JP2020135960A - Induction heating cooker - Google Patents

Abstract

To suppress enlargement of a non-contact temperature sensor in an induction heating cooker comprising the non-contact temperature sensor for detecting infrared rays from a heated object and infrared rays from a top board.SOLUTION: An induction heating cooker comprises: a top board on which an object to be heated is placed; a transmission part through which infrared rays radiated from the heated object are transmitted; a heating coil for heating the object to be heated; and a non-contact temperature sensor which is disposed at a lower side of the top board and detects a temperature of the heated object. In the induction heating cooker, the non-contact temperature sensor includes: a first light-receiving part for detecting infrared rays transmitted through the transmission part; a second light-receiving part for detecting infrared rays radiated from a region excluding the transmission part in the top board; a first condenser part for condensing the infrared rays transmitted through the transmission part to the first light-receiving part; and a second condenser part for condensing the infrared rays radiated from the region excluding the transmission part in the top board to the second light-receiving part. An optical axis of the second condenser part is configured closer to an optical axis of the first condenser part at the side of the second light-receiving part than an emission surface of the second condenser part.SELECTED DRAWING: Figure 4

Description

The present invention relates to an induction cooker including a non-contact temperature sensor.

Conventionally, in an induction heating cooker, it is known that the temperature of an object to be heated such as a pot placed on a top plate is measured by a non-contact temperature sensor. The non-contact temperature sensor is, for example, an infrared temperature sensor, which measures the temperature based on the infrared rays radiated from the object to be heated. The non-contact temperature sensor is characterized in that it is more responsive to temperature changes of the object to be measured as compared with the contact temperature sensor.

When measuring the temperature of an object to be heated using a non-contact temperature sensor, not only the infrared rays radiated from the object to be heated but also the infrared rays radiated from the top plate heated in contact with the object to be heated are received. Therefore, there is a problem that only the temperature of the object to be heated cannot be stably detected. As a countermeasure for this problem, it has been proposed that the infrared rays radiated from the object to be heated and the infrared rays radiated from the top plate are independently detected by the two light receiving units and the temperature is measured (for example, Patent Document 1). ).

Japanese Unexamined Patent Publication No. 2004-63451

Here, since the field of view of the condensing unit that collects infrared rays on the light receiving unit is fixed, the infrared rays from the object to be heated and the infrared rays from the top plate are independent of the two light receiving units in a state where the visual fields do not overlap. A certain distance is required between the two light receiving parts in order to collect light. As a result, the size of the non-contact temperature sensor becomes large, and the area where the non-contact temperature sensor can be arranged is limited. For example, in order to accurately detect the temperature of the object to be heated, it is desirable to arrange the non-contact temperature sensor near the center of the heating coil. However, as the non-contact temperature sensor becomes larger, the heating coil becomes larger. There is no choice but to place it away from the center of.

The present invention solves the above problems, and is a non-contact temperature sensor in an induction heating cooker provided with a non-contact temperature sensor that detects infrared rays from an object to be heated and infrared rays from a top plate. The purpose is to suppress the increase in size.

The induction heating cooker according to the present invention has a top plate on which the object to be heated is placed, a transmitting portion provided on the top plate through which infrared rays radiated from the object to be heated are transmitted, and heating for heating the object to be heated. It includes a coil and a non-contact temperature sensor that is arranged below the top plate and detects the temperature of the object to be heated. The non-contact temperature sensor includes a first light receiving unit that detects infrared rays that pass through the transmission unit. , The second light receiving part that detects infrared rays radiated from the area of the top plate excluding the transmitting part, and the infrared rays that are arranged between the transmitting part and the first light receiving part and pass through the transmitting part are collected in the first light receiving part. A second condensing unit that is arranged between the shining first condensing unit and the top plate and the second light receiving unit and collects infrared rays radiated from a region of the top plate excluding the transmitting portion to the second light receiving unit. The optical axis of the second condensing unit is closer to the optical axis of the first condensing unit on the side of the second light receiving unit than the emission surface of the second condensing unit.

According to the induction heating cooker of the present invention, the optical axis of the second condensing portion approaches the optical axis of the first condensing portion on the second light receiving portion side of the exit surface, so that infrared rays from the object to be heated are emitted. The first light receiving unit for detection and the second light receiving unit for detecting infrared rays from the top plate can be arranged close to each other. As a result, it is possible to suppress an increase in the size of the non-contact temperature sensor.

