JP3672767B2 - microwave - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a microwave oven having an improved temperature detection configuration.
[0002]
[Problems to be solved by the invention]
  Conventionally, in a microwave oven, the temperature of food is detected by an infrared sensor, and the microwave generator is controlled according to the detection result. In this case, the infrared sensor is provided in the upper part of the upper part of the heating chamber so as to be movable in the lateral direction, and a sensor hole is formed in the upper plate part along the moving direction, and the infrared sensor is moved. The temperature in the heating chamber is detected over a relatively wide range through the sensor hole. However, this device requires a moving device that moves the infrared sensor exclusively, which increases the installation space and complicates the configuration, and increases the size and complexity of the overall configuration.
[0003]
  Further, as another configuration that eliminates the need for the moving device, a temperature detecting device in which a plurality of infrared sensor elements are arranged is fixedly disposed above the upper plate portion of the heating chamber and is opposed to the temperature detecting device. Some sensor holes are formed, and this temperature detection device detects the heating chamber in a relatively wide range. However, in this case, it is necessary to separate the element intervals to some extent so that the individual detection visual fields of the infrared sensor elements do not overlap so much, the temperature detection device is relatively large, and the installation space is widened, and the layout design is troublesome, In addition, there is a problem in that the overall configuration is increased in size and complexity. In addition, the directionality of each infrared sensor element needs to be accurate, resulting in uneven distribution of measurement points, and there is a possibility that temperature measurement accuracy is lowered and control reliability is lowered. Further, the sensor hole is large, and there is a problem of microwave leakage.
[0004]
  The present invention has been made in view of the above-described circumstances, and its purpose is to reduce the size of the temperature detection structure, to reduce the arrangement space and to facilitate the arrangement design, and to improve the temperature measurement accuracy. An object of the present invention is to provide a microwave oven capable of improving control reliability.
[0005]
[Means for Solving the Problems]
  The invention of claim 1 is a heating chamber in which food is stored;
  A rotating body provided in the heating chamber, on which the food is disposed;
  Driving means for rotating the rotating body;
  A microwave generator for heating the food by supplying microwaves to the heating chamber;
  A temperature detecting means in which a plurality of infrared sensor elements are arranged substantially linearly so as to have a detection field of view in the radial direction of the rotating body, and an imaging lens is provided on the incident portion side of the plurality of infrared sensor elements;
  The rotational body is driven to rotate, the detection result from each infrared sensor element of the temperature detecting means is measured for each predetermined rotation angle position, and based on the temperature measurement result at the measurement point for each predetermined rotation angle of each infrared sensor element. Temperature distribution detecting means for detecting a temperature distribution in the heating chamber;
  The number of foods is detected based on the number of times that the temperature measurement result at the measurement point obtained by this temperature distribution detection means shows a characteristic that rises and falls in the rotation direction of the rotating body or vice versa, And the drive of the said microwave generator is stopped in the required period which detects the said numberFood form detection means;
  Control means for performing heating control based on the detection result by the food form detection means;
  It is configured with.
[0006]
  In the first aspect of the present invention, the temperature detecting means is configured to arrange a plurality of infrared sensor elements and provide an imaging lens on the incident portion side of the plurality of infrared sensor elements. A wide detection field of view can be secured even if they are arranged close to each other, so that the temperature detection means can be reduced in size, the installation space can be reduced, and the arrangement design can be improved. Infrared rays from the heating chamber are optically incident on each infrared sensor element, so that the infrared rays at the measurement point can be guided well without requiring high directivity accuracy to each infrared sensor element. Unlike directing to the point to be measured directly, it is possible to improve the uniformity of the distribution of the measurement points, and to improve the temperature measurement accuracy and thus the control reliability. Kill as to become.
[0007]
  When food is placed on the rotating body and heated, the temperature of the food rises with respect to the temperature of the rotating body. Therefore, a temperature difference is observed between the food existing portion and the food covered portion. The number of foods can be detected by measuring the number of times the characteristic indicating the temperature difference appears (for example, one food in the case of one time).
