JP5274513B2 - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooking device that maintains detection accuracy of temperature detection means which detects a temperature by receiving infrared rays emitted from a cooking vessel even though visible lights are reflected for preventing an inner component such as a heating coil from being seen from above an infrared sensor. <P>SOLUTION: The induction heating cooking device comprises a top plate 2 on which a cooking vessel 3 is placed, a heating coil 4 for inductively heating the cooking vessel 3, an infrared sensor 5 for receiving infrared rays emitted from the cooking vessel 3 and transmitted through the top plate 2, temperature detection means 8a for detecting a temperature of the cooking vessel 3 based on an amount of the infrared rays received by the infrared sensor 5, control means 8 for controlling supply power to the heating coil 4 based on the temperature detected by the temperature detection means 8a, a reflection layer 7 with a reflective material being coated on at least one surface of the top plate 2 for reflecting visible lights and infrared rays, and an infrared transmission region 7b provided at a location facing the infrared sensor 5 on the reflection layer 7, which has higher infrared transmissivity compared with another region. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an induction heating cooker, and in particular, detects infrared rays radiated from a cooking vessel with an infrared sensor, obtains the temperature of the cooking vessel based on the amount of infrared rays, and performs temperature control during cooking. .

As a conventional technique, an induction heating cooker having a glass top plate for an electromagnetic cooker that has an infrared transmitting portion that is transparent to infrared rays at the portion facing the infrared sensor and the other portion is covered with an opaque layer is proposed. (For example, refer to Patent Document 1).
Here, the induction heating cooker is a cooker in which a heating coil is disposed below the top plate on which the cooking container is placed, and a high-frequency current is passed through the heating coil to heat an object to be heated in the cooking container by electromagnetic induction. It is.

Japanese Patent Laid-Open No. 10-284238 (Claim 1, FIG. 1)

  In the glass top plate for an electromagnetic cooker of Patent Document 1, when a cooking container is not placed on the glass top plate, internal parts such as a heating coil are visible from the window (infrared transmitting portion), so that the appearance is poor. There was a problem.

  The present invention has been made to solve the above problems, and even if visible light is shielded so that internal parts such as a heating coil cannot be seen from the upper part (infrared transmitting part) of the infrared sensor, It aims at providing the induction heating cooking appliance which can maintain the detection accuracy of the temperature detection means which receives the infrared rays which a cooking vessel radiates | emits, and detects temperature.

The induction heating cooker according to the present invention includes a top plate on which the cooking container is placed and transmits infrared rays, a heating coil that is provided below the top plate and induction-heats the cooking container, and cooking on the top plate An infrared sensor that is provided below the container placement area and receives infrared rays radiated from the cooking vessel and transmitted through the top plate, temperature detection means for detecting the temperature of the cooking vessel based on the amount of infrared rays received by the infrared sensor, and temperature detection Control means for controlling the power supplied to the heating coil based on the temperature detected by the means, visible light incident from above the top plate , formed by attaching a reflective material to at least one of the back surface and the front surface of the top plate; a reflective layer for reflecting infrared radiation, an infrared transmission region provided in a position facing the infrared sensor in the reflective layer For example, infrared transmission region, reflective material is coated thinly than in a region other than the infrared transmission region of the top plate, printed or bonded, or reflective material dots or sparsely coated, printed or glued have infrared transmission infrared transmittance is not high as compared with a region other than the region.

  In the present invention, a reflective material is formed on at least one of the back surface and the front surface of the top plate, and includes a reflective layer that reflects visible light and infrared light. By making it an infrared transmission region with higher infrared transmittance than the region, the inside of the induction heating cooker is made invisible, and infrared radiation emitted from the bottom of the cooking container is received by the infrared sensor, and from other than that The generated infrared rays can be cut. As a result, it is possible to maintain the accuracy of temperature detection for the cooking container without deteriorating the appearance of the induction heating cooker.

