JP2007184178A - Induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating device continuing heating only when a temperature of a cooking pot can be detected by an infrared-ray sensor. <P>SOLUTION: The induction heating device is formed so that a heat control means 6 stops the heating of the cooking pot 1 or controls so as to restrain amount of heating power when the cooking pot is not detected by a cooking pot detection means 7, by the above, the induction heating device with high safety can be realized by preventing the cooking pot from such a case that the infrared-ray sensor can not detect the temperature and the cooking pot becomes high temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an induction heating device used in general homes, offices, restaurants and the like.

  Conventionally, as shown in FIG. 11, this type of induction heating apparatus includes a top plate 2 on which a cooking container 1 is placed, a heating coil 3 disposed below the top plate 2, and the cooking container 1. Infrared sensor 4 disposed opposite to the bottom of the slab, temperature detecting means 5 for converting the received light energy of the infrared sensor 4 into temperature, and heating control for inductively heating the cooking vessel 1 by passing a high-frequency current through the heating coil 3 Means 8 are provided. A plurality of infrared sensors 4 may be provided (see, for example, Patent Document 1).

When heating is started, a high frequency magnetic field is generated from the heating coil 3 by a signal from the heating control means 8. The cooking vessel 1 is heated by this high frequency magnetic field and the temperature rises. The temperature of the cooking container 1 is measured by the infrared sensor 4 and converted into a temperature by the temperature detection means 5, and the heating control means 8 controls the heating amount based on the result.
JP 2003-109736 A

  However, in the conventional configuration, when the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, the temperature can be detected correctly, but when the bottom of the cooking container 1 deviates from the detection area of the infrared sensor 4. The infrared energy from the cooking container 1 is reduced and the infrared sensor 4 receives disturbance light such as visible light around the cooking container 1, so that the S / N ratio is deteriorated and the temperature detection error is large. Had the problem of becoming.

  The present invention solves the above-described conventional problems, and determines whether or not the bottom of the cooking container 1 covers the detection area of the infrared sensor 4 by detecting the ambient illuminance of the detection unit of the infrared sensor 4. When the cover is not covered, there are many errors in the temperature detected by the temperature detection means 5, and control is performed so that heating is stopped or the amount of heating power is suppressed so that an accident such as ignition does not occur because the cooking vessel 1 becomes hot. An object of the present invention is to provide a highly safe induction heating apparatus.

  In order to solve the above-described conventional problems, the induction cooking device of the present invention is provided with an illuminance sensor 6 for detecting the illuminance around the detection part of the infrared sensor 4.

  Accordingly, it is determined whether or not there is a possibility that energy from other than the cooking container 1 enters the infrared sensor 4, and when it is determined that the infrared sensor 4 may receive energy from other than the cooking container 1. Can detect that the cooking container 1 is placed at a position deviated from the detection range of the infrared sensor 4.

  In the induction heating cooker according to the present invention, the cooking container 1 is placed in a state where the temperature detection means 5 can correctly detect the temperature by determining whether or not the bottom of the cooking container 1 covers the detection area of the infrared sensor 4. If the temperature cannot be detected correctly, the cooking container 1 is heated to a temperature that is not intended by the user by controlling to stop heating or suppress the amount of heating power. It is possible to realize an induction heating apparatus that prevents the above-described problem and improves safety.

  A first invention is a cooking container for heating a cooked food, a top plate on which the cooking container is placed, a heating coil for generating an induction magnetic field to heat the cooking container, and cooking via the top plate An infrared sensor for detecting infrared radiation radiated from the container; temperature detection means for converting the temperature of the cooking container from energy received by the infrared sensor; and an illuminance sensor for detecting ambient illuminance of the detection unit of the infrared sensor; The cooking container detection means for determining the presence or absence of the cooking container from the energy received by the illuminance sensor, the detection result of the cooking container detection means and the temperature information of the temperature detection means to control the high-frequency current of the heating coil, and Heating control means for controlling the heating power amount of the cooking container, and when the cooking container is not detected by the cooking container detection means, When the heating control means is an induction heating device that controls to stop heating the cooking container or suppress the amount of heating power, when the ambient light enters the infrared sensor and it is determined that the detected temperature error is large By stopping heating or suppressing the amount of heating power, it becomes possible to prevent the cooking container from becoming too hot as the user does not intend.

  2nd invention eliminates the influence of the infrared rays from the cooking vessel 1 by setting it as the induction heating apparatus of Claim 1 which makes the sensitivity wavelength range of an illumination intensity sensor only a visible light range, and the detection part of an infrared sensor It becomes possible to accurately measure only the illuminance around.

  According to a third aspect of the invention, the sensitivity wavelength range of the infrared sensor does not include the visible light range, and the induction heating device according to claim 1 or 2 makes it possible to detect visible light as detected by the illuminance sensor. It is possible to accurately measure only the infrared rays from the cooking container 1 by eliminating the influence of ambient light.

  4th invention can measure the illumination intensity of the detection area of an infrared sensor more correctly by setting it as the induction heating apparatus of Claims 1-3 which makes the optical axis of an infrared sensor and an illumination intensity sensor the same direction. It becomes possible, and the detection accuracy of a cooking container can be improved.

  5th invention is equipped with an alerting | reporting means, and when the cooking container detection means discriminate | determines that there is no cooking container, or when the presence or absence of a cooking container cannot be determined, the said alerting | reporting means uses the induction heating apparatus to that effect. When the cooking container is not in the detection range of the infrared sensor, it is difficult to accurately measure the temperature by using the induction heating device according to any one of claims 1 to 4 to notify the user. By doing so, it is possible to inform the user that the cooking container is placed on the detection area of the infrared sensor or that the predetermined heating cannot be performed.

