Abstract:
A cooking apparatus equipped with heaters and a method of controlling the same. An aspect of the present invention is to increase convenience of a user by identifying a kind of an accessory, such as a wire rack, a crumb tray or the like, present in a cooking cavity based on a variation in an inner temperature of a cooking cavity at an initial operating stage of a cooking mode using the heaters and automatically performing the ON/OFF control mode of the heaters suitable for a corresponding accessory. A cooking apparatus is provided including two or more heaters installed in a first position of a cooking cavity heating food, the crumb tray is inserted in a second position of the cooking cavity and is used to contain the food in cooking modes using the heaters, and a temperature detection unit is installed between the first and second positions to detect an inside temperature of the cooking cavity. When a temperature variation rate of the cooking cavity detected by the temperature detection unit is greater than a preset value, the crumb tray is determined to be used as a cooking accessory, so an ON/OFF state of the heaters is controlled to be suitable for the cooking mode using the crumb tray.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims the benefit of Korean Application No. 2002-52598, filed Sep. 2, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to a cooking apparatus equipped with heaters and a method of controlling the same, and more particularly, to a cooking apparatus equipped with heaters and a method of controlling the same, which carries out baking and broiling or grilling.  
           [0004]    2. Description of the Related Art  
           [0005]    In general, an electric oven or a gas oven is used to bake bread, cookies or the like, or to broil or grill meat, fish or the like. In contrast, a general microwave oven heats food using electromagnetic waves generated by a magnetron. When a heater is additionally installed in the general microwave oven, various kinds of cooking, such as baking, broiling or grilling can be performed using the general microwave oven.  
         SUMMARY OF THE INVENTION  
         [0006]    Accordingly, it is an aspect of the present invention to provide a cooking apparatus equipped with heaters and method of controlling the cooking apparatus equipped with heaters, which increases convenience to a user by identifying a kind of an accessory, such as a wire rack, a crumb tray or the like, present in a cooking cavity based on a variation in an inner temperature of a cooking cavity at an initial operating stage of a cooking mode using heaters and automatically performing a ON/OFF control mode of the heaters suitable for a corresponding accessory.  
           [0007]    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.  
           [0008]    The above and other aspects are achieved by providing a cooking apparatus including two or more heater installed in a first position of a cooking cavity to heat food, a crumb tray inserted in a second position of the cooking cavity and used to contain the food during cooking modes using the heaters, and a temperature detection unit installed between the first and second positions to detect an inside temperature of the cooking cavity. When a temperature variation rate of the cooking cavity detected by the temperature detection unit is greater than a preset value, the crumb tray is determined to be used as a cooking accessory, so an ON/OFF state of the heaters is controlled to be suitable for the cooking mode using the crumb tray. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    These and other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:  
         [0010]    [0010]FIG. 1 is a partially sectional view of a related microwave oven equipped with heaters;  
         [0011]    [0011]FIG. 2 is a view of a wire rack and a crumb tray of FIG. 1;  
         [0012]    [0012]FIG. 3 illustrates a view of a control panel of the related microwave oven;  
         [0013]    [0013]FIG. 4 is a graph illustrating inside temperature characteristics of a cooking cavity of the related microwave oven;  
         [0014]    [0014]FIG. 5 is a block diagram illustrating a construction of a microwave oven equipped with heaters in accordance with an embodiment of the present invention;  
         [0015]    [0015]FIG. 6 illustrates the control panel of the microwave oven of FIG. 5;  
         [0016]    [0016]FIG. 7 is a sectional view illustrating a heat conduction process according to kinds of accessories in the microwave oven of FIG. 5;  
         [0017]    [0017]FIG. 8 is a graph illustrating inside a temperature characteristics of a cooking cavity of FIG. 5; and  
         [0018]    [0018]FIG. 9 is a flowchart illustrating a method of controlling the microwave oven of FIG. 5. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    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.  
         [0020]    [0020]FIG. 1 is a partially sectional view of a related microwave oven equipped with heaters. As shown in FIG. 1, the microwave oven is provided with a machine chamber  102  and a cooking cavity  108 . The machine chamber  102  is provided with a magnetron  104 , and electromagnetic waves (i.e., microwaves) are generated by the magnetron  104 . The magnetron  104  is supplied with high voltage power through a power source unit  106 .  
         [0021]    A glass tray  110  is mounted on a bottom of the cooking cavity  108  to be rotated by a motor  112 . The glass tray  110  is used to cook the food using microwaves generated by the magnetron  104 . An upper heater  124  and two lower heaters  126  and  128  are installed in the cooking cavity  108 . The upper heater  124  is fixedly mounted on a ceiling of the cooking cavity  108  to heat the food. The two lower heaters  126  and  128  are respectively mounted on two side portions of a rear wall of the cooking cavity  108  through rotating members  126   a  and  128   a  to heat the food. A crumb tray  114  used to bake bread, cookies and the like is inserted between the upper heater  124  and the two lower heaters  126  and  128 , and is placed on crumb tray supports  116   a  and  116   b . A temperature sensor  150  that detects an inside temperature of the cooking cavity  108  is installed above one of the crumb tray supports  116   a . A wire rack  120  used to broil meat, fish or the like is inserted under the two lower heaters  126  and  128 , and is placed on wire rack supports  130   a  and  130   b . The wire rack  120  and the crumb tray  114  used in the related microwave oven equipped with heaters are illustrated in FIGS. 2A and 2B, respectively.  