It is a schematic perspective view of the induction cooking apparatus in Embodiment 1. FIG. It is a schematic block diagram of the main part of the induction heating cooker in Embodiment 1. FIG. It is a figure explaining the structure of the non-contact type temperature sensor in Embodiment 1. FIG. It is a figure explaining the structure of the non-contact type temperature sensor in Embodiment 2. It is a figure explaining the structure of the non-contact type temperature sensor in Embodiment 3. It is a figure explaining the structure of the non-contact type temperature sensor in Embodiment 4. It is a side view of the 1st light receiving part and the 2nd light receiving part of Embodiment 4. FIG. It is a top view of the 1st light receiving part and the 2nd light receiving part of Embodiment 4. It is a figure explaining the structure of the non-contact type temperature sensor in the modification 1 of Embodiment 4. It is a figure explaining the structure of the non-contact type temperature sensor in the modification 2 of Embodiment 4. It is a figure explaining the structure of the non-contact type temperature sensor in the modification 3 of Embodiment 4. It is a figure explaining the structure of the non-contact type temperature sensor in Embodiment 5. It is a figure explaining the structure of the non-contact type temperature sensor in Embodiment 6.

Hereinafter, embodiments when the induction heating cooker according to the present invention is applied to a home-use IH (Induction Heating) cooker will be described with reference to the drawings. Further, the induction heating cooker shown in the drawing shows an example of the induction heating cooker of the present invention, and the application device of the present invention is not limited by the induction heating cooker shown in the drawing. Further, in the following description, terms indicating directions (for example, "top", "bottom", "right", "left", "front", "rear", etc.) are appropriately used for ease of understanding. These are for illustration purposes only and are not intended to limit the present invention. Further, in each figure, the configurations with the same reference numerals indicate the same or equivalent configurations, which are common to the entire text of the specification. In each drawing, the relative dimensional relationship or shape of each component may differ from the actual one.

Embodiment 1.
(Structure of induction heating cooker)
FIG. 1 is a schematic perspective view of the induction cooking device 100 according to the first embodiment. As shown in FIG. 1, the induction heating cooker 100 includes a main body 1 and a top plate 2 arranged on the upper surface of the main body 1. A front operation unit 3 is provided on the front surface of the main body 1. The front operation unit 3 includes a power switch for turning on / off the power of the induction heating cooker 100, a plurality of operation dials for adjusting the heating power, and the like.

The top plate 2 is composed of, for example, a heat-resistant glass plate and a metal frame attached around the glass plate. The top plate 2 is provided with a heating port 4 which is a heating region. As shown in FIG. 1, three heating ports 4 are provided in the present embodiment. The heating port 4 is printed on the top plate 2 so as to indicate an area on which an object to be heated such as a pan or a frying pan is placed. A heating coil 5 as a heating source is provided inside the main body 1 below the heating port 4. The heating port 4 is formed to have the same shape as the outer shape of the heating coil 5 which is the heating source, or a shape slightly larger than the outer shape of the heating coil 5. In the present embodiment, the heating port 4 is formed in a circular shape when viewed from above. Further, a transmission portion 40 is provided in the heating port 4 of the top plate 2. The transmission unit 40 is provided for detecting infrared rays of an object to be heated transmitted through the top plate 2 by a non-contact temperature sensor 20 (FIG. 2). The number and shape of the heating port 4 and the heating coil 5 are not limited to the example shown in FIG.

An operation display unit 6 is provided on the front side of the top plate 2. The operation display unit 6 of the present embodiment includes, for example, a display screen having a plurality of light emitting diodes (LEDs) and a capacitance type touch sensor. The touch sensor receives user operation inputs such as the heating power, temperature, and cooking mode of the heating coil 5 corresponding to each heating port 4 via the top plate 2. The display screen displays a thermal power display showing the magnitude of the thermal power set by the front operation unit 3 or the touch sensor, or information on the setting state and the operating state of the induction cooking cooker 100. Here, the information regarding the operating state of the induction heating cooker 100 includes the selected cooking mode, the progress of automatic cooking, the temperature of the object to be heated placed on the heating port 4, and the display of warning information. ..

FIG. 2 is a schematic configuration diagram of a main part of the induction cooking device 100 according to the first embodiment. FIG. 2 shows a schematic end view of the induction heating cooker 100 and a functional configuration together with the object to be heated 400 placed on the upper surface of the top plate 2. Although only one heating coil 5 is shown in FIG. 2, the structures related to the other heating coils 5 are the same as those in FIG. As shown in FIG. 2, inside the main body 1 of the induction heating cooker 100, below the top plate 2, a heating coil 5, a non-contact temperature sensor 20, a temperature detection unit 11, and a control unit 12 And an inverter 13.