[0008]
  However,Claim 1In the present invention, the number of times that the food form detection means shows the characteristic that the temperature measurement result of the measurement point obtained by the temperature distribution detection means rises and falls in the rotation direction of the rotating body or vice versa. Since the number of foods is detected based on this, the number of foods can be detected with high accuracy. In this case, the food form detecting means stops the driving of the microwave generator during the required period for detecting the number of foods. As a result, the accuracy of detecting the number of foods is improved.
[0009]
  The invention of claim 2 comprises a heating chamber in which food is stored,
  A rotating body provided in the heating chamber, on which the food is disposed;
  Driving means for rotating the rotating body;
  A microwave generator for heating the food by supplying microwaves to the heating chamber;
  A temperature detecting means in which a plurality of infrared sensor elements are arranged substantially linearly so as to have a detection field of view in the radial direction of the rotating body, and an imaging lens is provided on the incident portion side of the plurality of infrared sensor elements;
  The rotational body is driven to rotate, the detection result from each infrared sensor element of the temperature detecting means is measured for each predetermined rotation angle position, and based on the temperature measurement result at the measurement point for each predetermined rotation angle of each infrared sensor element. Temperature distribution detecting means for detecting a temperature distribution in the heating chamber;
  The number of foods is detected based on the number of times the temperature measurement result obtained by this temperature distribution detection means shows a characteristic that rises and falls in the rotation direction of the rotating body or vice versa.Food form detection means
  When the food form detection means detects that the number of foods is plural, a control means for calculating an average temperature of the maximum temperature of each food region and controlling the microwave generator according to the average temperature;
  It is configured with.
[0010]
  In the invention of claim 2,The number of foods based on the number of times the food form detection means shows the temperature measurement result at the measurement point obtained by the temperature distribution detection means ascending and descending in the rotating direction of the rotating body or vice versa. Therefore, the number of foods can be detected with high accuracy.
[0011]
  Further, when the food form detection means detects that the number of foods is plural, the control means calculates the average temperature of the maximum temperature of each food region and controls the microwave generator according to the average temperature. LikeSo, multipleThe food can be heated without excess or deficiency.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present inventionAbout reference examples to help understandingThis will be described with reference to FIGS. First, in FIG. 1, a main body 1 of a microwave oven is configured by disposing an inner box 3 as a box inside an outer box 2, and the inside of the inner box 3 is a heating chamber 4. . A motor 5 as drive means is disposed at the center lower portion of the outer surface of the bottom plate portion 4a of the heating chamber 4, and the upper end portion of the rotating shaft 6 penetrates the bottom plate portion 4a and is inside the heating chamber 4. Protruding.
[0013]
  The rotating shaft 6 is detachably attached so that a metal rotating body 7 can rotate integrally. On this rotating body 7, food is placed directly or via a rotating plate 8 made of heat-resistant glass, for example.
[0014]
  Furthermore, as shown in FIG. 2, for example, a rectangular excitation port 9 is formed in the bottom plate portion 4 a of the heating chamber 4. A space on the right side between the outer box 2 and the inner box 3 is a machine room 1a, and a magnetron 10 serving as a microwave generator is disposed in the machine room 1a. In this case, the antenna 10a faces downward.
[0015]
  Furthermore, a waveguide 11 is attached to the bottom plate portion 4a of the heating chamber 4, one end side of which surrounds the antenna 10a of the magnetron 10, and the other end side is the excitation. It is configured to communicate with the mouth 9.
[0016]
  On the other hand, as shown in FIG. 7, a position detecting device 12 as position detecting means is provided on the rotating shaft 6 portion of the motor 5. The position detection device 12 includes a photo interrupter 13 attached to the upper surface of the motor frame 5a, which is a non-rotating part, and a subject that is attached to the rotating shaft 6 via a disk 14 and detected by the photo interrupter 13. 15. In this case, the timing at which the subject 15 is detected by the photo interrupter 13 is the timing at which the specific position Ph of the rotating body 7 coincides with the specific position P4 of the heating chamber 4 as shown in FIG. This is called a position. In this case, the motor 5 is composed of a synchronous motor and is driven to rotate at a constant speed.