It is a block diagram which shows the induction heating cooking appliance which concerns on embodiment of this invention. It is a figure which shows the infrared rays transmission area | region which concerns on embodiment of this invention. It is a figure which shows the infrared rays transmission area | region which concerns on embodiment of this invention. It is a figure which shows the infrared rays transmission area | region which concerns on embodiment of this invention. (A) is a figure which shows the infrared transmission area | region which concerns on embodiment of this invention, (b) is sectional drawing which shows this infrared transmission area | region in detail.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an induction heating cooker according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram showing induction heating cooker 10 according to the present embodiment.
The induction heating cooker 10 according to the present embodiment is provided inside the casing 1 and is provided inside the casing 1 with a heating coil 4 that induction-heats the cooking container 3 in which an object to be heated is placed. An inverter 9 that supplies a high-frequency current to the coil 4 and a top plate 2 that is provided above the heating coil 4 and on which the cooking vessel 3 is placed are provided.

Further, an infrared sensor 5 that detects infrared rays emitted from the bottom surface of the cooking container 3 and a lower surface of the top plate 2 are placed below the top plate 2 inside the housing 1 and the cooking container 3 is placed. There are provided a contact temperature sensor 6 for detecting the temperature of the lower surface of the top plate 2 and a control means 8 for controlling the inverter 9. The control means 8 includes a temperature detection means 8a for deriving the temperature by the infrared sensor 5 and the contact temperature sensor 6, and an inverter control signal generation means 8b for controlling the inverter 9 according to the output from the temperature detection means 8a. Yes.
The infrared sensor 5 is composed of, for example, a photodiode or a thermopile that can detect a wavelength of 2.5 μm or less.

  Further, the lower surface of the top plate 2 reflects visible light to make it difficult to see the inside of the casing 1 and reflects infrared rays so that infrared rays from other than the cooking container 3 do not enter the infrared sensor 5. Layer 7 is provided. In this embodiment, a silicon or plastic-based inorganic material is used as a member for forming the reflective layer 7.

  In the present embodiment, silver having high reflectivity for visible light and infrared light is used as a reflective material that reflects the infrared light provided on the reflective layer 7. Specifically, a paint or pigment containing silver is applied, printed, or adhered to the surface of a member formed of silicon or a plastic-based inorganic material.

The reflection layer 7 described above is provided on the entire lower surface of the top plate 2. The reflective layer 7 is located above the infrared sensor 5 and has an infrared transmission region 7b that suppresses transmission of visible light and easily transmits infrared light, and a reflection region 7a that reflects visible light and infrared light outside the infrared transmission region 7b. It is composed of
Specifically, in the infrared transmission region 7b, the reflective material is applied thinly, printed or adhered as compared to the reflective region 7a, or the reflective material is applied in a dot shape or sparsely, printed or adhered.

Next, operation | movement of the induction heating cooking appliance 10 which concerns on this Embodiment is demonstrated.
When the induction heating cooker 10 is turned on by the AC power supply 11 and a predetermined temperature is set by an operation switch (not shown), electric power is supplied from the inverter 9 to the heating coil 4 under the control of the control means 8. . When electric power is supplied to the heating coil 4, an induction magnetic field is generated in the heating coil 4, and the cooking container 3 placed on the upper surface of the top plate 2 is induction-heated. Due to this induction heating, the temperature of the cooking container 3 rises, and the object to be heated in the cooking container 3 is cooked.

  Here, the operation of the infrared sensor 5 will be described. When the temperature of the cooking vessel 3 rises, infrared rays corresponding to the temperature are emitted from the cooking vessel 3. Then, the infrared light transmitted through the top plate 2 enters the infrared sensor 5. The infrared light incident on the infrared sensor 5 is converted to a voltage corresponding to the amount of infrared light and amplified. Moreover, disturbance light such as sunlight or illumination may enter the infrared sensor 5 in addition to the infrared rays radiated from the cooking container 3. These disturbance lights are reflected by the reflection region 7 a described above to prevent the incident on the infrared sensor 5.