The heating coil 5 is supported by the coil support 51. The coil support 51 is made of, for example, a non-magnetic metal and is supported by the housing of the main body 1. Further, the heating coil 5 of the present embodiment includes a concentric first coil 5a and a second coil 5b.

The non-contact temperature sensor 20 is an infrared temperature sensor that detects infrared energy radiated from the bottom and top plate 2 of the object to be heated 400 mounted on the heating coil 5. The non-contact temperature sensor 20 is located below the transmission portion 40 of the top plate 2, is arranged between the first coil 5a and the second coil 5b, and is supported by the coil support 51. Although not shown in FIG. 2, the non-contact temperature sensor 20 may be housed in a sensor case so that the cooling air flowing in the vicinity of the heating coil 5 does not directly hit the temperature sensor 20.

Further, the non-contact temperature sensor 20 of the present embodiment has a first light receiving portion 21 that detects infrared rays radiated from the object to be heated 400 and transmitted through the transmitting portion 40, and a region of the top plate 2 excluding the transmitting portion 40. It has a second light receiving unit 22 that detects infrared rays radiated from. As a result, the non-contact temperature sensor 20 can detect the temperature of the object to be heated 400 and the temperature of the top plate 2, respectively. The first light receiving unit 21 and the second light receiving unit 22 are photodiode, thermopile, or thermistor type infrared detection elements, respectively. The structure of the non-contact temperature sensor 20 will be described in detail later.

The temperature detection unit 11 is composed of hardware such as a circuit device that realizes the function, an arithmetic unit such as a microcomputer, and software executed on the arithmetic unit. The temperature detection unit 11 receives the output values from the first light receiving unit 21 and the second light receiving unit 22 of the non-contact temperature sensor 20, and obtains the temperature of the object to be heated 400 based on the received output values. The temperature obtained by the temperature detection unit 11 is transmitted to the control unit 12.

The control unit 12 is composed of hardware such as a circuit device that realizes the function, an arithmetic unit such as a microcomputer, and software executed on the arithmetic unit. The control unit 12 controls the operation of the induction heating cooker 100 based on the setting contents input by the operation of the front operation unit 3 or the operation display unit 6. Further, the control unit 12 controls the inverter 13 based on the cooking temperature set by the user and the temperature of the object to be heated 400 calculated by the temperature detection unit 11 to control the heating.

The inverter 13 is a drive circuit that converts the AC power supply of the commercial power supply 300 into a high-frequency current and supplies it to the heating coil 5. The induction cooking device 100 may include a configuration other than that shown in FIG. 2, and may include, for example, a communication unit that communicates with an external device. Further, the control unit 12 may have the function of the temperature detection unit 11 and the temperature detection unit 11 may be omitted.

(Configuration of non-contact temperature sensor)
FIG. 3 is a diagram illustrating the structure of the non-contact temperature sensor 20 according to the first embodiment. As shown in FIG. 3, the first light receiving unit 21 and the second light receiving unit 22 of the non-contact temperature sensor 20 are mounted on the substrate 201 and housed in the housing 200. In the example of FIG. 3, the first light receiving unit 21 and the second light receiving unit 22 are mounted on one substrate 201, but they may be mounted on different substrates. Further, in the present embodiment, the first light receiving unit 21 and the second light receiving unit 22 are arranged on the same horizontal plane.

The non-contact temperature sensor 20 has a second condensing unit 23 arranged between the transmitting unit 40 and the first light receiving unit 21, and a second condensing unit 23 arranged between the top plate 2 and the second light receiving unit 22. A light collecting unit 24 is provided. The first condensing unit 23 is a lens that condenses infrared rays from the object to be heated 400 on the first light receiving unit 21, and the second condensing unit 24 is from a region of the top plate 2 excluding the transmitting portion 40. This is a lens that collects infrared rays on the second light receiving unit 22. The first condensing unit 23 and the second condensing unit 24 are respectively configured as individual eyes of the compound eye lens 202 provided on the upper part of the housing 200.