[0017]
  Further, in FIG. 1, a temperature sensor 16 serving as a temperature detecting means is disposed at the upper part of the machine room 1 a, and this temperature sensor 16 passes through a temperature detecting hole 17 formed in the side wall of the heating chamber 4. The surface temperature of the food in the heating chamber 4 is detected. The hole 17 is formed in the upper part of the concave portion 17a formed in the side wall of the inner box 3, and as shown in FIGS. 3 and 4, the hole 17 has a slit shape, and its length in the longitudinal direction is longer than that of the conventional case. It is set short. As shown in FIGS. 5 and 6, the temperature sensor 16 has infrared sensor elements 161 to 166 arranged in a line inside the sensor case 16 a, and on the incident part side of the infrared sensor elements 161 to 166. An imaging lens 19 is provided. In this case, the infrared sensor elements 161 to 166 are arranged along the radial direction of the rotating body 7, and the infrared sensor element 161 detects the central portion of the rotating body 7 or the rotating dish 8, and the infrared sensor. The outer peripheral side is detected in the order of the elements 162, 163, 164, 165, 166. The detection field of view of the infrared sensor elements 161 to 166 on the rotating dish 8 is as shown by reference numerals S1, S2, S3, S4, S5, and S6 in FIG.
[0018]
  The control circuit 18 includes a microcomputer, which detects a temperature distribution as follows. That is, the control circuit 18 has a timer function, and has the time th required for one rotation of the motor 5 at a constant speed as data. The control circuit 18 rotates the rotating body 7 at a constant speed, and based on the time count from the detection signal input of the photointerrupter 13 (the rotational angle position of the rotating body 7 is the initial position), “360 ° of the rotating body 7. / 16 "rotation angle position (see symbols a to p in FIG. 10). At each of the rotational angle positions, there are “1” to “6” measurement points in FIG. 10, and thus there are 64 measurement points P (i, j) as a whole. The point temperature T (i, j) (i = 1 to 6, j = a to p) from each of the infrared sensor elements 161 to 166 is taken in each time the rotation angle positions a to p are reached. This point temperature T (i, j), which is the temperature measurement result, is detected and stored as a temperature distribution by the control circuit 18. That is, 64 point temperatures T (i, j) are taken in by one rotation of the rotator 7, and the temperature distribution is detected.
[0019]
  In FIG. 3, signals from the photo interrupter 13, the temperature sensor 16, and the key input unit 20 are input to the control circuit 18. The key input unit 20 includes a cooking end temperature setting key and a start key as cooking end temperature setting means, and further includes keys such as a reset key. The control circuit 18 functions as a food form detection means for detecting the size (area) and number of foods, and also functions as a control means for controlling the magnetron 10 and the motor 5 and correcting the set temperature. .
[0020]
  The functions as the food form detection means and the control means will be described with reference to the flowcharts of FIGS. When the food is placed on the rotating body 7 via the rotating dish 8, the desired cooking end temperature Ts is set by operating the cooking end temperature setting key, and the start key is operated, the flowchart of FIG. 11 starts. That is, the control circuit 18 first drives the magnetron 10 to start heating, as shown in step V1, and rotates the rotating body 7 by energizing the motor 5.
[0021]
  And it transfers to step V2 and performs temperature distribution detection and food area detection. The details of step V2 are shown in the flowchart as a subroutine of FIG. In this flowchart, in step W1, temperature distribution detection is performed. That is, the point temperature T (i, j) detected by each of the infrared sensor elements 161 to 166 is read at each rotation angle position a to p while rotating the rotating body 7 once. In this case, FIG. 13 shows temperature changes of the point temperatures T (1, a) to T (6, a) of the infrared sensor elements 161 to 166 at the rotation angle position a. For example, FIG. 13 shows changes in point temperatures T (1, a) to T (6, a) when the food F is arranged at the center of the rotating body 7 and hence the rotating dish 8 as shown in FIG. Is shown. As can be seen from FIG. 13, since the food F exists in the detection visual fields S1 and S2 of the infrared sensor elements 161 and 162 on the center side, the point temperatures T (1, a) and T (2, a) are the other parts. The degree of temperature rise is larger than (the part without food).