  According to a sixth aspect of the present invention, there is provided the induction heating device according to claim 1 in which a light guide means for guiding infrared rays from the cooking vessel is provided between the top plate and the infrared sensor, whereby the infrared energy from the cooking vessel is disturbed. The infrared sensor can be made to receive light without being affected by the influence of the light.

  7th invention can measure the illumination intensity of the detection area of an infrared sensor more correctly by setting it as the induction heating apparatus of Claim 6 which installs an illumination intensity sensor in the same light guide means as an infrared sensor. It becomes possible, and the detection accuracy of a cooking container can be improved.

  The eighth aspect of the invention is the induction heating apparatus according to any one of claims 1 to 7, wherein when the illuminance detected by the illuminance sensor is darker than a predetermined value, the cooking container detection means determines that the cooking container is present. Since it can be determined that the detection area of the infrared sensor covers the bottom of the cooking container, the infrared sensor can accurately receive infrared energy from the cooking container without being affected by ambient light. The temperature can be detected.

  The ninth invention provides a plurality of illuminance sensors, one illuminance sensor is installed in the same light guide means as the infrared sensor, and the other is installed outside the light guide means. By making the device to measure the illuminance in the detection area of the infrared sensor separately from the illuminance other than that, the bottom of the cooking container covers the detection part of the infrared sensor, and ambient light enters the detection part of the infrared sensor Whether or not it is possible to accurately determine whether or not the cooking container is detected.

  According to a tenth aspect of the present invention, when the illuminance sensor installed in the light guide unit is darker than the predetermined value and the illuminance sensor installed outside the light guide unit is brighter than the predetermined value, the cooking container detection unit cooks The induction heating device according to any one of claims 1 to 9, which determines that there is a container, so that it is possible to determine that the bottom of the cooking container covers the detection area of the infrared sensor. Can receive the infrared energy from the cooking container without being affected by disturbance light, so that the temperature can be accurately detected.

  In an eleventh aspect of the invention, when the illuminance sensor installed in the light guide means is darker than a predetermined value and the illuminance sensor installed outside the light guide means is darker than a predetermined value, the notification means The induction heating apparatus according to claim 10 that informs that the presence or absence cannot be detected, so that it cannot be determined whether or not the bottom of the cooking container covers the detection area of the infrared sensor, so heating is started or continued as it is. Then, the temperature detection means cannot detect the accurate temperature, and if the heating control is performed based on the inaccurate temperature information, the cooking container becomes dangerously high temperature unintended by the user, so that the fact is notified. By doing so, safety can be improved.

  According to a twelfth aspect of the present invention, the cooking container detection means detects the cooking container at least once before the heating control means starts heating. Since the heating is started after determining whether or not the temperature can be accurately detected even after starting, it is possible to realize a highly safe induction heating apparatus.

  In a thirteenth aspect of the present invention, when the heating control means is heating the cooking container, when the cooking container detection means determines that there is no cooking container, the heating control means stops the heating or suppresses the heating power amount. By using the induction heating device according to any one of claims 1 to 12 in which a time difference is provided, the position of the cooking container changes during cooking, and even when conditions for determining that there is no cooking container are complete, Therefore, it is possible to prevent a decrease in usability by providing a time for determining whether or not the cooking container has returned to the original position without changing the heating output immediately.

  In a fourteenth aspect of the present invention, the cooking container detection means detects the cooking container at least once within the time difference, thereby determining whether the cooking container has returned to its original position. It is possible to avoid malfunctions by determining a plurality of times and not making a determination in a temporary state.

  According to a fifteenth aspect of the present invention, there is provided an induction heating device according to claim 1 in which a portion where the heating coil is divided in the radial direction is provided, and an infrared sensor is disposed in a gap portion of the coil. Above all, it is possible to measure a place where the temperature is high, and it is possible to reduce an error when detecting that the cooking container is in a dangerous temperature range where oil is ignited.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a schematic configuration diagram of an induction heating apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is a cooking container, 2 is a top plate on which the cooking container 1 is placed, 3 is a heating coil disposed below the top plate 2, and 4 is disposed to face the bottom of the cooking container 1. The infrared sensor 5 is a temperature detecting means for converting the received light energy of the infrared sensor 4 into a temperature, 6 is an illuminance sensor for detecting the illuminance around the detection part of the infrared sensor, and 7 is the cooking container 1 from the energy received by the illuminance sensor 6. A cooking container detecting means 8 for determining the presence or absence of the heating container 8 is a heating control means for inductively heating the cooking container 1 by supplying a high-frequency current to the heating coil 3.

  About the induction heating apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, although not shown, when an instruction to start heating is issued to the induction heating device by an operation unit or the like connected to the heating control means 8, the heating control means 8 supplies a high-frequency current to the connected heating coil 3. . The cooking vessel 1 is placed on the top plate 2 above the heating coil 3 and is in a magnetically coupled state with the heating coil 3. A high-frequency magnetic field is generated from the heating coil 3 supplied with the high-frequency current, an eddy current due to electromagnetic induction flows in the cooking vessel 1, and the cooking vessel 1 is heated by the Joule heat.

  The infrared sensor 4 receives infrared rays emitted from the cooking container 1 through the top plate 2, and the information is sent to the temperature detection means 5. The temperature detection means 5 calculates the temperature of the cooking container 1 from the amount of energy received by the infrared sensor 4 and sends the temperature information to the heating control means 8.

  The heating control unit 8 controls the heating power amount designated by the user, while suppressing the heating power amount or stopping the heating depending on the temperature information obtained from the temperature detection unit 5. For example, when the heating operation is started in a mode for cooking fried food, the amount of heating power is controlled so that the cooking container 1 is maintained at a predetermined temperature, or when the cooking container 1 is performing normal heating. When the temperature is abnormally high, the amount of heating power is suppressed or the heating is stopped to ensure safety so that there is no oil ignition. The heating control means 8 and the temperature detection means 5 may be integrated, and a DSP or a microcomputer is often used, but is not limited thereto, and may be a custom IC. .