The material and shape of the compound eye lens 202 are designed according to the distance between the first light receiving unit 21 and the second light receiving unit 22, and the shape and arrangement of the first light receiving unit 21 and the second light receiving unit 22. Further, the compound eye lens 202 may include at least two lenses, one that constitutes the first condensing unit 23 and the other that constitutes the second condensing unit 24. In FIG. 3, the compound eye lens 202 is represented by a broken line as a concept rather than an actual shape. By configuring the first condensing unit 23 and the second condensing unit 24 with the compound eye lens 202, the fields of view of the first condensing unit 23 and the second condensing unit 24 can be widened. Further, since the mutual positional relationship between the first condensing unit 23 and the second condensing unit 24 can be fixed, the detection accuracy is ensured.

The first condensing unit 23 is arranged directly below the transmitting unit 40 in order to condense infrared rays of the object to be heated 400 through the transmitting unit 40. The second condensing unit 24 may be arranged at any position of the compound eye lens 202 as long as it does not overlap the field of view of the first condensing unit 23. Specifically, in FIG. 3, the second condensing unit 24 is arranged on the left side of the first condensing unit 23, but is arranged on the right side, the front side, or the rear side of the first condensing unit 23. Also, any region of the top plate 2 excluding the transmission portion 40 can be taken into view. However, in order to accurately detect the temperature of the object to be heated 400, the field of view of the second condensing unit 24 should be as close as possible to the field of view of the first condensing unit 23.

Further, as shown in FIG. 3, the first condensing unit 23 is arranged horizontally so that the optical axis AX1 coincides with the optical axis of the first light receiving unit 21. On the other hand, the second condensing unit 24 is arranged obliquely with respect to the horizontal plane so that the optical axis AX2 is tilted with respect to the optical axis AX1 of the first condensing unit 23. More specifically, the optical axis AX2 of the second condensing unit 24 is tilted closer to the optical axis AX1 of the first condensing unit 23 on the second light receiving unit 22 side than the exit surface of the second condensing unit 24. .. In the front view of FIG. 3, the optical axis AX2 of the second condensing unit 24 is aligned with the optical axis AX1 of the first condensing unit 23 on the second light receiving unit 22 side of the exit surface of the second condensing unit 24. Cross. At this time, the focal length of the first condensing unit 23 is different from the focal length of the second condensing unit 24. By tilting the optical axis AX2 of the second light receiving unit 24 in this way, the second light receiving unit 22 can be arranged close to the first light receiving unit 21.

(Operation of induction heating cooker)
Next, the operation of the induction cooking device 100 of the present embodiment will be described. First, when the user turns on the power switch of the front operation unit 3, the control unit 12 is activated. Then, when the cooking temperature is set by the user using the operation display unit 6 or the like and the heating start is instructed, the heating coil 5 is driven by the control unit 12. Specifically, the inverter 13 is controlled by the control unit 12 so as to drive the heating coil 5 based on the temperature set by the user, and the inverter 13 supplies electric power of a predetermined frequency to the heating coil 5.

As a result, a magnetic flux is generated from the heating coil 5, and the magnetic flux generates an eddy current in the object to be heated 400 to heat the object to be heated 400. At this time, the infrared rays radiated from the object to be heated 400 pass through the transmission unit 40 and are collected by the first light receiving unit 23 to the first light receiving unit 21. The first light receiving unit 21 also detects infrared rays radiated from the top plate 2 heated by the object to be heated 400 or the heating coil 5. On the other hand, the second light receiving unit 22 detects only the infrared rays emitted from the top plate 2 and collected by the second light collecting unit 24.

The temperature detection unit 11 obtains the temperature of the object to be heated 400 based on the output value of the first light receiving unit 21 and the output value of the second light receiving unit 22, and transmits the temperature to the control unit 12. For example, the temperature detection unit 11 subtracts the output value detected by the second light receiving unit 22 from the output value of the first light receiving unit 21 to obtain the amount of infrared rays radiated from the object to be heated 400. Here, the subtraction may be performed after correcting the output value in consideration of the difference in sensitivity between the first light receiving unit 21 and the second light receiving unit 22. Then, the temperature of the object to be heated 400 is calculated from the obtained amount of infrared rays.

Then, the control unit 12 performs feedback control so that the temperature of the object to be heated 400 transmitted from the temperature detection unit 11 becomes the set temperature, and the object to be heated 400 is heated. After that, when the cooking is completed, the control unit 12 stops the inverter 13 and cuts off the power supply to the heating coil 5. With such control, the induction cooking device 100 performs automatic cooking according to the set temperature.

