JP2008117783A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect the temperature of a pan placed on a top plate in an induction heating cooker. <P>SOLUTION: This induction heating cooker has a heating coil 3 heating the pan 1, the top plate 2 placing the pan above the heating coil 3, an infrared ray detecting means 5 placed under the top plate 2 and detecting infrared ray radiated from a bottom surface of the pan 1, a temperature detecting means 9 detecting the pan bottom surface temperature from output of the infrared ray detecting means, a control means 10 controlling electric power supplied to the heating coil 3 in response to output of the temperature detecting means 9, and a shading means 6 positioned under the top plate 2. The temperature of the pan can be controlled by accurately detecting the temperature of the pan by preventing incidence of infrared ray to the infrared ray detecting means other than that from the pan by the shading means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an induction heating cooker that heats a pan placed on a top plate by induction heating to cook food in the pan.

  In an induction heating cooker that heats an object to be heated such as a pot, as a method of detecting the temperature of the pot of the object to be heated, there is a method of detecting the temperature with a thermistor through a top plate on which the pot is placed. In addition, there is an apparatus for detecting the temperature by detecting the infrared ray radiated from the side surface of the pan with an infrared sensor behind the top surface of the top plate. Furthermore, an infrared sensor is arranged on the lower surface of the top plate to detect infrared rays from the pan through the top plate (for example, see Patent Document 1).

  In the induction heating cooker having the conventional configuration shown in FIG. 6, the temperature of the pan 1 is received by the thermistor 50 through the top plate 2 to detect the temperature, and the pan according to the temperature detection output of the thermistor 50. The electric power supplied to the heating coil 3 for induction heating 1 is controlled by the control means 51 for cooking. Here, the top plate 2 made of ceramics has a low heat transfer coefficient, and due to a delay in the thermal response of the top plate 2, an actual pan temperature and error occur, and the temperature of the object to be heated cannot be detected with high accuracy. And in the case of a pan with a warped bottom, it is even more susceptible.

In addition, the infrared sensor 53 behind the top plate 2 is affected by ambient light such as sunlight or illumination, and cannot accurately detect temperature. Furthermore, if the infrared sensor is simply disposed on the lower surface of the top plate 2, it may be affected when there is ambient light incident from an oblique direction.
Japanese Patent Laid-Open No. 03-184295

  In view of the above-described problems of the conventional technology, the problem to be solved by the present invention is to provide an induction heating cooker that can accurately detect the temperature of a pan while avoiding the influence of ambient light.

  In order to solve the above-described problems, the present invention provides a heating coil for induction heating of a pan, a top plate for placing the pan above the heating coil, and an infrared ray placed under the top plate and emitted from the bottom of the pan. Infrared detecting means for detecting the temperature, temperature detecting means for detecting the temperature of the bottom of the pan from the output of the infrared detecting means, control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detecting means, and the ceiling An induction heating cooker located at the bottom of the plate and equipped with a light-shielding means configured to prevent infrared rays from other than the pan from entering the infrared detection means, accurately detecting the temperature of the pan without being affected by ambient light In addition, this enables accurate cooking control.

  The induction heating cooker of the present invention can accurately detect the temperature at the bottom of the pan without being affected by disturbance light, and is stable by avoiding the influence even when disturbance light is incident on a warped pan or the like. Thus, the temperature can be detected with good responsiveness, and the temperature can be controlled according to the temperature of the pan bottom.

  1st invention is a heating coil which induction-heats a pan, the top plate which mounts a pan in the upper part of the heating coil, and infrared detection which detects infrared rays which are put under the top plate and are emitted from the bottom of the pan Means, temperature detecting means for detecting the temperature of the bottom of the pan from the output of the infrared detecting means, control means for controlling the power supplied to the heating coil according to the output of the temperature detecting means, and a lower part of the top plate. An induction heating cooker provided with a light shielding means provided so that infrared rays from other than the pan are not incident on the infrared detection means, and disturbing light incident on the infrared detection means from other than the pan is blocked by the light shielding means. The infrared rays emitted from the bottom of the pan can be accurately detected and the temperature of the pan can be detected accurately and stably.