  Here, the cooking vessel 1 is magnetically coupled to the heating coil 3 and is usually made of a magnetic material. Copper and aluminum, which are non-magnetic and low resistance metals, cannot be heated with a normal induction heating device, but recently, a method that can heat even a low resistance metal has been put to practical use. It may be a resistance metal cooking container. Moreover, when the diameter of the cooking container 1 is small, or when there exists a big gap between the top plate 2 and the cooking container 1, it is designed so that it cannot heat.

  The top plate 2 is a part that forms the appearance of the induction heating device, and is where the cooking container 1 is placed. The top plate 2 is made of heat-resistant tempered glass or the like, and since it is flat, it is excellent in terms of ease of cleaning and aesthetics, and is one of the advantages of the induction heating device.

  The infrared sensor 4 receives infrared rays emitted from the cooking container 1. In the conventional induction heating apparatus, a contact type temperature sensor such as a thermocouple or a thermistor attached so as to be in contact with the lower portion of the top plate 2 is used. In that case, the upper part of the top plate 2 is warmed by heat conduction and radiant heat at the part where the bottom part of the cooking container 1 and the top plate 2 are in contact, and the heat is conducted toward the lower part of the top plate 2, and the temperature is reduced. Will be measured. In this case, since the temperature at the bottom of the cooking container 1 is indirectly measured through the top plate 2, it depends on the size of the contact area between the cooking container 1 and the top plate 2, the heat capacity of the top plate 2, and the like. There existed a subject that the responsiveness with respect to the temperature fluctuation of the cooking vessel 1 was bad. However, in the case of the infrared sensor 4, since infrared rays from the cooking container 1 are directly received by the infrared sensor 4, cooking is not affected by the size of the contact area between the cooking container 1 and the top plate 2 or the heat capacity of the top plate 2. There is an advantage that it reacts immediately to the temperature fluctuation of the container 1.

  Thereby, for example, when heating is performed in a state where there is no cooked food in the cooking container 1, the temperature of the cooking container 1 rapidly increases. There is a safety device that prevents the cooking container 1 from reaching the ignition point of the oil because there is a possibility that it will ignite when the oil is dropped into it. In the conventional induction heating apparatus, since there is a delay with respect to the temperature fluctuation of the cooking vessel 1 as described above, ignition is prevented as a design having a sufficient margin with respect to the ignition temperature of oil. However, the function may function even when preheating the frying pan, and the usability may be deteriorated. However, when the infrared sensor 4 is used, it is not necessary to see a margin for a delay in the thermal response, so that such a situation can be avoided.

  The temperature detection means 5 converts the output of the infrared sensor 4 into a temperature. The energy received by the infrared sensor 4 is converted into a voltage, current, or frequency determined by the energy and output. The temperature detection means 5 converts these physical quantities into temperatures and uses them as information necessary for controlling the heating power. The temperature detection means 5 has a function of inputting a physical quantity of the infrared sensor 4, a calculation function of converting the physical quantity into temperature, and a function of outputting the converted temperature. The converted temperature information is sent to the heating control means 8, and various controls are performed according to the temperature.

  This method has no problem when the detection area of the infrared sensor 4 is entirely covered by the bottom of the cooking container 1 and the energy detected by the infrared sensor 4 is all infrared energy from the cooking container 1. However, if there is a part of the detection area of the infrared sensor 4 where the bottom of the cooking container 1 is not covered, disturbance light enters from that part, and the infrared sensor 4 receives the energy of the disturbance light. Since the energy of disturbance light is larger than the infrared energy radiated from the cooking container 1, the infrared energy from the cooking container 1 cannot be detected.

  In order to avoid such a situation, in the present invention, induction heating provided with cooking container detection means 7 for determining the presence or absence of the cooking container 1 from the energy received by the illuminance sensor 6 for detecting the illuminance around the detection part of the infrared sensor 4 is provided. It is a device.

  The illuminance sensor 6 is for detecting the illuminance around the detection part of the infrared sensor. Although the illuminance sensor 6 has a characteristic that matches the human visual sensitivity, it does not have to be that particular.

  The cooking container detection means 7 determines the presence or absence of the cooking container 1 from the energy received by the illuminance sensor 6.

  The detection method of a cooking container is demonstrated using FIG.

  In STEP1, the energy received by the illuminance sensor 6 is measured. The measured value is V1.

  In STEP2, the magnitude of V1 measured by the illuminance sensor 6 and the determination value α are compared. The determination value α will be described with reference to FIG. The infrared sensor 4 detects when the infrared sensor 4 is placed in an environment with a certain illuminance β with respect to the energy a detected by the infrared sensor 4 when the infrared sensor 4 is placed in a dark state and not receiving disturbance light energy. The illuminance is increased to a level at which the illuminance sensor 6 and the cooking device detection means 7 receiving the output can detect that a difference (b−a) has occurred between the energy b and the energy of the infrared sensor 4 becomes b. Α is set as a value obtained by adding a variation element and a margin to the illuminance β. When V1> α, there is sufficient illuminance around the cooking container 1, so if the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, It can be considered that the infrared sensor 4 is placed in a state where the light enters the detection area of the infrared sensor 4 as disturbance light, and the infrared sensor 4 receives the light to increase the received light energy.

  In STEP 3, it is considered that there is a possibility that light around the cooking container 1 enters as disturbance light and receives infrared energy from V1> α. That is, there is a possibility that the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, and detecting the light other than the infrared energy from the cooking container 1 deteriorates the S / N ratio and accurately detects the temperature. It may not be possible. Therefore, it is determined that there is no cooking container 1 in such a state, and control is performed so that heating of the cooking container 1 is stopped or the amount of heating power is suppressed.