[0022]
  In the next step W2, the maximum temperature and the minimum temperature are detected from the point temperatures T (1, a) to T (6, p) for one rotation, that is, the temperature distribution detected this time, and the difference is calculated. Thereafter, in step W3, it is determined whether or not the temperature difference is larger than 10 ° C. The purpose of this determination is based on the idea that when the temperature difference is 10 ° C. or more, it can be determined that there is food.
[0023]
  Thereafter, in step W4, an average temperature Tav of all point temperatures T (1, a) to T (6, p) is calculated as the reference temperature for determining the presence or absence of food. When it is determined whether each point temperature T (i, j) is higher than the average temperature Tav, the process proceeds to step W6, and the measurement point P (i, j) is a food existing area. And the measurement point P (i, j) is stored, and the parameter “1” indicating the presence of food is stored. When the point temperature T (i, j) is equal to or lower than the average temperature Tav, the process proceeds to step W7, where the measurement point P (i, j) is determined to be a food absent region and the measurement point P ( i, j) is stored and a parameter “0” indicating no food is stored.
[0024]
  When the comparison with the average temperature Tav is completed for all the point temperatures T (i, j) (determined in step W8), the process proceeds to step W9, and each measurement point P (i, j) in the food existing area is determined. Is multiplied by the area index K (i) to obtain the total, and the area S of the food is detected. The concept of the area index K (i) is as follows.
[0025]
  In other words, the area of the food may generally be obtained by multiplying the number of each measurement point P (i, j) in the food existing area by the area of the visual field area. However, as shown in FIG. 10, since the measurement points P (1, j) and P (2, j) of the infrared sensor elements 161 and 162 for detecting the rotation center side have a short rotational displacement distance, Therefore, [the number of measurement points with food × the area of the detection visual field area] is not the food area, and the actual food area is smaller than this. On the contrary, the infrared sensor elements 165 and 166 farther from the center of rotation have a longer rotational displacement distance between the measurement points, so that the overlap of the detection field of view is reduced, and therefore the measurement point P farther from the center of rotation. (Number of measurement points with food x area of detection visual field area) becomes closer to the actual food area as (i, j).
[0026]
  Consider thisThis reference exampleThen, as shown in FIG. 15, the area index K (i) that increases with increasing distance from the center of the rotating body 7 is set for each of the measurement points P (1, j) to P (6, j). For example, the measurement point P (1, j) in the central portion has an area coefficient of “1”, and becomes “3”, “5”, “7”, “9” as it becomes an outer measurement point, and the outermost side. The measurement point P (6, j) is set to “11”.
[0027]
  Thus, in step W9, the area S of the food is obtained.
  In the next step W10, based on the area S, the size of the food is determined to be one of three levels. That is, as shown in FIG. 16, when the area S is 50 to 90, the food size is determined to be “small”, when 91 to 140, “medium”, and when 141 to 240, “large”. Food “small” includes foods placed in a vertical container such as a cup, “medium” includes foods placed in a bowl, and “large” foods placed on a plate Is included.
[0028]
  Thereafter, the process proceeds to step V3 in FIG. 11 to determine whether the determined size is “large”, “medium”, or “small”, and “large”, “medium”, “small”. Accordingly, the cooking end temperature Ts set by the user is corrected (steps V4 to V6). For example, when the size of the food is “large”, the set cooking end temperature Ts is corrected to be lower (for example, lower by 2 ° C.). When the size of the food is “small”, the set cooking end temperature Ts is corrected to be higher (for example, higher by 2 ° C.). In the case of “medium”, no correction is made.
[0029]
  Thereafter, the process proceeds to step V7 to detect the temperature distribution, and in step V8, it is determined whether or not the maximum temperature of the detected temperature distributions exceeds the cooking end temperature Ts set or corrected at the present time. If it is determined and exceeded, the process proceeds to step V9, where the driving of the magnetron 10 is stopped, the driving of the motor 5 is stopped, and this heating control is ended.