  A second invention is an induction heating cooker in which the light shielding means of the first invention is integrated with a holding means to which the heating coil is fixed, and the light shielding means is highly accurate with an infrared sensor which is an infrared detection means. The position can be kept, and only the infrared rays of the disturbance can be blocked without blocking the field of view of the infrared sensor, so that the temperature of the pan can be detected stably and accurately.

  3rd invention is the induction heating cooking appliance which provided the light-shielding means of 1st invention so that the said top plate other than the upper part of an infrared detection means might be covered, and the infrared rays of the disturbance which wraps around and enters an infrared detection means The effect can be eliminated and the temperature of the pan can be detected accurately and stably.

  4th invention is the heating coil which heats a pan, the top plate which mounts a pan on the said heating coil, and the infrared detection means which detects the infrared rays which are set | placed under the said top plate and are radiated | emitted from the said pan bottom face And a temperature detection means for detecting the bottom surface temperature of the pan from the output of the infrared detection means, and a control means for controlling the power supplied to the heating coil according to the output of the temperature detection means, wherein the top plate is removed from the pan. In the induction heating cooker formed by printing on the back of the top plate, for example, a portion having a high reflectivity other than the range through which the infrared rays pass when entering the infrared detection means, the top plate reflects inside the top plate The infrared rays of the disturbance that propagates can be effectively blocked, and the temperature of the pan can be detected accurately.

  5th invention is a heating coil which induction-heats a pan, the top plate which mounts a pan on the said heating coil, and the infrared detection which detects the infrared rays which are put under the said top plate and are radiated | emitted from the said pan bottom face Means, temperature detection means for detecting the pan bottom temperature from the output of the infrared detection means, and control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detection means, the top plate is at least An induction heating cooker with a portion with high reflectivity outside the range of the smallest pan diameter that can be cooked, such as printing on the surface of the top plate. Infrared rays of disturbance are incident from the top plate outside the range where the pan is located. Without this, the temperature of the pan can be detected accurately.

  A sixth aspect of the present invention is the method according to any one of the first to fifth aspects, wherein the heating coil, the infrared detection unit, the temperature detection unit, and the like are provided in a housing, and the inner surface of the housing has a low reflectance. The induction heating cooker formed in the above can reduce the reflection of infrared rays on the inner surface of the housing and can detect the temperature of the pan accurately and stably.

  The seventh invention is a heating coil for induction heating of a pan, a top plate for placing the pan on the heating coil, and an infrared detection for detecting infrared rays placed under the top plate and emitted from the bottom surface of the pan. Means, temperature detection means for detecting the temperature of the bottom of the pan from the output of the infrared detection means, and control means for controlling the power supplied to the heating coil according to the output of the temperature detection means, Induction heating cooker configured to stop heating with the output from the control means when infrared rays from other than the pot enter the infrared detection means and a temperature change more than a predetermined value occurs in the temperature detection means. When infrared rays are incident, the malfunction of the device is prevented.

  The eighth invention is a heating coil for induction heating of a pan, a top plate for placing the pan on the heating coil, and infrared detection for detecting infrared rays placed under the top plate and emitted from the bottom of the pan. Means, temperature detection means for detecting the temperature of the bottom of the pan from the output of the infrared detection means, and control means for controlling the power supplied to the heating coil according to the output of the temperature detection means, When the infrared rays from other than the pan enter the infrared detection means and the temperature detection means causes a temperature change more than a predetermined level, the induction heating cooker is configured not to change the control for a certain period of time. More avoidable.

  A ninth invention is a heating coil for induction heating a pan, a top plate on which the pan is placed above the heating coil, and an infrared detector that detects infrared rays placed under the top plate and emitted from the bottom of the pan. Means, temperature detecting means for detecting the pan bottom temperature from the output of the infrared detecting means, and control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detecting means, the control means being a pan Induction heating cooker configured to increase power for a certain period of time when infrared rays from outside enter the infrared detection means and the temperature detection means undergoes a temperature change above a predetermined level. It is possible to avoid the influence of the incident.