  Or since the bottom part of the cooking container 1 has covered the detection area of the infrared sensor 4, and the cooking container 1 has become more than predetermined | prescribed temperature, the infrared sensor 4 may receive infrared energy. Since these cannot be distinguished from each other, the control may be such that the user of the induction heating device is notified that the presence or absence of the cooking container 1 cannot be determined.

  Since STEP4 is a condition of V1 <α, the infrared sensor 4 is the same as a state where it is placed in a dark state. That is, the infrared sensor 4 is in a state in which neither the infrared energy from the cooking container 1 nor the energy of ambient disturbance light is received. Accordingly, the bottom of the cooking container 1 covers the detection area of the infrared sensor 4 and the infrared energy from the cooking container 1 can be received. The temperature detecting means 5 can accurately calculate the temperature from the energy received by the infrared sensor 4.

  However, even when the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, the infrared sensor 4 may not receive infrared energy because the illuminance around the cooking container 1 is β or less. It is thought that there is. In that case, since the amount of infrared energy that can be detected by the infrared sensor 4 is reduced as compared with the case where the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, the temperature may not be detected accurately. . Since these cannot be distinguished from each other, the control may be such that the user of the induction heating device is notified that the presence or absence of the cooking container 1 cannot be determined.

  By doing so, the conventional infrared sensor 4 alone has a problem that the accurate temperature cannot be measured when the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4. As in the present invention, the cooking container detection means 7 determines the presence or absence of the cooking container 1 and determines whether or not an accurate temperature can be detected. An induction heating apparatus that can avoid dangerous situations such as deformation or breakage of the container 1 or ignition of oil can be provided, and benefits can be provided to the user.

  The temperature detection means 5, the cooking container detection means 7, and the heating control means 8 are each often a DSP, a microcomputer, or the like, but are not limited thereto, and may be a custom IC. These functions may be shared by a single microcomputer or the like.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content of the invention described in the second embodiment is an induction heating device in which the sensitivity wavelength range of the illuminance sensor is only the visible light range.

  The temperature detection range required for the temperature detection means mounted on the induction heating device is about 350 to 400 ° C. Since the ignition temperature of oil is about 330 to 350 ° C., it is possible to provide a safe induction heating device that is free from the risk of oil ignition if the cooking vessel 1 can be controlled so as not to reach that temperature. Because. Of course, it may be a temperature detecting means capable of measuring even a higher temperature range.

  As shown in FIG. 4, the infrared energy radiated from the object has energy on the short wavelength side as the temperature increases. The temperature range desired to be detected by the induction heating device is about 330 to 350 ° C., but in this temperature range, the visible light range is about 700 nm, so the visible light range and the wavelength range where infrared energy is emitted are almost separated. be able to.

  There are various types of illuminance sensors 6, and some have characteristics that match the human visual sensitivity, and others have sensitivity in places other than the visible light region, that is, in places of 700 nm or more. Here, if the illuminance sensor 6 having sensitivity at 700 nm or more is used, if the cooking vessel 1 is radiating infrared energy at a high temperature, the illuminance sensor 6 will react with the energy. Become. Since it is desirable that the illuminance sensor 6 is not affected by the temperature state of the cooking vessel 1, the illuminance sensor 6 can measure the illuminance without being affected by limiting the sensitivity wavelength region to only the visible light region. It is possible to increase the accuracy of discrimination of the cooking container detection means 7.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The invention described in the third embodiment is an induction heating apparatus in which the sensitivity wavelength range of the infrared sensor does not include the visible light range.

  As described in the second embodiment, by dividing the infrared energy from the cooking container 1 and the visible light region, the illuminance sensor 6 and the infrared sensor 4 can detect each with high accuracy.

  In many cases, the infrared sensor 4 capable of receiving infrared energy of 700 to 1100 nm has sensitivity in a wavelength region of 700 nm or less. In such a case, almost the same characteristics can be obtained by using a filter that cuts the visible light range, so such a configuration may be used.

  Since the infrared sensor 4 does not have sensitivity in the visible light region, it can receive infrared energy from the cooking container 1 without being affected by visible light energy from the surroundings of the cooking container 1, and thus the S / N ratio. Thus, an error in temperature calculated by the temperature detecting means 5 is reduced, and a highly safe induction heating apparatus can be provided.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The invention described in the fourth embodiment is an induction heating apparatus according to which the optical axes of the infrared sensor and the illuminance sensor are in the same direction.

  The illuminance sensor 6 is for measuring the illuminance around the detection part of the infrared sensor 4, but for the purpose of installing the illuminance sensor 6, when the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, This is because the level of disturbance light entering the detection unit of the infrared sensor 4 is measured, and the cooking container detection means 7 detects the presence or absence of the cooking container based on the information.

  Therefore, as shown in FIG. 5, if the optical axes of the illuminance sensor 6 and the infrared sensor 4 are deviated, the level of disturbance light cannot be measured accurately, and the determination accuracy of the cooking container detection means 7 is lowered.

  Therefore, by installing the illuminance sensor 6 and the infrared sensor 4 so that the optical axes thereof are in the same direction and increasing the determination accuracy of the cooking container detection means 7, a more secure induction heating device can be provided.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content of the invention described in the fifth embodiment is provided with notification means, and when the cooking container detection means determines that there is no cooking container, or when the presence or absence of the cooking container cannot be determined, the notification means This is an induction heating device for notifying the user of the induction heating device.

  When the cooking container 1 is not present, the infrared sensor 4 cannot receive the infrared energy from the cooking container 1, so the temperature detection means 5 determines that the temperature of the cooking container 1 has not risen. However, since the temperature of the cooking container 1 has risen, there is a possibility that it becomes a dangerous state such as deformation of the pan or ignition of oil. In addition, even when it is not possible to determine whether or not the cooking container 1 is present, if the cooking container 1 is not actually present, the same thing can occur, so that it is dangerous to heat.