By configuring the non-contact temperature sensor 20 as in the present embodiment, the first light receiving unit 21 and the second light receiving unit 22 are arranged close to each other while condensing infrared rays in a wide field of view. This makes it possible to suppress the increase in size of the non-contact temperature sensor 20. As a result, the non-contact temperature sensor 20 can be arranged at a position close to the center of the heating coil 5, and the temperature detection accuracy can be improved.

Embodiment 2.
Next, Embodiment 2 of the present invention will be described. The second embodiment is different from the first embodiment in that two second light receiving units 22 and two second light collecting units 24 are provided. Other configurations and controls of the induction cooker 100 are the same as in the first embodiment.

FIG. 4 is a diagram illustrating the structure of the non-contact temperature sensor 20A according to the second embodiment. As shown in FIG. 4, the non-contact temperature sensor 20A of the present embodiment includes two second light receiving units 22a and 22b, and two second light collecting units 24a and 24b. The configurations of the two second light receiving units 22a and 22b and the two second light receiving units 24a and 24b are the same as the configurations of the second light receiving unit 22 and the second light receiving unit 24 of the first embodiment. As shown in FIG. 4, the second light receiving units 22a and 22b are arranged on both sides of the first light receiving unit 21 and mounted on the substrate 201. Further, the second condensing unit 24a collects infrared rays from the region of the top plate 2 excluding the transmitting portion 40 to the second light receiving unit 22a, and the second condensing unit 24b is the transmitting portion of the top plate 2. Infrared rays from a region other than 40 are focused on the second light receiving unit 22b. The second condensing unit 24a and the second condensing unit 24b are respectively configured as individual eyes of the compound eye lens 202. In FIG. 4, the compound eye lens 202 is represented by a broken line as a concept rather than an actual shape.

The second condensing unit 24a and 24b are arranged obliquely so that the optical axis AX2 is tilted with respect to the optical axis AX1 of the first condensing unit 23. More specifically, the optical axis AX2 of the second condensing unit 24a and 24b is the optical axis of the first condensing unit 23 on the second light receiving unit 22a and 22b side of the exit surface of the second condensing unit 24a and 24b. Tilt to approach AX1. In front view, the optical axis AX2 of the second condensing unit 24a and 24b is the light of the first condensing unit 23 on the second light receiving unit 22a and 22b side of the exit surface of the second condensing unit 24a and 24b. It intersects the axis AX1. Further, in the example of FIG. 4, the optical axis AX2 of the second condensing unit 24a and the optical axis AX2 of the second condensing unit 24b are tilted so as to approach each other on the exit side. Further, at this time, the focal length of the first condensing unit 23 and the focal lengths of the two second condensing units 24a and 24b are different. The focal length of the second condensing unit 24a and the focal length of the second condensing unit 24b may be the same or different. By tilting the optical axis AX2 of the second light receiving units 24a and 24b in this way, the second light receiving units 22a and 22b can be arranged close to the first light receiving unit 21.

By configuring the non-contact temperature sensor 20 as in the present embodiment, the area for detecting the temperature of the top plate 2 can be widened, and the temperature of the object to be heated 400 can be detected more accurately. The number of the second light receiving unit 22 and the second light collecting unit 24 may be three or more. For example, by providing four second light receiving units 22 and four second light collecting units 24 and arranging them on the front, rear, left and right sides of the first light receiving unit 21 and the first light collecting unit 23, a top plate around the transmitting unit 40 is provided. The temperature of 2 can be measured, and the temperature of the object to be heated 400 can be detected more accurately.

Further, by increasing the number of the second light receiving unit 22 and the second condensing unit 24, the temperature of the entire top plate 2 can be detected, and the temperature rises rapidly such as the occurrence of pan misalignment or empty heating. It can be applied and the safety of the induction heating cooker 100 can be improved. Further, since the plurality of second light receiving units 22 and the second light collecting unit 24 detect a plurality of different regions of the top plate 2, a slight temperature rise of the top plate 2 can be sensitively detected. As a result, the temperature of the object to be heated 400 can be kept constant without error during automatic cooking.

Embodiment 3.
Next, Embodiment 3 of the present invention will be described. The third embodiment is different from the first embodiment in the arrangement of the second condensing unit 24. Other configurations and controls of the induction cooker 100 are the same as in the first embodiment.

FIG. 5 is a diagram illustrating the structure of the non-contact temperature sensor 20B according to the third embodiment. In the first embodiment, the second condensing unit 24 is arranged obliquely with respect to the horizontal plane so that the optical axis AX2 of the second condensing unit 24 is tilted. However, the second condensing unit 24 of the present embodiment is configured. The unit 24c is arranged horizontally like the first condensing unit 23. The first condensing unit 23 and the second condensing unit 24c are respectively configured as individual eyes of the compound eye lens 202. In FIG. 5, the compound eye lens 202 is represented by a broken line as showing a concept rather than an actual shape.