  A tenth aspect of the invention is an induction heating cooker according to any one of the seventh to ninth aspects of the invention, wherein the temperature detecting means notifies the temperature detecting means when the temperature change occurs by a notifying means. When infrared rays from other than the above are incident, not only can the malfunction of the device be prevented, but also the user can be notified.

  An eleventh aspect of the invention is the induction heating cooker according to any one of the seventh to tenth aspects of the invention, wherein when a temperature change of a predetermined value or more occurs in the temperature detection means, the display means of the operation unit displays the change. When infrared rays from other than the pan enter, not only prevents malfunction of the device, but also makes it easy for the user to understand and continuously inform the user.

  Since the induction heating cooker of the present invention can achieve the object of the present invention by using the configurations of the first to eleventh inventions as the main part of the embodiment, each of the claims corresponding to each claim will be described below. Details of the embodiment will be described with reference to the drawings to explain the embodiment. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram showing an induction heating cooker according to Embodiment 1 of the present invention. The induction heating cooker in the present embodiment includes a heating coil 3 that induction-heats a pan 1 in which an object to be heated is placed and cooks, a top plate 2 on which the pan 1 is placed above the heating coil 3, and a top plate In response to the output of the infrared detecting means 5 for detecting the infrared rays placed under the pan 2 and radiating from the bottom of the pan, the temperature detecting means 9 for detecting the temperature of the bottom of the pan from the output of the infrared detecting means 5, and the output of the temperature detecting means 9 The control means 10 for controlling the high frequency current that is the power supplied to the heating coil 3 and the lower part under the top plate 2 are provided so that infrared rays from other than the pan 1 do not enter the infrared detection means 5. An annular light shielding means 6 is provided. In the figure, reference numeral 4 denotes an inverter that supplies a high-frequency current to the heating coil 3 and heats the pan 1 by electromagnetic induction, 7 is a reflecting means, 8 is an amplifying means, and 11 is a casing.

  In the above embodiment, when a power supply (not shown) is turned on and a predetermined temperature is set with the operation switch, electric power is supplied from the inverter 4 to the heating coil 3 under the control of the control means 10. When electric power is supplied to the heating coil 3, an induction magnetic field is generated in the heating coil 3, and the pan 1 on the top plate 2 is induction-heated. Due to this induction heating, the temperature of the pan 1 rises and the object to be heated in the pan 1 is cooked. Here, the operation of the infrared detecting means 5 will be described. When the temperature of the pan 1 rises, infrared rays corresponding to the temperature are emitted from the pan 1.

  Since the glass ceramics used for the top plate 2 can efficiently transmit infrared rays having a wavelength range of 2.5 μm or less, the infrared detection means 5 is, for example, a photodiode that can detect wavelengths of 2.5 μm or less. The infrared ray of this wavelength range which passed through the top plate 2 is incident on the photodiode. Further, the reflecting means 7 is formed in a cylindrical shape, and the inner surface is formed in a mirror surface having a high reflectance so that more infrared rays can be collected and made incident on the photodiode disposed in the center of the bottom. .

  In addition to the infrared rays from the pan 1, ambient light such as sunlight or illumination may be incident. Moreover, when the bottom of the pan 1 warps, it becomes more susceptible to disturbance light. For this reason, the infrared rays incident on the infrared detection means 5 from other than the pan 1 are blocked by the light shielding means 6. With these configurations, in the present embodiment, only the infrared light from the pan 1 is incident on the infrared detection means 5, and the diode current matched with the amount of infrared light is converted from current to voltage by the amplification means 8 and amplified. This information is input to the temperature detection means 9, and the temperature of the pan can be detected accurately. Thereby, the inverter 4 is controlled from the control means 10 to accurately control the pan 1 so as to reach a predetermined temperature, and the object to be heated can be cooked deliciously.

