portion  215 . In addition, a portion of the upper plate  213  corresponding to an inner peripheral portion of the heater opening portion  215  is provided with a heater base  219 . 
     The heater base  219  is equipped with a heater assembly  211 (=&gt; 221 ). In the present embodiment, the configuration of the heater assembly  211 (=&gt; 221 ), i.e., heaters H 2  and H 2 ′, a heater supporter  223 , a reflecting plate  225 , and shield covers  227  and  229 , is identical to that of the aforementioned first embodiment. The heater assembly  211 (=&gt; 221 ) is fixed with screws S 2 . 
     In the meantime, a choke member  231  is provided between the upper plate  213  and the heater assembly  211 , substantially between the heater base  219  and the heater assembly  211 . The choke member  231 , which is identical to that of the first embodiment, serves to prevent leakage of the microwave applied to the cooking chamber  211 . That is, the choke member  231  is formed with a blank portion  233  corresponding to the opening portion  215 . In addition, a choke portion  235  extends downward from an inner peripheral portion of the blank portion  233 . 
     That is, as compared with the aforementioned first embodiment, a porous portion and an insulator are omitted in the present embodiment. Thus, the heater base  219  is fixed to the upper plate  213  contrary to the first embodiment in which the heater base is provided in the insulator, and the heater opening portion  215  is formed in the upper plate  213  contrary to the first embodiment in which the heater opening portion is formed in the insulator. Further, the choke member  231  is provided between the heater assembly  211  and the heater base  219  provided in the upper plate  213 . 
     Next, a third embodiment of a device for preventing microwave leakage according to the present invention will be described in detail with reference to the accompanying drawing. 
       FIG. 4  is an exploded perspective view showing a major portion of a microwave oven having the third embodiment of the device for preventing microwave leakage according to the present invention. 
     As shown in the figure, a cooking chamber  311  selectively opened and closed by a door (not shown) is provided within a cavity assembly  310  of the microwave oven. Also, an upper plate  313  of the cavity assembly  310  is formed with a porous portion  315  in which a plurality of holes are formed. The porous portion  315  allows light and/or heat of a heater assembly  321 , which will be described below, to be supplied into the cooking chamber  311  through the porous portion  315 . 
     The upper plate  313  is equipped with an insulator  317 . A heater opening portion  318  is formed in a side of the insulator  317 . The heater opening portion  318  is positioned corresponding to the porous portion  315 , with the insulator  317  installed to the upper plate  313 . Thus, the light and/or heat of the heater assembly  321  is supplied into the cooking chamber  311  through the porous portion  315  and the heater opening portion  318 . 
     A heater base  319  is installed to a portion of the insulator  317  corresponding to an inner peripheral portion of the heater opening portion  318 . The heater base  319  is a portion to which the heater assembly  321  is substantially installed. In addition, a choke portion  320  is provided on an inner peripheral portion of the heater base  319 . The choke portion  320  is formed in the same shape as the aforementioned first embodiment, and thus, serves to prevent microwave applied into the cooking chamber  311  from leaking through a gap between the heater base  319  and the heater assembly  321 . 
     That is, in the present embodiment, the choke portion  320  is formed on not a additional member but the heater base  319 . Therefore, according to the present embodiment, contrary to the aforementioned first embodiment, there is provided no additional choke member provided with the choke portion  320 , whereby with a simpler configuration, microwave applied into the cooking chamber  311  can be prevented from leaking through the gap between the heater base  319  and the heater assembly  321 . 
     In addition, the heater base  319  is provided with the heater assembly  321 . The heater assembly  321 , which supplies light and/or heat into the cooking chamber  311  through the heater opening portion  318  and the porous portion  315 , comprises heater H 3  and H 3 ′, a heater supporter  323 , a reflecting plate  325 , and a shield cover  327   329 , which are identical to those of the aforementioned first embodiment, and of which the descriptions will thus be omitted. 
     A fourth embodiment of a device for preventing microwave leakage according to the present invention will be described in detail with reference to the accompanying drawing. 
       FIG. 5  is an exploded perspective view showing a major portion of a microwave oven having the fourth embodiment of the device for preventing microwave leakage according to the present invention. 
     As shown in the figure, a cooking chamber  411  is provided within a cavity assembly  410  of the microwave oven. In addition, a porous portion  415  is provided in a side of an upper plate  413  of the cavity assembly  410  corresponding to the ceiling of the cooking chamber  411 . Also, an insulator  417  is installed on an upper surface of the upper plate  413 , and a heater opening portion  418  is formed in a side of the insulator  417 . Further, the insulator  417  is provided with a heater base  419  which is provided with extension ribs  419 R extending downward from an inner peripheral portion of the heater base  419 . 
     The heater base  419  is equipped with a heater assembly  421 . The heater assembly  421  includes a pair of heaters H 4  and H 4 ′, a heater supporter  423 , a reflecting plate  425 , and shield covers  427  and  429 . Since such a configuration of the present embodiment is identical to that of the aforementioned first embodiment, the detailed descriptions thereof will be omitted. 