[0030]
  like thisReference exampleThe temperature detection sensor 16 has a configuration in which a plurality of infrared sensor elements 161 to 166 are arranged and the imaging lens 19 is provided on the incident part side of the infrared sensor elements 161 to 166. Even if ˜166 are arranged close to each other, a wide range of detection field of view can be secured, so that the temperature detection sensor 16 can be reduced in size, the installation space can be reduced, and the arrangement design can be improved. Since the infrared rays from the heating chamber 4 are optically incident on the infrared sensor elements 161 to 166 by the imaging lens 19, the infrared rays at the measurement points are excellent without requiring high directivity accuracy for the infrared sensor elements 161 to 166. Unlike the case of directing each infrared sensor element directly to the point to be measured, it improves the uniformity of the measurement point distribution. Bets are made, it is possible to improve the increase thus controlling the reliability of the temperature measurement accuracy.
[0031]
  Also,This reference exampleAccording to the above, the rotating body 7 is driven to rotate, the detection results from the infrared sensor elements 161 to 166 of the temperature sensor 16 are measured at each predetermined rotation angle position (360/16 [degree]), and the plurality of measurement points are measured. Since the temperature distribution is detected based on the point temperature T (i, j) at P (i, j), even if the number of the infrared sensor elements 161 to 166 is small, almost the entire temperature distribution of the heating chamber 4. Can be detected satisfactorily.
[0032]
  further,This reference exampleIs set for each measurement point P (i, j) of each of the infrared sensor elements 161 to 166, and an area index K (i) that increases as the distance from the center of the rotating body increases. The point temperature T (i, j) in j) is compared with the average temperature Tav which is the reference temperature for determining the presence or absence of food, thereby detecting the measurement point where the food exists, and the area index K (i) for each measurement point Since the area of the food is detected by summing, the area of the food can be detected with high accuracy.
  Furthermore,This reference exampleAccording to the above, since the position detection device 12 for detecting the rotation reference position of the rotating body 7 is provided, the rotation angle position detection of the rotating body 7 becomes accurate, and the temperature distribution detection can always be started from a predetermined angular position. And accurate temperature distribution can be detected.
[0033]
  By the way, the temperature sensor 16 is configured to detect the temperature in the heating chamber 4 from the outside of the heating chamber 4 through the hole 17. In this case, if the hole 17 is large, the microwave in the heating chamber 14 may leak out. There is butThis reference exampleThen, since the temperature detection sensor 16 optically causes the infrared rays from the heating chamber 4 to be incident on the infrared sensor elements 161 to 166 by the imaging lens 19, the hole 17 may be a small slit-like hole. Leakage can be prevented.
[0034]
  17 to 20 show the present invention.FirstIn this embodiment, the food is based on the number of times that the point temperature T (i, j) obtained by the temperature distribution detection shows a characteristic of rising and falling in the rotating direction of the rotating body 7. It is characterized in that it detects the number of. That is, in Step X1 of the flowchart of FIG. 17, the magnetron 10 is driven to start heating, and the motor 5 is energized to rotate the rotating body 7.
  And it transfers to step X2 and temperature distribution detection and the number-of-foods detection are performed. Details of this step X2 are shown in the flowchart as a subroutine of FIG. In this flowchart, Step Y1 to Step Y3 are the same as Step W1 to Step SW3 described above, that is, the presence or absence of food is determined.
[0035]
  In the next step Y4, the driving of the magnetron 10 is stopped and the driving of the motor 5 is stopped, and in step Y5, the average temperature Tn of the detected temperatures of the infrared sensor elements 161 to 165 at the respective rotation angle positions a to p. (X) is calculated. In this case, x is a variable 1 to 16 corresponding to the rotation angle positions a to p. For example, when the food contained in the cup is placed as a food on the center of the rotating dish 8 (see, for example, FIG. 14), as shown in FIG. The temperature Tn (x) is uniform (no temperature difference). Further, when a plurality of (three in this case) foods are placed on one rotating dish 8 as food, the average temperature Tn (x) varies.
[0036]
  In steps Y6 to Y10, the number of times indicating the characteristic that the average temperature Tn (x) rises and falls as the rotation angle position changes from a to p is detected. That is, in step Y7, a temperature difference before and after each rotation angle position a to p is calculated, and in step Y8, whether the temperature difference increases at a temperature range of 2 ° C. or more and decreases at a temperature range of 2 ° C. or more. If it is determined whether or not the temperature has risen and lowered by 2 ° C. or more, the process proceeds to step Y9 to increment the number of parameters N. This is performed 16 times (determined in step Y10), and the number of foods is detected by the parameter N. That is, when the parameter N is “0” or “1”, the number of foods is detected as “1”, and when N is “2” or more, it is determined that the number of foods is “N”. Here, in the case of FIG. 19, the number is “1”, and in the case of FIG. 20, the rise and fall by 2 ° C. or more at x = 3, 9, 15 (that is, the rotation angle positions c, i, o). Is detected, the number of food items is detected as “3”.