  Further, in the present embodiment, the light shielding means 6 is integrated with the coil substrate 3a as a holding means made of resin or the like for holding the heating coil 3, so that the positions of the light detecting means 6 and the infrared detecting means 5 and the reflecting means 7 are the same. Since the accuracy can be maintained, only the disturbance infrared rays can be blocked without blocking the field of view of the infrared detection means 5, and the temperature of the pan can be detected stably and accurately.

  Further, in the present embodiment, if the light shielding means 6 is provided so as to cover the lower surface of the top surface 2 other than the upper part of the infrared detecting means 5, it is possible to eliminate the influence of disturbance infrared rays that enter and enter. It is more stable and can accurately detect the temperature of the pan.

(Embodiment 2)
FIG. 2 is a block diagram showing the configuration of the induction heating cooker according to the second embodiment of the present invention. The induction heating cooker according to the present embodiment is different from the light shielding unit of the invention according to the first embodiment only in that the function of the light shielding unit is added to the top plate, and has the same other configurations and operational effects. Parts are denoted by the same reference numerals, detailed description thereof is omitted, and different points will be mainly described.

  As with the top plate shown in FIG. 1, the top plate 12 is for placing the pan 1 on the top of the heating coil 3, and other than the range through which the infrared rays from the pan 1 pass when entering the infrared detection means 5. A portion 12a having a high reflectivity is formed so as to block the incidence of disturbance light. That is, the top plate 12 is printed with high reflectivity on the back surface of the top plate 12 outside the visual field range of the infrared detecting means 5 to form a highly reflective portion 12a. The printing material is, for example, a paste with a high gloss of silver.

  The top plate 12 has a mirror surface on the top surface, and has a light reflectance of 90% or more. For this reason, the infrared rays of disturbances such as the sun and illumination that are incident at an angle with no angle are reflected by the highly reflective portion 12 a on the back surface of the top plate 11, and therefore hardly enter the infrared detection means 5. With these configurations, in the present embodiment, only the infrared light from the pan 1 is incident on the infrared detection means 5, and the diode current matched with the amount of infrared light is converted from current to voltage by the amplification means 8 and amplified. This information is input to the temperature detection means 9, and the temperature of the pan can be detected accurately. Thereby, the inverter 4 is controlled from the control means 10, and the pan 1 is accurately controlled so as to reach a predetermined temperature, so that the object to be heated can be cooked deliciously.

  Moreover, in this Embodiment, it is good also as a structure given to the surface of the top plate 12 outside the range of the pan diameter of the minimum shape which can be cooked, and the part 12a printed with high reflectance silver. That is, even when a pan having a minimum diameter is placed on the top plate, the infrared rays of disturbance are reflected on the surface of the top plate. As a result, the reflection on the back surface of the top plate and the reflection on the pan are not repeatedly incident on the infrared detecting means 5. With this configuration, it is possible to provide an induction heating cooker that can accurately detect the temperature of the pan without causing disturbance infrared rays to enter.

  Further, in the present embodiment, by using a material having a low reflectance on the inner surface of the housing 11 or by painting with a low reflectance, disturbance infrared rays partially reflected from the bottom surface of the housing are also generated. Can be made an induction heating cooker that can detect the temperature of the pan more accurately.

(Embodiment 3)
FIG. 3 is a diagram showing a control mode corresponding to the output of the temperature detection means 9 in the induction heating cooker according to the third embodiment of the present invention. The induction heating cooker in the present embodiment is different from the invention of the first embodiment only in the control method of the control means 10, and other parts having the same configuration and operational effects are denoted by the same reference numerals using FIG. 1. Detailed description will be omitted, and different points will be mainly described.

  The control means 10 is placed under the top plate 2 and supplied to the heating coil 3 according to the output of the temperature detecting means 9 for detecting the temperature of the bottom of the pan from the output of the infrared detecting means 5 for detecting the infrared rays emitted from the bottom of the pan. A configuration for stopping the operation of the heating coil 3 when infrared rays from other than the pan 1 are incident on the infrared detection means 5 and a temperature change of a predetermined value or more occurs in the temperature detection means 8. In other words, the malfunction of the device is prevented when the power supply is stopped for a certain period of time and infrared rays from other than the pan are incident.