         [0022]    [0022]FIG. 3 illustrates a control panel of the related microwave oven equipped with heaters. As shown in FIG. 3, the control panel  300  is provided with a matrix type numeric pad  302  that has number buttons  0  to  9 , a start button  306  and a stop button  308 . A value set through the matrix type numeric pad  302  is displayed in a display unit  304 . The control panel  300  is provided with a broil selection button  310  and a bake selection button  312 , so a user can select a broiling mode or a baking mode. A Simul/Alter selection button  314  is used to allow the user to select an ON/OFF control mode of the heaters  124 ,  126  and  128 . The “Simul” performs control such that the upper heater  124  and the lower heaters  126  and  128  are simultaneously switched ON or OFF, while the “Alter” performs control such that the upper heater  124  and the two lower heaters  126  and  128  are alternately switched ON or OFF.  
         [0023]    To bake bread, cookies or the like, if the user puts the food on the crumb tray  114 , places the crumb tray  114  on the crumb tray supports  116   a  and  116   b  and pushes the bake selection button  312 , the food placed on the crumb tray  114  is heated by the upper heater  124  and the lower heaters  126  and  128 . In contrast, to broil meat, fish or the like, if the user puts the food on the wire rack  120 , places the wire rack  120  on the wire rack supports  130   a  and  130   b  and pushes the broil selection button  310 , the food placed on the wire rack  120  is heated by the upper heater  124  and the two lower heaters  126  and  128 . If a cooking mode such as a baking mode or a broiling mode is initiated, the upper heater  124  and the two lower heaters  126  and  128  are all operated, so food is heated. If the inside temperature of the cooking cavity  108  rises and reaches a preset temperature, the upper heater  124  and the lower heaters  126  and  128  are controlled by the ON/OFF control mode, so the inside temperature of the cooking cavity  108  is maintained at the preset temperature.  
         [0024]    [0024]FIG. 4 is a graph illustrating inside temperature characteristics of the cooking cavity of the related microwave oven equipped with heaters. As shown in FIG. 4, if the cooking mode is initiated using the heaters, the upper heater  124  and the two lower heaters  126  and  128  are simultaneously operated, so the inside temperature of the cooking cavity  108  rapidly rises. If the inside temperature of the cooking cavity  108  reaches a certain temperature, the upper heater  124  and the two lower heaters  126  and  128  are alternately operated, so the inside temperature of the cooking cavity  108  is maintained at the preset temperature.  
         [0025]    As described above, the ON/OFF control modes of the upper heater  124  and the two lower heaters  126  and  128  used in the related microwave oven include a method that controls the upper heater  124  and the two lower heaters  126  and  128  to be simultaneously switched ON or OFF and a method that controls the upper heater  124  and the two lower heaters  126  and  128  to be alternately switched ON and OFF. The ON/OFF control modes of the upper heater  124  and the two lower heaters  126  and  128  may further include a method that combines the two methods together. For the related microwave oven equipped with heaters, instructions for use of accessories, such as a wire rack and a crumb tray, and the ON/OFF control modes of the heaters used according to a kind of food, are provided through a user&#39;s manual. Accordingly, in order to desirably cook the food, the user has to know how to select an appropriate accessory and an appropriate ON/OFF control mode of the heaters according to the kind of the food.  
         [0026]    Hereinafter, a construction of a microwave oven equipped with heaters in accordance with an embodiment of the present invention with reference to FIGS.  5  to  8  is described.  
         [0027]    [0027]FIG. 5 is a block diagram illustrating a construction of the microwave oven equipped with heaters in accordance with an embodiment of the present invention. As shown in FIG. 5, a control unit  502  controls an overall operation of the microwave oven, and is connected at input terminals thereof to an input unit  504 , a temperature detection unit  522  and a storage unit  506 . The input unit  504  is provided with one or more cooking mode selection buttons, number buttons or the like to set a cooking mode, a cooking time or the like. The temperature detection unit  522  detects an inside temperature of a cooking cavity  708 , as shown in FIG. 7, and provides the detected temperature to the control unit  502 . The storage unit  506  stores data required to cook the foods, such as cooking times according to the kinds of the foods, ON/OFF control modes of an upper heater  520  and lower heaters  526  and  528  or the like.  
         [0028]    The control unit  502  is connected at output terminals thereof to a magnetron drive unit  508 , a motor drive unit  512  and a heater drive unit  518 . The magnetron drive unit  508  drives a magnetron  510  to generate electromagnetic waves. The motor drive unit  512  drives a tray motor  514  so that a glass tray  516  positioned in the cooking cavity  708  is rotated. The heater drive unit  518  drives the upper heater  520  and the lower heaters  526  and  528 .  