[0037]
  And it transfers to step Y12 and the magnetron 10 and the motor 5 are driven.
  Thereafter, the process returns to Step X3 in FIG. 17 to determine whether or not the number is plural. When there are plural pieces, the process proceeds to Step X4, Step X5, and Step X6. The purpose of step X4 to step X6 is to detect the maximum temperature of the three food regions, calculate the average temperature thereof, and if this average temperature is equal to or higher than the set cooking end temperature Ts, the process proceeds to step X7. Then, the driving of the magnetron 10 and the motor 5 is stopped, and this heating control is finished. In this embodiment, the characteristic of rising and falling in the rotation direction of the rotating body 7 is detected, but this may be detected in the opposite direction.
[0038]
  thisFirstAccording to the embodiment, the characteristics in which the average temperature of each of the infrared sensor elements 161 to 166 at each rotation angle position a to p rises and falls in the rotation direction of the rotating body 7 or vice versa are shown. Since the number of foods is detected based on the number of times N, the number of foods can be detected with high accuracy.
  Further, according to this embodiment, as can be seen from step Y4 and step Y12, since the driving of the magnetron 10 is stopped in the required period for detecting the number of foods, the food temperature change is small in the required period. Thus, the above characteristics appear accurately, and the detection accuracy of the number of foods is improved.
[0039]
  Furthermore, according to this embodiment, when it is detected that the number of foods is plural, the average temperature of the maximum temperature of each food region is calculated, and when the set cooking end temperature Ts reaches this average temperature, the magnetron is calculated. Since 10 is controlled to stop, a plurality of foods can be heated without excess or deficiency.
  That is, when there are a plurality of foods, the degree of heating may be different between one food and the other. In this case, if the control of stopping the driving of the magnetron 10 when the higher food temperature reaches the set cooking end temperature, heating of the other food becomes insufficient. Conversely, if the heating control is performed based on the other food having a low food temperature, one food may be overheated. However, this is not the case in this embodiment.
[0040]
  The present invention is not limited to the above embodiments, and may be implemented as follows.
  When it is detected that the area of the food is greater than or equal to a certain value, the average temperature of the food may be calculated, and the microwave generator may be controlled according to the average temperature. The purpose of this is as follows. That is, when the size of the food is large, a large number of foods may be included (for example, a relatively large food includes a commercially available lunch box). In this case, if the heating control is performed based on a portion having a high temperature (for example, if the microwave generator is stopped when the temperature reaches a set temperature), the other portions are not sufficiently heated. End up.
  However, by calculating the average temperature of the food and controlling the microwave generator according to the average temperature, it is possible to prevent insufficient heating in the entire food.
[0041]
  When the cooking end temperature Ts is set by the cooking end temperature setting key, the end determination reference temperature Ts ′ is set for each infrared sensor in accordance with the set cooking end temperature Ts (of the present invention).Second21), the driving of the magnetron 10 may be stopped when any of the infrared sensor elements 161 to 166 reaches the end determination reference temperature Ts ′.
[0042]
  The purpose of this is as follows. In other words, if the cooking end temperature Ts is set on the user side and heating is stopped when the detected temperature of the food reaches the cooking end temperature Ts, cooking can be performed at the user's preferred temperature. . However, each of the infrared sensor elements 161 to 166 may detect a temperature lower than the actual temperature if the distance to the detection target is long. When the temperature sensor 16 is configured to be present obliquely above the rotating body 7, the infrared sensor element 161 that detects a portion near the center of the rotating body 7 has a stronger tendency than other infrared sensor elements. That is, when the set cooking end temperature Ts is 60 ° C., even if the actual food temperature is 60 ° C., the detection temperature of the infrared sensor element 161 is 58 ° C., and the heating operation is not stopped. When the detected temperature reaches 60 ° C. and the heating operation is stopped, the temperature of the food already exceeds 60 ° C.
