Abstract:
A microwave oven having a magnetron that generates microwaves, a magnetron driving circuit that supplies high voltage power to the magnetron and a machine room that accommodates the magnetron and the magnetron driving circuit. The microwave oven includes a single magnetron driving circuit board in which the magnetron and the electronic devices of the magnetron driving circuit are mounted thereon. The single magnetron driving circuit board is fixedly attached to the machine room by mounting members.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of Korean Application No. 2002-55990, filed on Sep. 14, 2002, 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 microwave ovens, and more particularly, to a magnetron driving circuit board for a microwave oven, in which a magnetron and a magnetron driving circuit are mounted on a single board. 
   2. Description of the Related Art 
   In general, a circuit for driving a magnetron in a microwave oven comprises high voltage devices including a high voltage condenser, a high voltage diode, a high voltage transformer, etc. The magnetron driving circuit boosts a commercial alternating current AC voltage to a voltage of 2000 V using the high voltage transformer, boosts the voltage of 2000 V to a voltage of 4000 V required to drive the magnetron, and supplies the voltage of 4000 V to the magnetron. 
     FIG. 1  is a partially cutaway view showing a construction of a machine room of a conventional microwave oven. As depicted in  FIG. 1 , an oven body  120  is provided with a cooking cavity  121 , and a machine room  122  in which a variety of electric and electronic devices are installed. A door  123  is attached to a front of the cooking cavity  121  to selectively open and close the cooking cavity  121 , while a control panel  124  is attached to a front of the machine room  122  to control various operations of the conventional microwave oven. A circuit board  135  is positioned in back of the control panel  124  to control an entire operation of the microwave conventional oven in response to a manipulation of the control panel  124 . 
   High voltage devices including a magnetron  130 , a high voltage transformer  131 , a high voltage condenser  182 , a high voltage diode  184 , etc., are installed in the machine room  122 . The magnetron  130  receives high voltage power from the high voltage devices  131 ,  182  and  184 , and generates microwaves to irradiate the cooking cavity  121 . As a result, food is cooked in the cooking cavity  121  by the microwaves irradiated by the magnetron  130 . 
   Other electric and electronic devices except for the above-described electric and electronic devices, which are required to implement various operations of the microwave oven, are disposed in the machine room  122 . A blowing fan  132  is mounted on a back of the machine room  122  to suck outside air and cool the magnetron  130  with the sucked outside air. A noise filter  133  is installed at a position above the blowing fan  132  to eliminate high voltage noise. A power cord  134  is connected to the noise filter  133  to receive power from an outside power source (not shown). 
   Power and control signals are supplied to the various electric and electronic devices positioned in the machine room  122  through two bundles of wires  140  and  150 . The two bundles of wires  140  and  150  are a first bundle of wires  140  and a second bundle of wires  150  that supply the power and control signals to electric and electronic devices positioned on a rear and front portions of the machine room  122 , respectively. The first and second bundles of wires  140  and  150  are electrically connected to each other through two terminals  142  and  152 . 
     FIG. 2  is a circuit diagram of the conventional microwave oven, which shows electrical connections between the magnetron  130 , the high voltage transformer  131 , the high voltage condenser  182 , the high voltage diode  184 , and the noise filter  133 . 
   A construction of the machine room  122  of the conventional microwave oven is described below. The magnetron  130  and the high voltage devices  131 ,  182  and  184  are mounted on a wall and a bottom of the machine room  122 , respectively. The first and second bundles of wires  140  and  150  are intertwined to connect the magnetron  130  and the high voltage devices  131 ,  182  and  184  to corresponding locations. 
   Due to a complicated configuration of the machine room of a conventional microwave oven, an assembly of the machine room requires excessive time in a process of manufacturing the conventional microwave oven. Further, the complicated configuration of the machine room causes utilization of the machine room to be deteriorated, which is a cause of increasing a size of an oven body. 
   SUMMARY OF THE INVENTION 
   Accordingly, an aspect of the present invention is to provide a microwave oven in which a magnetron and other high voltage devices are mounted on a single board to be packaged, so an assembly of a machine room is simplified, and utilization of the machine room is increased or a size of an oven body is reduced. 
   Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
   The foregoing and/or other aspects are achieved by providing a microwave oven having a magnetron that generates microwaves, a magnetron driving circuit that supplies high voltage power to the magnetron and a machine room that accommodates the magnetron and the magnetron driving circuit, which includes a magnetron driving circuit board in which the magnetron and the electronic devices of the magnetron driving circuit are mounted on a single board, wherein the magnetron driving circuit board is fixedly attached to the machine room by mounting units. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other aspects and advantages of the present invention will become apparent and more appreciated from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
       FIG. 1  is a partially cutaway view showing a construction of a machine room of a conventional microwave oven; 
       FIG. 2  is a circuit diagram of the conventional microwave oven; 
       FIGS. 3A and 3B  are views of a magnetron driving circuit board in accordance with a first embodiment of the present invention; 
       FIG. 4  is a diagram showing a wiring of the magnetron driving circuit board of  FIG. 3A ; 
       FIG. 5  is a partially exploded perspective view showing an attachment of the magnetron driving circuit board of  FIG. 4  to a machine room; and 
       FIGS. 6A and 6B  are views of a magnetron driving circuit board in accordance with a second embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. 