     However, in the present embodiment, a choke portion  424 , which prevents microwave applied into the cooking chamber  411  for heating food from leaking through a gap between the heater base  419  and the heater assembly  421 , is provided on a bottom surface of an edge of the heater supporter  423 . 
     That is, the choke portion  424  is formed such that rectangle-shaped choke pieces extending downward from an inner peripheral portion of the heater supporter  424  and indented portions are sequentially alternated at predetermined intervals. Therefore, the choke portion  424  is positioned within the heater opening portion  418 . The shape and size of the choke portion  424  will be determined to more effectively prevent microwave leakage depending on the shape and size of the heater opening portion  418 . 
     In other words, in the present embodiment, since the choke portion  424  is formed integrally with the heater supporter  423 , there is no need for an additional member in which the choke portion is provided as in the aforementioned third embodiment. Thus, with a simpler configuration, microwave applied into the cooking chamber  411  can be prevented from leaking. 
     A fifth embodiment of a device for preventing microwave leakage for a microwave oven according to the present invention will be described in detail with reference to the accompanying drawing. 
       FIG. 6  is an exploded perspective view showing a major portion of a microwave oven having the fifth embodiment of the device for preventing microwave leakage according to the present invention; 
     As shown in the figure, in the present embodiment, a cooking chamber  511  is provided within a cavity assembly  510 , and a porous portion  515  is provided in a side of an upper plate  513  of the cavity assembly  510 . Also, an insulator  517  formed with a heater opening portion  518  is installed on an upper surface of the upper plate  513 . In addition, the insulator  517  is provided with a heater base  519  for fixing a heater assembly  521 . 
     In the meantime, the heater assembly  521  comprises a pair of heaters H 5  and H 5 ′, a heater supporter  523 , a reflecting plate  525 , and shield covers  527  and  529 . In the present embodiment, the heater supporter  523  is generally formed in an “I” shape. It is for the purpose of allowing a choke portion  528 , which will be described below, to pass through the heater supporter  523  and to be positioned within the heater opening portion  518 . Therefore, the heater supporter  523  may be shaped in a rectangular frame as in a prior art, and a slot for allowing the choke portion  528  to passes therethrough may be formed in the reflecting plate  525 . 
     Further, in the present embodiment, the shield cover  527  which is positioned relatively lower among the shield covers  527  and  529  is provided with the choke portion  528 . The choke portion  528  serves to prevent the microwave applied into the cooking chamber  511  for heating food from leaking to the outside through a gap between the heater base  519  and the heater assembly  521 . The choke portion  528  extends downward from a bottom surface of an edge of the shield cover  527 , passes through both sides of the heater supporter  523 , and is positioned within the heater opening portion  518 . 
     That is, in the present embodiment, the choke portion  528  is formed integrally with the shield cover  527 . Thus, as in the aforementioned third and fourth embodiments, with a simpler configuration, the microwave applied into the cooking chamber  511  can be prevented from leaking. 
     A sixth embodiment of a device for preventing microwave leakage for a microwave oven according to the present invention will be described in detail with reference to the accompanying drawing. 
       FIG. 7  is an exploded perspective view showing a major portion of a microwave oven having the sixth embodiment of the device for preventing microwave leakage according to the present invention. 
     As shown in the figure, a cooking chamber  611  is provided within a cavity assembly  610  of the microwave oven. The cooking chamber  611 , in which food is heated, is selectively opened and closed by a door (not shown). In addition, an upper plate  613  of the cavity assembly  610  is formed with a heater opening portion  615 . The heater opening portion  615  is formed by having a portion of the upper plate  613  to be cut in a rectangular shape. 
     In the present embodiment, a choke portion  616  is provided on an inner peripheral portion of the heater opening portion  615 . The choke portion  616  serves to prevent microwave applied into the cooking chamber  611  from leaking to the outside through a gap between the heater opening portion  615  and a heater assembly  621  that will be described below. The choke portion  616  may be substantially formed integrally with the upper plate  613 . That is, in a process of cutting a portion of the upper plate  613  in order to form the heater opening portion  615 , portions of the upper plate  613  corresponding to an inner peripheral portion of the heater opening portion  615  are cut so that rectangle-shaped choke pieces and indented portions are alternated, and the choke pieces are then bent downward to be perpendicular to the upper plate  613 , whereby the choke portion  616  is formed. 
     In the meantime, the upper plate  613  is provided with the heater assembly  621 . The heater assembly  621  substantially supplies light and/or heat for heating food into the cooking chamber  611 . Here, the configuration of the heater assembly  621  comprising heaters H 6  and H 6 ′, a heater supporter  623 , a reflecting plate  625 , and shield covers  627  and  629  is identical to that of the aforementioned first embodiment, so that the detailed descriptions thereof will be omitted. 
     As in the aforementioned third to fifth embodiments, an additional member provided with the choke portion may also be omitted in the present embodiment. That is, according to the present embodiment, the choke portion  616  is formed integrally with the upper plate  613 , whereby it is possible to simply prevent the microwave leakage. 
     The scope of the present invention is not limited to the embodiments described above but is defined by the claims. It will be apparent that those skilled in the art can make various modifications and changes thereto within the scope of the invention defined by the claims.