Next, the operation of the contact temperature sensor 6 will be described. When the temperature of the cooking container 3 placed on the top surface of the top plate 2 rises, the heat of the cooking container 3 is transferred from the bottom surface of the cooking container 3 to the top plate 2 and the temperature of the top plate 2 rises. Then, the heat is transmitted to the lower surface side of the top plate 2 and the surface temperature of the lower surface of the top plate 2 is increased. The contact-type temperature sensor 6 is attached in contact with the lower surface of the top plate 2 and detects the temperature of the lower surface of the top plate 2.
With these configurations, in the present embodiment, the temperature detection means 8 a can accurately detect the temperature of the cooking container 3 based on information from the infrared sensor 5 and the contact temperature sensor 6.

  A method for estimating the temperature of the cooking container 3 in the temperature detecting means 8a will be described. First, since the infrared rays radiated from the cooking container 3 pass through the top plate 2 and enter the infrared sensor 5, the temperature data obtained by the infrared sensor 5 is corrected by the emissivity of the cooking container 3.

  Next, infrared rays are also radiated from the top plate 2 whose temperature has risen due to heat from the bottom surface of the cooking container 3, and this infrared rays also enters the infrared sensor 5, so that the contact-type temperature sensor 6 is obtained from the amount of infrared rays obtained by the infrared sensor 5. The amount of infrared rays from the top plate 2 calculated based on the temperature information of the top plate 2 obtained is subtracted, and this amount of infrared rays is taken as the amount corresponding to infrared rays from only the cooking container 3. When the amount of infrared rays only from the cooking container 3 is larger than 0, the temperature of the cooking vessel 3 is obtained by a conversion formula from the amount of infrared rays to the temperature. When the subtracted temperature data is 0 or less, the temperature data obtained by the contact-type temperature sensor 6 is set as the temperature of the cooking container 3. Thus, safety can also be ensured by obtaining the temperature of the cooking vessel 3 from the higher temperature data of the two temperature data.

  As described above, the temperature of the cooking container 3 is obtained by the temperature detecting means 8a, and based on this temperature, the inverter control signal generating means 8b accurately controls the inverter 9 and heats the cooking container 3 to a predetermined temperature. Therefore, the heated object can be cooked deliciously.

For example, in the case of heating with a set thermal power (thermal power 1 to thermal power 8 or the like), the temperature detecting means 8a is set so that the temperature of the cooking container 3 is higher than a threshold (previously 270 ° C.) set for preventing ignition. Whether it is high or below a threshold value is determined, and when it exceeds 270 ° C., the inverter control signal generation means 8b stops the output to the inverter 9 and stops heating the cooking vessel 3.
When temperature control is performed, the temperature detection means 8a determines two types of threshold values (assuming 200 ° C. and 220 ° C.), and the inverter control signal generation means 8b determines the temperature of the cooking container 3 based on these threshold values. When the temperature exceeds 220 ° C., the output to the inverter 9 is stopped and heating of the cooking container 3 is stopped. When the temperature of the cooking container 3 falls below 200 ° C., the output to the inverter 9 is started and the cooking container 3 is heated.

2, 3, 4 and 5 are diagrams showing the infrared transmission region 7b according to the present embodiment.
The infrared transmission region 7b in FIG. 2 is made of a material having a higher infrared transmittance than the reflection material provided in the reflection region 7a, or the same material as the reflection material, but the layer is made thin, A material with a reduced infrared transmittance is used. The reflective material is provided on the top plate 2 by being applied, printed or adhered.

  Thereby, the infrared rays radiated from the bottom surface of the cooking container 3 pass through the infrared transmission region 7b and enter the infrared sensor 5, and the infrared rays radiated from other than the cooking vessel 3 can be reflected by the reflection region 7a. Therefore, the temperature detection accuracy of the infrared sensor 5 can be maintained. In addition, when the cooking container 3 is not placed, the infrared transmission region 7b is provided with a reflective material that suppresses the transmission of visible light, so that it is difficult to see the internal components of the housing 1 from the infrared transmission region 7b. can do.

  In FIG. 2, the infrared transmission region 7 b may be a region provided with a reflective material so that the visible light reflectance gradually increases toward the center. Thereby, it is possible to make the internal components less visible from the infrared transmission region 7b while maintaining the temperature detection accuracy of the infrared sensor 5.