   A microwave oven in accordance with a first embodiment of the present invention is described with reference to  FIGS. 3A  to  5 .  FIGS. 3A and 3B  are views of a magnetron driving circuit board  300  in accordance with the first embodiment of the present invention. As depicted in  FIG. 3A , a magnetron  304  and an air cover  306  are fixedly mounted on an upper portion of a circuit board  302 . A high voltage condenser  318 , a high voltage diode  310  and a high voltage transformer  308  are fixedly mounted on a lower portion of the circuit board  302  below the magnetron  304  and the air cover  306 . The air cover  304  operates to supply air generated by a blowing fan (now shown) to an interior of a cooking cavity (not shown). The circuit board  302  is provided with a power cable  314  that supplies power and a control signal cable  312  that receives control signals from a control unit (not shown). The power cable  314  and the control signal cable  312  are, respectively, constructed in a form of a harness to be easily connected to a power terminal and control terminals, respectively. A plurality of mounting holes  316  is formed along edges of the circuit board  302  to receive mounting units. 
     FIG. 3B  is a view showing a back of the magnetron driving circuit board  300 . As depicted in  FIG. 3B , an antenna  322  of the magnetron  304  protrudes from the back of the magnetron driving circuit board  300 , and microwaves irradiate through the antenna  322 . An air inlet  320  is formed in the circuit board  302  to supply air supplied through the air cover  306 , as shown in  FIG. 3A , to an interior of the cooking cavity. A waveguide (not shown) and an air inlet as shown in  FIG. 5 , must be formed in a partition wall  508 , situated between the machine room  506 , and the cooking cavity of the body of the microwave oven employing the magnetron driving circuit board  300  to correspond to positions of the antenna  322  and the air inlet  320 . Accordingly, a layout and specifications of the above-described parts may be designed at a stage of developing a product. 
     FIG. 4  is a diagram showing a wiring of the magnetron driving circuit board  300  of FIG.  3 A. As depicted in  FIG. 4 , wiring is set up between the magnetron  304 , the high voltage condenser  318 , the high voltage diode  310  and the high voltage transformer  308 , so that an alternating current AC voltage is converted into a direct current DC voltage by a rectification of the high voltage diode  310  and a smoothing by the high voltage condenser, the converted direct current DC voltage is boosted to a certain voltage and the boosted voltage is supplied to the magnetron  304 . The wiring may be implemented by general coated copper wires or in a patterning manner that is generally used in printed circuit boards. 
     FIG. 5  is a partially exploded perspective view showing an attachment of the magnetron driving circuit board  300  to the machine room  506 . As depicted in  FIG. 5 , when the magnetron driving circuit board  300  is fixedly mounted on the partition wall  508  of the machine room  506 , the magnetron  304  and the air cover  306  are arranged to face an antenna receiving hole  502  and an air inlet  504 , respectively. By mounting the magnetron driving circuit board  300  on the partition wall  508  of the machine room  506  using mounting members  510 , the mounting of the magnetron  304  and the high voltage devices  308 ,  310  and  318  used to drive the magnetron  304  can be simply achieved. 
     FIGS. 6A and 6B  are views of a magnetron driving circuit board in accordance with a second embodiment of the present invention, which shows a case where an air cover does not exist and a magnetron  604  and high voltage devices, such as the high voltage transformer  608 , the high voltage diode  610  and the high voltage condenser  618 , are mounted on a board  602 . 
   As depicted in  FIGS. 6A and 6B , in a magnetron driving circuit board  600 , the magnetron  604  is attached to the board  602  with a part of the magnetron  604  protruding from a front surface of the board  602 . A plurality of mounting holes  650  is formed in the board  602 . The magnetron  604  is secured to the board  602  by tightening mounting members into the mounting holes  650 . A plurality of mounting holes  616  is formed on a back of the magnetron  604  so that the magnetron  604  is fixedly mounted on the partition wall separating the machine room and the cooking cavity of the oven body of the microwave oven by tightening mounting members into the plurality of mounting holes  616 . The high voltage diode  610 , a power cable  614 , a control signal cable  612  and the high voltage condenser  618  are mounted on the front surface of the board  602 , while the high voltage transformer  608  is mounted on a back surface of the board  602 . 
     FIG. 6B  is a view showing the back of the magnetron driving circuit board  600  of FIG.  6 A. As depicted in  FIG. 6B , the antenna  622  of the magnetron  604  protrudes from the back surface of the board  602 , so microwaves irradiate from the antenna  622 . Since the magnetron driving circuit board  600  is not provided with an air cover, a position of an installation of the magnetron driving circuit board  600  has to be determined in consideration of a position of a waveguide that is disposed between the machine room and the cooking cavity of the oven body of the microwave oven. Accordingly, a layout and specifications of the above-described parts may be designed at the stage of developing a product. 
   As is apparent from the above description, a microwave oven is provided in which a magnetron and other high voltage devices are mounted on a single circuit board to be packaged, so that an assembly of a machine room can be simplified, and utilization of the machine room can be increased or a size of an oven body can be reduced. 
   Although a few preferred embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.