  In the said embodiment, the control means 10 controls the electric power supplied to the heating coil 3, as shown in FIG. 3, when the infrared rays from other than a pan enter. That is, the vertical axis indicates temperature, power, and output voltage, and the horizontal axis indicates time, and the temperature change in the pot 1 and the pot water, the change in the output voltage of the temperature detection means 9, and the heating coil 3 are supplied. As shown in FIG. 3, the infrared detection means 5 detects infrared rays corresponding to the temperature of the pot bottom, and the temperature detection means 9 sets the temperature of the pot bottom. Here, when the pan 1 is warped in the bottom, or when a gap is generated between the pan 1 and the top plate 2 due to a foreign object being sandwiched, and the infrared ray of disturbance is suddenly incident, the infrared detecting means 5 that detects this. The output of the temperature detecting means 9 due to drifts as in mode 2 and remains at the same temperature for a certain time. When this abnormal temperature drift continues for a certain period of time, the control means 10 that has taken in this stops the supply of power to the heating coil 3 for a certain period of time and stops the heating. With this configuration, it is possible to realize an induction heating cooker that can prevent malfunction of the device and perform stable temperature control when infrared rays from other than the pan enter.

  In the above embodiment, in order to prevent malfunction of the device when infrared rays from other than the pan enter and to enable stable temperature control, the output of the temperature detecting means 9 changes suddenly, and the abnormal temperature The control unit 10 is configured to stop the heating by the heating coil 3 when the drift continues for a certain time. However, the same effect as in the present embodiment can be expected even in the following control mode. .

  That is, for example, in cooking such as automatic water heating, since the pan bottom temperature rises only to a maximum of about 100 ° C. even if heating is continued, there is little risk of continuing heating, so as shown in FIG. When the infrared rays suddenly entered and the output of the temperature detecting means 9 by the infrared detecting means 5 that detected this was drifted as in the mode 2 and this abnormal temperature drift continued for a certain period of time, it was captured. The control means 10 performs control that does not change the supply of power to the heating coil 3 for a certain period of time. As a result, the temperature of the pan rises after a certain period of time, and the situation is not affected by disturbance as in mode 3 of FIG. Thereby, the induction heating cooking appliance which can avoid that cooking is complete | finished in the middle and can perform stable temperature control is realizable.

  Further, for example, during cooking such as automatic water heating, since the pan bottom temperature only rises to about 100 ° C. at the maximum even if heating is continued, there is little risk of continuing heating, as shown in FIG. When the infrared rays from other than the pan enter the infrared detection means 5 and the temperature detection means 9 undergoes a temperature change more than a predetermined value, the control means 10 that has taken in the power for a certain period of time as in mode 4 Control to increase. By this structure, the induction heating cooking appliance which can avoid the influence which the infrared rays from other than a pan entered early and can perform stable temperature control is realizable.

    In each of the above-described embodiments, when a temperature change of a predetermined value or more occurs in the temperature detection means 9, the notification means notifies the user, and similarly, the temperature detection means 9 has a predetermined value or more. When the temperature change occurs, if the display means of the operation unit is used, the cooking status of the induction heating cooker can be easily understood and continuously notified to the user.

  As described above, the induction heating cooker of the present invention can accurately detect the temperature of the pan bottom without being affected by ambient light, and can accurately perform temperature control in accordance with the temperature of the pan bottom. It can be applied to a container and its control method.