Specifically, the amount of use of the reflective material in the central portion of the infrared transmission region 7b is increased (increased the visible light reflectance), and the amount of use of the reflective material in the peripheral portion of the infrared transmission region 7b is reduced (increasing the infrared transmittance). To do). By doing in this way, since visible light reflectance becomes high in the center part of the infrared transmissive area | region 7b, while being able to make an internal component invisible, the infrared rays radiated | emitted from the cooking container 3 are peripheral parts with high infrared transmittance | permeability , And is incident on the infrared sensor 5 so that the temperature detection accuracy of the infrared sensor 5 can be maintained.
Furthermore, by using a reflective material that reflects only visible light in the infrared transmission region 7b, temperature detection with higher accuracy can be performed.

In the infrared transmission region 7b of FIG. 3, a reflective material is applied in a dot shape, printed or adhered. Infrared light and visible light are transmitted from a portion without a reflective material between the dots.
By making the reflecting material into a dot shape in this way, infrared rays radiated from the bottom surface of the cooking container 3 are transmitted through the portion without the reflecting material between the dots and enter the infrared sensor 5. It is possible to prevent the detection accuracy from being lowered. And when the cooking vessel 3 is not placed, visible light is transmitted only from a portion where there is no reflective material between the dots as in the case of infrared rays, so it is difficult to see the internal parts of the housing 1 from the outside, and the appearance is poor. I don't have to.

  Further, the dot-shaped reflecting material provided in the infrared transmitting region 7b in FIG. 3 includes (1) a material having a higher infrared transmittance than the reflecting material provided in the reflecting region 7a, and (2) the reflecting region 7a. It is not necessary to limit to either a material having a lower infrared transmittance than that of the reflective material provided in (3) or (3) a material of the same material as the reflective material provided in the reflective region 7a. In these dot-shaped reflecting materials, there is always a portion without a reflecting material between the dots, so that the infrared rays radiated from the bottom surface of the cooking container 3 pass through the portion and enter the infrared sensor 5. Thus, a constant temperature detection accuracy can be obtained by the infrared sensor 5 regardless of the material of the reflecting material. Needless to say, if the “reflecting material having a higher infrared transmittance than the reflecting material provided in the reflecting region 7a” in (1) is used, the temperature detection accuracy is further improved.

In FIG. 3, the infrared transmission region 7 b may be a region including a reflective material in which the visible light reflectance of each dot is changed so that the visible light reflectance gradually increases toward the center.
Specifically, the dots near the center increase the amount of reflection material used to increase the visible light reflectance, and the dots near the periphery decrease the amount of reflection material used and increase the infrared transmittance. By doing in this way, internal components can be made harder to see from the infrared transmission region 7b while maintaining the temperature detection accuracy of the infrared sensor 5.

In FIG. 4, in the central part of the infrared transmission region 7b, the dot-shaped reflecting material is made dense to further increase the visible light reflectance.
In this way, by concentrating the reflective material in the central portion of the infrared transmission region 7b, it is possible to efficiently use the reflective material and make it difficult to see the internal parts, so the amount of reflective material used is reduced and the cost is reduced. be able to. Also in this case, since the infrared rays pass through the portions without the reflecting material between the dots, it is possible to prevent the temperature detection accuracy of the infrared sensor 5 from being lowered.

Similar to the infrared transmission region 7b of FIG. 3, the infrared transmission region 7b of FIG. 4 can obtain a certain temperature detection accuracy by the infrared sensor 5 regardless of the material of the reflecting material.
Further, similarly to the infrared transmission region 7b in FIG. 3, the visible light reflectance of each dot is changed so that the visible light reflectance gradually increases toward the central portion in the infrared transmission region 7b in FIG. It is good also as a field provided with a reflective material. Thereby, it is possible to make the internal components less visible from the infrared transmission region 7b while maintaining the temperature detection accuracy of the infrared sensor 5.