  In such a case, in order to heat, the place where the cooking container 1 is placed on the top plate 2 is changed, and the detection area of the infrared sensor 4 is re-installed so that the bottom of the cooking container 1 covers it. There is no other way. Therefore, the notification means 9 notifies the user that the cooking container 1 cannot be detected, and prompts the user to reposition the cooking container 1.

  The notification means 9 is typically visual or auditory, but may be other than that. As visual things, lamps such as light emitting diodes and display devices such as liquid crystals are often used, but the present invention is not limited thereto. Moreover, although there are many auditory things such as a buzzer, a melody, and voice guidance, it is not limited thereto.

(Embodiment 6)
Next, a sixth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content of the invention described in the sixth embodiment is an induction heating apparatus in which light guide means for guiding infrared rays from a cooking container is provided between a top plate and an infrared sensor.

  As shown in FIG. 1, the infrared sensor is disposed in a cylindrical light guide 10, and the light guide 10 extends in the optical axis direction of the infrared sensor 4. The light guide means 10 is configured so as to pass through the gap of the heating coil 3 and to the vicinity of the top plate 2.

  By adopting such a configuration, it is possible to prevent the infrared energy from the cooking container 1 from being scattered without reaching the light receiving portion of the infrared sensor 4, and from ambient light from the surroundings of the cooking container 1 and the heating coil. It is possible to prevent the infrared sensor 4 from receiving the infrared energy or the like and to prevent the S / N ratio from deteriorating. By doing so, the temperature error calculated by the temperature detecting means 5 is reduced, and a highly safe induction heating apparatus can be provided.

  The light guide means 10 may be a resin material or a metal material, but when a metal material is used, consideration should be given so that the light guide means 10 is not induction-heated. In the case of a resin material, it is necessary to select a material having temperature characteristics that can withstand radiant heat from the heating coil 3.

  When the infrared energy from the cooking container 1 is very small, the sensitivity of the infrared sensor 4 can be increased by mirror-finishing the inside of the light guide means 10, and when the inner surface is painted in black or the like, disturbance light is emitted. Can be less affected.

  Further, the light guide means 10 is preferably extended to a position closer to the top plate 2 than the upper surface of the heating coil 3 as shown in FIG. This is because the cooling air for cooling the inverter that generates the induction magnetic field and the heating coil 3 does not easily enter the light guide means 10. This is because when the cooling air enters the light guiding unit 10, the cooling air may enter the light guiding unit 10 while being heated by the heating coil 3 or the like, and raise the temperature of the infrared sensor 4. This is because if the temperature of the infrared sensor 4 rises, the light receiving sensitivity changes, and therefore it is desirable for the infrared sensor 4 to be maintained at the same temperature. In order to reduce the influence of disturbance light, it is desirable that the light guide means 10 extends to a position close to the top plate 2. However, since the detection area of the infrared sensor 4 may be narrowed, in that case, it is necessary to design in a place where both are balanced.

(Embodiment 7)
Next, a seventh embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content of the invention described in the seventh embodiment is an induction heating apparatus in which the illuminance sensor is installed in the same light guiding means as the infrared sensor.

  As described in the sixth embodiment, the light guide unit 10 extends from the detection unit of the infrared sensor 4 to the vicinity of the top plate 2, and has a configuration in which disturbance light does not easily reach the detection unit of the infrared sensor 4. Since the illuminance sensor 6 is for measuring the illuminance around the detection part of the infrared sensor 4, the illuminance sensor 6 and the infrared sensor 4 can be measured more accurately by being adjacent to each other. Therefore, the illuminance sensor 6 can measure the illuminance more accurately by being installed in the same light guide means 10 as the infrared sensor 4.

(Embodiment 8)
Next, an eighth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the invention described in the eighth embodiment, when the illuminance detected by the illuminance sensor described in the first to seventh embodiments is darker than a predetermined value, the cooking container detection means determines that there is a cooking container. This is a heating device.

  As described in the first embodiment, the case of the eighth embodiment corresponds to STEP 4 in FIG. This is a state in which the infrared sensor 4 receives neither infrared energy from the cooking container 1 nor ambient energy of ambient light. Accordingly, the bottom of the cooking container 1 covers the detection area of the infrared sensor 4 and the infrared energy from the cooking container 1 can be received. The temperature detecting means 5 can accurately calculate the temperature from the energy received by the infrared sensor 4.

  However, even when the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, the infrared sensor 4 may not receive infrared energy because the illuminance around the cooking container 1 is β or less. It is thought that there is. In that case, since the amount of infrared energy that can be detected by the infrared sensor 4 is reduced as compared with the case where the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, the temperature may not be detected accurately. . Since these cannot be distinguished from each other, the control may be such that the user of the induction heating device is notified that the presence or absence of the cooking container 1 cannot be determined.

(Embodiment 9)
Next, a ninth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The invention described in the ninth embodiment is an induction heating apparatus in which a plurality of illuminance sensors are provided, one illuminance sensor is installed in the same light guide unit as the infrared sensor, and the other is installed outside the light guide unit. Is.

  As described in the eighth embodiment, when the illuminance detected by the illuminance sensor is darker than a predetermined value, it is understood that the energy of disturbance light has not reached the detection unit of the infrared sensor 4. However, the energy of ambient light around the cooking vessel 1 placed on the top plate 2 reaches the detection unit of the infrared sensor 4 because the bottom of the cooking vessel 1 covers the detection area of the infrared sensor 4. It is not possible to determine whether there is no ambient light energy around the cooking container 1 or not.