         [0029]    [0029]FIG. 6 illustrates a control panel  600  of the microwave oven equipped with heaters of FIG. 5. As shown in FIG. 6, one of the cooking modes, such as a baking mode or a broiling mode, can be selected using only a single cooking mode selection button  602  so as to cook the food using the upper heater  520  and the lower heaters  526  and  528 , and the ON/OFF control mode of the upper heater  520  and the lower heaters  526  and  528 , which is suitable for the selected cooking mode, is automatically performed. In the microwave oven equipped with heaters, the ON/OFF control mode of the upper heater  520  and the lower heaters  526  and  528 , which is suitable for a corresponding accessory, is automatically performed by identifying a kind of accessory, such as a wire rack  720 , a crumb tray  714  or the like, present in the cooking cavity  708  based on a variation in an inside temperature of the cooking cavity  708  at an initial operating stage of the selected cooking mode.  
         [0030]    The ON/OFF control mode of the upper heater  520  and the lower heaters  526  and  528  is described in detail with reference to FIG. 7. FIG. 7 is a sectional view illustrating a heat conduction process according to the kinds of the accessories in the microwave oven equipped with heaters. As shown in FIG. 7, a crumb tray  714  used to bake bread, cookies and the like is inserted between the upper heater  520  and the lower heaters  526  and  528 . If the crumb tray  714  is inserted, as described above, heat generated by the upper heater  520  is not transmitted to a lower space  760 , but mainly remains in an upper space  750 . Since the temperature detection unit  522  is installed above the crumb tray  714 , the temperature detection unit  522  is very sensitive to a variation in the temperature of the upper space  750  of the crumb tray  714 . Thus, if an inclination of a temperature characteristic curve of the upper space  750  of the cooking cavity  708  is greater than that without the crumb tray  714  inserted in the cooking cavity  708 , it can be appreciated that the baking mode to bake the bread (cookies or the like)  770  using the crumb tray  714  is being performed. If the baking mode is performed as described above, the bread (cookies or the like)  770  rises to come excessively close to the upper heater  520 . Accordingly, the bread  770  must be prevented from being overcooked by controlling the upper heater  520  and the lower heaters  526  and  528  to be alternately switched ON and OFF.  
         [0031]    [0031]FIG. 8 is a graph illustrating inside temperature characteristics of the cooking cavity  708  of the microwave oven equipped with heaters of FIG. 5. As shown in FIG. 8, since the temperature of the upper space  750  of the cooking cavity  708  rapidly rises in the case of using the crumb tray  714 , the inclination of the temperature characteristic curve  802  is greater than an inclination of the temperature characteristic curve  804  in the case of using the wire rack  720 . Accordingly, the ON/OFF control mode of the upper heater  520  and the lower heaters  526  and  528  is determined by periodically detecting the temperature of the cooking cavity  708  through the temperature detection unit  522  during a simultaneous operation period of the upper heater  520  and the lower heaters  526  and  528  and obtaining the inclination of the temperature characteristic curve using the detected temperature, and determining whether the crumb tray  714  is used based on the obtained inclination.  
         [0032]    [0032]FIG. 9 is a flowchart illustrating a method of controlling the microwave oven equipped with heaters of FIG. 5. As shown in FIG. 9, if a cooking mode using the upper heater  520  and the lower heaters  526  and  528  is initiated at operation S 902 , the upper heater  520  and the lower heaters  526  and  528  are simultaneously operated at operation S 904 , so the inside of the cooking cavity  708  is heated. The inside temperature of the cooking cavity  708  is scanned during a simultaneous operation period of the upper heater  520  and the lower heaters  526  and  528  at operation S 906 , so the inclination of the temperature characteristic curve of the inside of the cooking cavity  708  is obtained at operation S 907 . If the simultaneous operation of the upper heater  520  and the lower heaters  526  and  528  is terminated at operation S 908 , whether the crumb tray  714  has been used is determined based on the obtained inclination of the temperature characteristic curve at operation S 910 . If the crumb tray  714  has been used, the food is prevented from being overcooked by controlling the upper heater  520  and the lower heaters  526  and  528  to be alternately switched ON and OFF at operation S 912 . On the contrary, if the crumb tray  714  has not been used, the upper heater  520  and the lower heaters  526  and  528  are simultaneously switched ON or OFF at operation S 914 . If cooking is performed by the ON/OFF control mode of the upper heater  520  and the lower heaters  526  and  528  and a cooking time elapses at operation S 916 , the cooking mode is terminated.  
         [0033]    The microwave oven equipped with heaters in accordance with the present invention increases users&#39; convenience by identifying the kind of an accessory, such as a wire rack, a crumb tray or the like, present in a cooking cavity on the basis of a variation in the inner temperature of a cooking cavity at the initial operating stage of a cooking mode using heaters and automatically performing the ON/OFF control mode of the heaters suitable for the corresponding accessory.  
         [0034]    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 this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.