The infrared transmission region 7b in FIG. 5 is provided with an annular region (a donut shape in FIG. 5) along which the reflecting material is not attached. Here, FIG.5 (b) is ab sectional drawing of the infrared rays transmission region 7b of Fig.5 (a).
Thereby, it is possible to make it difficult to see the internal components of the casing 1 from the infrared transmission region 7b with respect to the line of sight of the user when using the induction heating cooker 10 from an obliquely upward direction. Specifically, as shown in FIG. 5B, when the induction heating cooker 10 is viewed obliquely from above (A view), a reflective material is attached compared to when viewed from directly above (B view). Since the area not shown (the part indicated by the dotted line) becomes narrower, it becomes difficult to see the internal components of the housing 1.

  In addition, in the infrared transmission region 7b of FIG. 5, since the infrared rays radiated from the bottom surface of the cooking vessel 3 pass through the annular region where no reflective material is attached and enter the infrared sensor 5, the temperature detection of the infrared sensor 5 is performed. It is possible to prevent the accuracy from being lowered.

  Similar to the infrared transmitting region 7b having the dot-shaped reflecting material in FIGS. 3 and 4, the infrared transmitting region 7b in FIG. 5 has a gap without a reflecting material, so that it is not affected by the material of the reflecting material. In addition, the infrared sensor 5 can obtain a certain temperature detection accuracy.

  In the present embodiment, the reflective layer 7 is applied to the lower surface (rear surface) of the top plate 2, but the same effect can be obtained even when applied to the upper surface (front surface) of the top plate 2. Further, the dot shape of the reflective material is not limited to the square shown in FIG. 3 or FIG. 4, and can take any shape such as a circle, a triangle, a rhombus, and a hexagon. Furthermore, the shape of the infrared transmission region 7b is not limited to the circular shape shown in FIG. 2, FIG. 3, FIG. 4 or FIG. 5, but can take any shape such as a square or a hexagon.

  DESCRIPTION OF SYMBOLS 1 ... Housing | casing, 2 ... Top plate, 3 ... Cooking container, 4 ... Heating coil, 5 ... Infrared sensor, 6 ... Contact-type temperature sensor, 7 ... Reflection layer, 7a ... Reflection area | region, 7b ... Infrared transmission area | region, 8 ... Control means, 8a ... temperature detection means, 8b ... inverter control signal generation means, 9 ... inverter, 10 ... induction heating cooker, 11 ... AC power supply.

Claims (6)

A top plate on which the cooking container is placed and which transmits infrared rays;
A heating coil provided below the top plate for inductively heating the cooking vessel;
An infrared sensor that is provided below a cooking vessel placement region in the top plate and receives infrared rays emitted from the cooking vessel and transmitted through the top plate;
Temperature detecting means for detecting the temperature of the cooking container according to the amount of infrared light received by the infrared sensor;
Control means for controlling power supplied to the heating coil based on the temperature detected by the temperature detection means;
A reflective layer is formed by attaching a reflective material to at least one of the back surface and the front surface of the top plate, and reflects visible light and infrared light incident from above the top plate ;
An infrared transmission region provided at a position facing the infrared sensor in the reflective layer,
In the infrared transmission region, the reflective material is thinly applied, printed, or adhered as compared to the region other than the infrared transmission region in the top plate, or the reflective material is applied, printed, or adhered in a dotted or sparse manner. induction heating cooker according to claim and go infrared transmittance higher than the region other than the infrared transmission region Te. The induction heating cooker according to claim 1, wherein the infrared transmission region has a higher visible light reflectance in a central portion than in a peripheral portion. The induction heating cooker according to claim 1, wherein the infrared transmission region is formed by attaching a reflective material in a dot shape. The induction heating cooker according to claim 3, wherein the infrared transmission region has a higher visible light reflectance in a central portion than in a peripheral portion. The induction heating cooker according to claim 4, wherein the infrared transmission region has a higher density of reflector in the central part than in the peripheral part. The induction heating cooker according to claim 1, wherein the infrared transmission region is provided with an annular region not attached with a reflecting material along a peripheral edge thereof.

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