The block diagram which shows the induction heating cooking appliance in Embodiment 1 of this invention The block diagram which shows the induction heating cooking appliance in Embodiment 2 of this invention The figure which shows the control form with the induction heating cooking appliance in Embodiment 3 of this invention. The figure which shows the other example of the control form with the induction heating cooking appliance in the same Embodiment 3. The figure which shows the other example of the control form with the induction heating cooking appliance in the same Embodiment 3. The block diagram which shows the induction heating cooking appliance in a prior art example

Explanation of symbols

1 Pan 2, 12 Top plate 3 Heating coil 3a Coil substrate (holding means)
5 Infrared detecting means 6 Shading means 9 Temperature detecting means 10 Control means 12a High reflectance portion

Claims (11)

A heating coil for inductively heating the pan; a top plate on which the pan is placed above the heating coil; an infrared detection means for detecting infrared rays placed under the top plate and emitted from the bottom of the pan; and the infrared detection Temperature detecting means for detecting the bottom surface temperature of the pan from the output of the means, control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detecting means, and the infrared detecting means located at the lower part of the top plate An induction heating cooker provided with light-shielding means provided so that infrared rays from other than the pan do not enter. The induction heating cooker according to claim 1, wherein the light shielding means is configured integrally with a holding means for fixing the heating coil. The induction heating cooker according to claim 1, wherein the light shielding means is configured to cover the top plate other than the upper part of the infrared detecting means. A heating coil for inductively heating the pan; a top plate on which the pan is placed above the heating coil; an infrared detection means for detecting infrared rays placed under the top plate and emitted from the bottom of the pan; and the infrared detection Temperature detection means for detecting the bottom surface temperature of the pan from the output of the means, and control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detection means, the infrared light from the pan is the infrared An induction heating cooker in which a portion having a high reflectance is formed outside a range that passes when entering the detection means. A heating coil for inductively heating the pan; a top plate on which the pan is placed above the heating coil; an infrared detection means for detecting infrared rays placed under the top plate and emitted from the bottom of the pan; and the infrared detection Temperature detection means for detecting the bottom surface temperature of the pan from the output of the means, and control means for controlling the power supplied to the heating coil according to the output of the temperature detection means, the top plate is at least a minimum shape that can be cooked An induction heating cooker that has a highly reflective part outside the pot diameter range. The housing according to any one of claims 1 to 5, wherein a housing having the heating coil, infrared detecting means, temperature detecting means, etc. is provided, and the inner surface of the housing is formed on a surface having a low light reflectance. Induction heating cooker. A heating coil for inductively heating the pan; a top plate on which the pan is placed above the heating coil; an infrared detection means for detecting infrared rays placed under the top plate and emitted from the bottom of the pan; and the infrared detection Temperature detecting means for detecting the temperature at the bottom of the pan from the output of the means, and control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detecting means, wherein the control means emits infrared rays from other than the pan in the infrared An induction heating cooker configured to stop the operation of the heating coil when a temperature change exceeding a predetermined level occurs in the temperature detecting means when entering the detecting means. A heating coil for inductively heating the pan; a top plate on which the pan is placed above the heating coil; an infrared detection means for detecting infrared rays placed under the top plate and emitted from the bottom of the pan; and the infrared detection Temperature detecting means for detecting the temperature at the bottom of the pan from the output of the means, and control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detecting means, the control means receiving infrared rays from other than the pot An induction heating cooker having a configuration in which the control is not changed for a certain period of time when a temperature change of a predetermined level or more occurs in the temperature detection means when entering the infrared detection means. A heating coil for inductively heating the pan; a top plate on which the pan is placed above the heating coil; an infrared detection means for detecting infrared rays placed under the top plate and emitted from the bottom of the pan; and the infrared detection Temperature detecting means for detecting the temperature at the bottom of the pan from the output of the means, and control means for controlling the power supplied to the heating coil in accordance with the output of the temperature detecting means, the control means receiving infrared rays from other than the pot An induction heating cooker configured to increase power for a certain period of time when a temperature change of a predetermined value or more occurs in the temperature detection means after entering the infrared detection means. The induction heating cooker according to any one of claims 7 to 9, wherein the temperature detecting means is configured to notify the notifying means when a predetermined temperature change or more occurs. The induction heating cooker according to any one of claims 7 to 10, wherein the temperature detection means is configured to display the temperature detection means with a display means of an operation unit when a predetermined temperature change or more occurs.

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