[0043]
  However, the above-described configuration can prevent the food from being overheated.
  Furthermore, the present inventionThird22, when the high temperature Th is detected in the portion H other than the central portion of the rotating body 7, the temperature rise degree ΔT of the high temperature portion H during the rotation of the rotating body 7 is detected. From the temperature Th of the high temperature portion H and the temperature increase ΔT, the rotational angle position of the rotating body 7 where the high temperature portion H reaches the set cooking end temperature Ts is determined. The drive of the magnetron 10 may be controlled to stop at the rotation angle position. The temperature rise ΔT is calculated from the temperature difference during one rotation of the high temperature portion H. If the detected temperature of the high temperature portion H this time is Tx, the temperature Tx ′ of the portion H after the next one rotation is
  Tx ′ = Tx + ΔT × th
It becomes. When it is determined that Tx ′ exceeds the cooking end temperature Ts (timing t0 in FIG. 23), the time tp for Tx to reach the cooking end temperature Ts is determined.
  tp = (Ts−Tx) / ΔT
Calculate with Accordingly, when the time tp has elapsed from the timing t0, the driving of the magnetron 10 is stopped.
[0044]
  The purpose of such control is as follows. That is, when the cooking end temperature Ts is set on the user side and heating is stopped when the detected temperature of the food reaches the cooking end temperature Ts, the temperature Tx of the highest portion H of the food is the cooking end temperature. It is preferable to stop the heating when Ts is reached. However, if the high temperature portion H exists in a portion other than the central portion of the rotating body 7, the temperature can be detected only at a timing of 1 degree per rotation of the rotating body 7, and at this detection timing, the temperature is less than the cooking end temperature Ts. However, at the next detection timing, it is considered that the cooking end temperature Ts has already been exceeded, and even if the heating is stopped, the heating is excessive. Such a problem also arises when a high-temperature portion appears in the peripheral portion of the food, or when the food contained in a relatively small container such as a cup is placed in the peripheral portion of the rotating body.
  However, in this embodiment, the above-described control is performed when the food reaches the cooking end temperature Ts even if the temperature detection timing for the high temperature portion H can be obtained only once per rotation. Can be stopped, and overheating can be reliably prevented.
[0045]
【The invention's effect】
  As apparent from the above description, the present invention can obtain the following effects.
  According to the first aspect of the present invention, the temperature detecting means is configured to arrange a plurality of infrared sensor elements and provide an imaging lens on the incident portion side of the plurality of infrared sensor elements. It is possible to reduce the size of the temperature detection means while reducing the installation space and improve the layout design. Also, it is possible to improve the uniformity of the distribution of the measurement points, thereby improving the temperature measurement accuracy and control. Reliability can be improved. Further, the rotating body is driven to rotate, the detection result from each infrared sensor element of the temperature detecting means is measured at each predetermined rotation angle position, and the temperature distribution is detected based on the temperature measurement results at the plurality of measurement points. Therefore, even if the number of infrared sensor elements is small, almost the entire temperature distribution in the heating chamber can be detected well.The further,The number of foods is detected based on the number of times the temperature measurement result of the measurement point obtained by the temperature distribution detection means shows a characteristic that rises and falls in the rotation direction of the rotating body or vice versa. Therefore, the number of foods can be detected with high accuracy. In addition, since the driving of the microwave generator is stopped in the required period for detecting the number of foods, the food temperature change is small in the required period, and the detection accuracy of the number of foods is improved.
[0046]
  Claim 2According to the invention, the number of foods based on the number of times that the temperature measurement result of the measurement point obtained by the temperature distribution detecting means showed a characteristic that rises and falls in the rotation direction of the rotating body or vice versa. The number of foods can be detected with high accuracy. Moreover, when the food form detection means detects that the number of foods is plural, the average temperature of the maximum temperature of each food area is calculated, and the microwave generator is controlled according to the average temperature. Therefore, multiple foods can be heated without excess or deficiency.
[Brief description of the drawings]
FIG. 1 shows the present invention.Reference examples to help understandFront view of a microwave oven
[Fig.2] Transverse plan view of microwave oven
Fig. 3 Front view of temperature sensor and hole
FIG. 4 is a perspective view from below of the hole portion.