  In order to determine this, using a plurality of illuminance sensors, the illuminance sensor 6a measures the illuminance around the detection part of the infrared sensor 4 and the illuminance sensor 6b uses the illuminance around the cooking container 1 as shown in FIG. These situations can be determined by measuring

  The detection method of a cooking container when using several illumination intensity sensors is demonstrated using FIG.

  In STEP 1, the energy received by the illuminance sensor 6 a that measures the illuminance around the detection unit of the infrared sensor 4 is measured. The measured value is V1.

  In STEP2, the energy received by the illuminance sensor 6b that measures the illuminance around the cooking vessel 1 is measured. The measured value is V2.

  In STEP 3, the magnitude of V1 measured by the illuminance sensor 6a and the determination value α are compared. The determination value α will be described with reference to FIG. The infrared sensor 4 detects when the infrared sensor 4 is placed in an environment with a certain illuminance β with respect to the energy a detected by the infrared sensor 4 when the infrared sensor 4 is placed in a dark state and not receiving disturbance light energy. The illuminance is increased to a level at which the illuminance sensor 6 and the cooking device detection means 7 receiving the output can detect that a difference (b−a) has occurred between the energy b and the energy of the infrared sensor 4 becomes b. Α is set as a value obtained by adding a variation element and a margin to the illuminance β. When V1> α, since the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, the light around the cooking container 1 enters the detection area of the infrared sensor 4 as disturbance light, and the infrared sensor 4 It can be considered that the infrared sensor 4 is placed in such a state that light is received and the received light energy becomes high.

  In STEP4, the magnitude of V2 measured by the illuminance sensor 6b and the determination value γ are compared. The determination value γ will be described with reference to FIG. The difference (d) between the energy c received by the infrared sensor 4 when the infrared sensor 4 is in the dark state and the energy d received by the infrared sensor 4 when the infrared sensor 4 is placed in an environment with a certain illuminance. The illuminance is increased to a level at which occurrence of -c) can be detected, and γ is set as a value obtained by adding the variation element and the margin to the illuminance δ when the energy of the infrared sensor 4 becomes d. When V2> γ, there is sufficient illuminance around the cooking container 1, so if the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, It can be considered that the infrared sensor 4 is placed in a state where the light enters the detection area of the infrared sensor 4 as disturbance light, and the infrared sensor 4 receives the light to increase the received light energy.

  Since STEP5 satisfies the conditions of V1> α and V2 <γ, it can be seen that the surroundings are sufficiently darker than V2 <γ and that ambient light cannot enter from the surroundings. From V1> α, the infrared sensor 4 detects a larger value than when it is placed in a dark state. As a situation that can be such a condition, there is some shading object in the detection area of the illuminance sensor 6b that measures the illuminance around the cooking container 1, and the illuminance sensor 6b that the surrounding of the cooking container 1 is originally bright. In this state, the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, so that ambient light enters the detection part of the infrared sensor 4 and V1> α. It is possible that

  Alternatively, the surroundings are sufficiently darker than V2 <γ, but the cooking container 1 is at a high temperature that radiates infrared energy to a wavelength in the visible light range, and the energy from the cooking container 1 is measured with an illuminance sensor. It is conceivable that 6a is receiving light. Also in that case, since the heating control means 8 should normally control so that the cooking container 1 may not become such high temperature, it is an abnormal state.

  Alternatively, a failure state in which the bonding wire of the illuminance sensor 6b is disconnected and the illuminance sensor 6b cannot output can be considered.

  In any case, because it is a situation that cannot be normal, it is controlled to stop heating or suppress the amount of heating power as an abnormality, or an abnormality is notified by notifying the user of the induction heating device by an informing means. It is necessary to avoid the situation.

  In STEP6, the conditions are V1> α and V2> γ. Therefore, it can be seen that the surroundings are sufficiently brighter than V2> γ and that ambient light can enter from the surroundings. Since V1> α, the infrared sensor 4 detects a larger value than when it is placed in a dark state, so it is considered that light around the cooking vessel 1 enters as disturbance light and receives infrared energy. . That is, there is a possibility that the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, and there is a possibility that the S / N ratio deteriorates due to light other than infrared energy from the cooking container 1 and the temperature cannot be detected accurately. is there. Therefore, it is determined that there is no cooking container 1 in such a state, and control is performed so that heating of the cooking container 1 is stopped or the amount of heating power is suppressed.

  Since STEP7 is the same as STEP4, description is abbreviate | omitted.

  Since STEP8 is a condition of V1 <α, V2> γ, it can be seen that the surroundings are sufficiently brighter than V2> γ, and ambient light can enter from the surroundings. From V1 <α, it can be determined that the infrared sensor 4 is in a dark state. That is, although the ambient light may be received by the infrared sensor 4, the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, so the ambient light is blocked. Since the cooking container 1 is determined to be present because the infrared energy from 1 can be received, the temperature detection means 5 can accurately calculate the temperature from the energy received by the infrared sensor 4 even if the cooking container 1 is heated. . At this time, since the cooking container 1 is low temperature, it turns out that infrared energy is not radiated | emitted.

  Since STEP9 has the conditions of V1 <α and V2 <γ, it can be seen that the surroundings are sufficiently darker than V2 <γ and that ambient light cannot enter from the surroundings. From V1 <α, the infrared sensor 4 is the same as when it is placed in a dark state. That is, the infrared sensor 4 receives neither infrared energy from the cooking container 1 nor ambient light from the surroundings, but it is known that there is no disturbing light from the surroundings. The detection area may not be covered, and it cannot be determined that the cooking container 1 is present. Therefore, since the presence or absence of the cooking container 1 cannot be determined in such a state, the user of the induction heating apparatus is notified to that effect, or heating of the cooking container 1 is stopped or heating power is given priority to safety. Therefore, it is necessary to determine a design concept such as performing control so as to suppress this.

  In this way, the conventional infrared sensor 4 alone has a problem that the accurate temperature cannot be measured when ambient light enters, but the cooking container detection means 7 as in the present invention. In order to determine whether or not the cooking container 1 is present, and to determine whether or not an accurate temperature can be detected, the cooking container 1 excessively rises in temperature, causing deformation or breakage of the cooking container 1 or ignition of oil. Thus, it is possible to provide an induction heating apparatus that can avoid a dangerous situation such as the above, and to provide a benefit to the user.

(Embodiment 10)
Next, an embodiment 10 of the invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The invention described in the tenth embodiment is cooked when the illuminance sensor installed in the light guide means is darker than the predetermined value and the illuminance sensor installed outside the light guide means is brighter than the predetermined value. The container detection means is an induction heating apparatus that determines that there is a cooking container.

  As described in the ninth embodiment, the case of the tenth embodiment is the case of STEP 8 in FIG. This indicates that the periphery of the cooking container 1 is bright and the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, so that the periphery of the detection part of the infrared sensor 4 is dark. In this case, the infrared sensor 4 can receive the infrared energy from the cooking container 1 without being affected by disturbance light, and the temperature detecting means 5 can calculate the temperature without much error. The cooking vessel 1 can be heated without excessive temperature rise and becoming dangerous.

(Embodiment 11)
Next, an eleventh embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  In the invention described in the eleventh embodiment, when the illuminance sensor 6a is darker than the predetermined value and the illuminance sensor 6b is darker than the predetermined value, the notification means notifies that the presence or absence of the cooking container cannot be detected. This is a heating device.

  As described in the ninth embodiment, the case of the eleventh embodiment corresponds to STEP 9 in FIG. This indicates that the periphery of the cooking container 1 is dark and the periphery of the detection part of the infrared sensor 4 is also dark. However, it cannot be determined whether or not the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, and the cooking container detection means 7 cannot determine the presence or absence of the cooking container 1. If heating is started or continued in such a state, the cooking container 1 may become hot as the user does not intend in some cases, and the cooking container 1 may be in a dangerous state such as deformation or breakage of the cooking container 1 or ignition of oil. is there.

  Therefore, by telling the user to that effect by the notification means, it is urged to change the place where the cooking container 1 is placed, and it is possible to lead to a state where heating can be performed safely. By doing so, it is possible to avoid the situation where heating is not possible.

(Embodiment 12)
Next, an embodiment 12 of the invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The invention described in the twelfth embodiment is an induction heating device in which the cooking container detection means detects the cooking container at least once before the heating control means starts heating.

  As described in the first embodiment, when detecting the temperature using the infrared sensor 4, it is necessary to eliminate the influence of disturbance light and to receive the infrared energy from the object. When not in such a situation, the S / N ratio of the energy received by the infrared sensor 4 is poor, and the temperature calculated by the temperature detecting means 5 includes many errors. That is, the cooking container 1 may be at a high temperature that is not intended by the user.

  In order to avoid such a situation, safety can be ensured by operating the cooking container detection means 7 at least once before starting heating and determining the presence or absence of the cooking container 1.

(Embodiment 13)
Next, an embodiment 13 of the invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content described in the thirteenth embodiment is that, when the heating control means is heating the cooking container, if the cooking container detection means determines that there is no cooking container, the heating control means stops heating or the amount of heating power This is an induction heating apparatus that provides a time difference until the suppression is suppressed.

  When cooking container 1 is heated during heating, the energy of ambient light reaches infrared sensor 4 and cooking container detection means 7 may determine that cooking container 1 is not present. When the cooking container 1 does not cover the detection area of the infrared sensor 4, accurate temperature measurement is difficult, and thus control is performed to stop heating or suppress the amount of heating power.

  However, when the cooking container 1 is being heated, there is a high possibility that the bottom of the cooking container 1 is returned to the state of covering the detection area of the infrared sensor 4, so that the cooking container detection means 7 does not have the cooking container 1. Even if it is determined, if the heating is immediately stopped or the amount of heating power is suppressed, the operation becomes unintended by the user and the usability is reduced.

  Therefore, even if the cooking container detection means 7 determines that the cooking container 1 is not present, heating is not stopped immediately or the amount of heating power is not suppressed, and the cooking container 1 really covers the detection area of the infrared sensor 4 with a time difference. It is possible to prevent a decrease in usability by determining whether or not the heating is continued in a state where the heating is not performed and then stopping the heating or suppressing the heating power amount.

  In addition, when performing cooking, if the cooking container 1 is far away from the heating coil 3, the safety function of the induction heating device itself may work, and heating may be stopped. This safety function detects that the cooking container 1 is largely separated from the heating coil 3 from the change in magnetic coupling including the cooking container 1 and the heating coil 3, and determines that there is no cooking container 1 if it is separated. This is a function to stop heating.

  In the case of the induction heating device that detects the temperature with the infrared sensor 4, even when it is determined that the cooking container 1 is present by detecting the presence or absence of the cooking container 1 from the above magnetic coupling, the bottom of the cooking container 1 is the infrared sensor 4. When the detection area is not covered, the temperature measurement error becomes large. Therefore, in order to avoid such a situation, the cooking container detection means 7 is separately provided to ensure safety.

(Embodiment 14)
Next, a fourteenth embodiment of the present invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content of the invention described in the fourteenth embodiment is that the cooking container detection means is an induction heating device that detects the cooking container at least once within a time difference.

  As described in the twelfth embodiment, when the cooking container 1 is heated, the cooking container detection means 7 determines that the cooking container 1 is not present, and a time difference is provided until the heating is stopped or the heating power amount is suppressed. And before actually stopping the heating or suppressing the heating power amount, the presence or absence of the cooking container 1 is determined at least once, and the heating is stopped or the heating power amount is suppressed only when the cooking container 1 is not really present. A decrease in usability can be avoided.