[Fig.5] Vertical side view of temperature sensor
FIG. 6 is a front view of a temperature sensor.
FIG. 7 is a perspective view of a position detection device.
[Figure 8] Diagram showing the electrical system
FIG. 9 is a view showing a detection visual field of each infrared sensor element
FIG. 10 shows measurement points
FIG. 11 is a flowchart showing control contents.
FIG. 12 is a flowchart showing the control content of step V2 of FIG.
FIG. 13 is a diagram showing a temperature change of each infrared sensor element at a rotation angle position a.
FIG. 14 is a diagram for showing an example of a food shape
FIG. 15 is a diagram showing an area index.
FIG. 16 is a diagram showing the relationship between the detection area and the size of food.
FIG. 17 shows the present invention.FirstOf control contents showing an embodiment of the present invention
FIG. 18 is a flowchart showing the control content of step X2 in FIG.
FIG. 19 is a diagram showing a state of average temperature at a rotation angle position in a certain food arrangement state.
FIG. 20 is a diagram showing the state of the average temperature at the rotation angle position in another food arrangement state
FIG. 21 shows the present invention.SecondThe figure which shows the Example of this and shows the relationship between preset cooking completion temperature and completion | finish determination reference | standard temperature of each infrared sensor element
FIG. 22 shows the present invention.ThirdShowing the position of the high temperature part
FIG. 23 is a diagram showing a temperature change in a high temperature portion.
[Explanation of symbols]
  3 is an inner box (box body), 4 is a heating chamber, 5 is a motor (driving means), 7 is a rotating body, 8 is a rotating plate, 10 is a magnetron (microwave generator), 12 is a position detection device (position detection) Means), 16 is a temperature sensor (temperature detection means), 17 is a hole, 18 is a control circuit (temperature distribution detection means, food form detection means, control means), and 19 is an imaging lens.

Claims (2)

A heating chamber in which food is stored;
A rotating body provided in the heating chamber, on which the food is disposed;
Driving means for rotating the rotating body;
A microwave generator for heating the food by supplying microwaves to the heating chamber;
A temperature detecting means in which a plurality of infrared sensor elements are arranged substantially linearly so as to have a detection field of view in the radial direction of the rotating body, and an imaging lens is provided on the incident portion side of the plurality of infrared sensor elements;
The rotational body is driven to rotate, the detection result from each infrared sensor element of the temperature detecting means is measured for each predetermined rotation angle position, and based on the temperature measurement result at the measurement point for each predetermined rotation angle of each infrared sensor element. Temperature distribution detecting means for detecting a temperature distribution in the heating chamber;
The number of foods is detected based on the number of times that the temperature measurement result at the measurement point obtained by this temperature distribution detection means shows a characteristic that rises and falls in the rotation direction of the rotating body or vice versa, And the food form detection means for stopping the driving of the microwave generator in the required period of detecting the number ,
A microwave oven comprising: control means for performing heating control based on a detection result by the food form detection means. A heating chamber in which food is stored;
A rotating body provided in the heating chamber, on which the food is disposed;
Driving means for rotating the rotating body;
A microwave generator for heating the food by supplying microwaves to the heating chamber;
A temperature detecting means in which a plurality of infrared sensor elements are arranged substantially linearly so as to have a detection field of view in the radial direction of the rotating body, and an imaging lens is provided on the incident portion side of the plurality of infrared sensor elements;
The rotational body is driven to rotate, the detection result from each infrared sensor element of the temperature detecting means is measured for each predetermined rotation angle position, and based on the temperature measurement result at the measurement point for each predetermined rotation angle of each infrared sensor element. Temperature distribution detecting means for detecting a temperature distribution in the heating chamber;
A food that detects the number of foods based on the number of times that the temperature measurement result of the measurement point obtained by this temperature distribution detection means shows a characteristic that rises and falls in the rotating direction of the rotating body or vice versa Morphological detection means;
When the food form detection means detects that the number of foods is plural, a control means for calculating an average temperature of the maximum temperature of each food region and controlling the microwave generator according to the average temperature; A microwave oven comprising

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