(Embodiment 15)
Next, an embodiment 15 of the invention will be described. Description of the same parts as those in the first embodiment will be omitted, and only differences will be described.

  The content of the invention described in the fifteenth embodiment is an induction heating apparatus in which a portion obtained by dividing a heating coil in the radial direction is provided, and an infrared sensor is disposed in a gap portion of the coil.

  As shown in FIG. 9, the temperature distribution when the cooking container 1 is heated by induction has a temperature peak at the central portion of the heating coil 3, and the central portion of the cooking container 1 has a low temperature distribution.

  In order to provide a safe induction heating device that does not ignite oil even when oil is dropped on the maximum temperature portion of the cooking container 1 when the temperature of the cooking container 1 rises without the user's intention, the cooking container 1 It is necessary to control so that the maximum temperature part of 1 is below the ignition point of oil.

  For that purpose, it is better to arrange the infrared sensor 4 near the center of the heating coil 3 than at the center. Therefore, as shown in FIG. 10, the heating coil 3 can be provided at a location where the heating coil 3 is divided in the radial direction, and by placing the infrared sensor 4 in the gap, the temperature close to the maximum temperature of the cooking vessel 1 can be measured. It is possible to realize a safe and secure induction heating device that does not cause ignition.

  As described above, in the induction heating device according to the present invention, when the presence or absence of a cooking container, which was a problem when performing temperature detection with an infrared sensor, is detected, and the cooking container is sure and the temperature can be accurately measured By using an induction heating device that only keeps heating, the cooking vessel is controlled to a temperature at which the cooking vessel is not deformed or damaged, or oil ignition, etc., so that safety is improved and an easy-to-use induction heating device is realized. be able to.

Schematic block diagram of the induction heating apparatus in Embodiment 1 of the present invention Determination flowchart of cooking container detection means in Embodiment 1 of the present invention The figure showing the design of the judgment value in Embodiment 1 of this invention Diagram showing infrared energy and visible light wavelength Schematic block diagram of the induction heating apparatus in Embodiment 4 of this invention Schematic configuration diagram of an induction heating device in Embodiment 9 of the present invention Determination flowchart of cooking container detection means in Embodiment 9 of the present invention The figure showing the design of the judgment value in Embodiment 9 of this invention The figure showing the temperature distribution of the cooking container when heated with the induction heating device Schematic block diagram of the induction heating apparatus in Embodiment 15 of this invention Schematic configuration diagram of a conventional induction heating device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooking container 2 Top plate 3 Heating coil 4 Infrared sensor 5 Temperature detection means 6 Illuminance sensor 7 Cooking container detection means 8 Heating control means 9 Notification means 10 Light guide means

Claims (15)

A cooking container for heating food, a top plate on which the cooking container is placed, a heating coil for generating an induction magnetic field to heat the cooking container, and infrared rays radiated from the cooking container through the top plate An infrared sensor for detecting the temperature, a temperature detecting means for converting the temperature of the cooking container from the energy received by the infrared sensor, an illuminance sensor for detecting the ambient illuminance of the detection part of the infrared sensor, and the illuminance sensor receiving light Cooking container detection means for determining the presence / absence of the cooking container from energy, and the heating power amount of the cooking container by controlling the high-frequency current of the heating coil based on the detection result of the cooking container detection means and the temperature information of the temperature detection means And when the cooking container is not detected by the cooking container detection means, the heating control means Induction heating device for controlling to suppress stop or heating power amount of heating of the cooking container. The induction heating apparatus according to claim 1, wherein the sensitivity wavelength range of the illuminance sensor is limited to the visible light range. The induction heating device according to claim 1 or 2, wherein a sensitivity wavelength region of the infrared sensor does not include a visible light region. The induction heating device according to claim 1, wherein the optical axes of the infrared sensor and the illuminance sensor are in the same direction. A notification means is provided, and when the cooking container detection means determines that there is no cooking container, or when it cannot be determined whether or not there is a cooking container, the notification means notifies the user of the induction heating device to that effect. The induction heating apparatus of any one of 1-4. The induction heating apparatus according to claim 1, wherein a light guide means for guiding infrared rays from the cooking container is provided between the top plate and the infrared sensor. The induction heating apparatus according to claim 6, wherein the illuminance sensor is installed in the same light guiding means as the infrared sensor. The induction heating device according to any one of claims 1 to 7, wherein when the illuminance detected by the illuminance sensor is darker than a predetermined value, the cooking container detection means determines that there is a cooking container. The induction heating apparatus according to claim 5 or 6, wherein a plurality of illuminance sensors are provided, one illuminance sensor is installed in the same light guide means as the infrared sensor, and the other is installed outside the light guide means. When the illuminance sensor installed in the light guide means is darker than the predetermined value and the illuminance sensor installed outside the light guide means is brighter than the predetermined value, the cooking container detection means determines that there is a cooking container. The induction heating apparatus according to any one of claims 1 to 9. When the illuminance sensor installed in the light guide means is darker than the predetermined value and the illuminance sensor installed outside the light guide means is darker than the predetermined value, the notification means cannot detect the presence or absence of the cooking container. The induction heating device according to claim 10, which is notified. The induction heating apparatus according to any one of claims 1 to 11, wherein the cooking container detection means detects the cooking container at least once before the heating control means starts heating. 2. When the heating control means is heating the cooking container and the cooking container detection means determines that there is no cooking container, the heating control means provides a time difference until the heating is stopped or the heating power amount is suppressed. The induction heating device according to any one of -12. The induction heating apparatus according to claim 13, wherein the cooking container detection means detects the cooking container at least once within a time difference. The induction heating apparatus according to claim 1, wherein a portion obtained by dividing the heating coil in the radial direction is provided, and an infrared sensor is disposed in a gap portion of the coil.