Further, the second condensing unit 24c is configured such that the optical axis AX2 is tilted with respect to the optical axis AX1 of the first condensing unit 23 as in the first embodiment. In order to realize the inclination of the optical axis AX2, the second condensing unit 24c may be composed of, for example, an aspherical lens or an asymmetric lens, or may be configured by combining a plurality of lenses having different refractive indexes. Alternatively, the exit surface of the second condensing unit 24 may be processed to adjust the refractive index and tilt the optical axis AX2.

In the present embodiment, by arranging the second condensing unit 24c horizontally, the compound eye lens 202 can be made thinner, and the non-contact temperature sensor 20 can be suppressed from becoming larger in the height direction. In the present embodiment as well, as in the second embodiment, two or more second condensing units 24c and a second light receiving unit 22 may be provided.

Embodiment 4.
Next, the fourth embodiment of the present invention will be described. The fourth embodiment is different from the first embodiment in the arrangement of the first light receiving unit 21 or the second light receiving unit 22. Other configurations and controls of the induction cooker 100 are the same as in the first embodiment.

FIG. 6 is a diagram illustrating the structure of the non-contact temperature sensor 20C according to the fourth embodiment. FIG. 7 is a side view of the first light receiving unit 21 and the second light receiving unit 22 of the fourth embodiment, and FIG. 8 is a top view of the first light receiving unit 21 and the second light receiving unit 22 of the fourth embodiment. is there. In the first embodiment, the first light receiving unit 21 and the second light receiving unit 22 are arranged on the same horizontal plane, but in the present embodiment, the first light receiving unit 21 and the second light receiving unit 22 are arranged. They are placed at different positions in the height direction.

As shown in FIGS. 6 and 7, the first light receiving unit 21 is mounted on the substrate 201a fixed to the side wall of the housing 200 and is arranged above the second light receiving unit 22. The second light receiving unit 22 is mounted on the substrate 201b and is arranged at the bottom of the housing 200. The first light collecting unit 23 is configured to collect infrared rays from the object to be heated 400 on the first light receiving unit 21. Since the focal length of the first condensing unit 23 of the present embodiment is shorter than the focal length of the first condensing unit 23 of the first embodiment, the radius of curvature of the first condensing unit 23 and the like are the focal lengths. Designed for distance. Further, the second condensing unit 24 is configured to condense infrared rays from a region of the top plate 2 excluding the transmitting portion 40 to the second light receiving unit 22, as in the first embodiment.

Further, as shown in FIG. 8, in the present embodiment, the first light receiving unit 21 and the second light receiving unit 22 can be arranged so as to partially overlap in the top view. At this time, the focal point f of the second light receiving unit 22 is not shielded by the first light receiving unit 21. In this way, the first light receiving unit 21 and the second light receiving unit 22 have different positions in the height direction to change the focal length and the focal position of the first light receiving unit 23 and the second light receiving unit 24. be able to. As a result, the first light receiving unit 21 and the second light receiving unit 22 can be arranged closer to each other. As a result, it is possible to suppress the increase in size of the non-contact temperature sensor 20 and realize the size reduction.

Note that, in FIGS. 6 to 8, the first light receiving unit 21 is arranged above the second light receiving unit 22, but the present invention is not limited to this. FIG. 9 is a diagram illustrating the structure of the non-contact temperature sensor 20D in the first modification of the fourth embodiment. As shown in FIG. 9, the second light receiving unit 22 may be arranged above the first light receiving unit 21. Also in this case, the first light receiving unit 21 and the second light receiving unit 22 may be partially overlapped with each other so that the focal point f of the first light receiving unit 21 is not shielded by the second light receiving unit 22 in the top view. it can.

Further, in the present embodiment, the second light receiving unit 22 and the second condensing unit 24 may be provided by two as in the second embodiment. FIG. 10 is a diagram illustrating the structure of the non-contact temperature sensor 20E in the second modification of the fourth embodiment. Further, FIG. 11 is a diagram illustrating the structure of the non-contact temperature sensor 20F in the third modification of the fourth embodiment. FIG. 10 shows a modified example in which the first light receiving unit 21 is arranged above the second light receiving units 22a and 22b, and FIG. 11 shows a modified example in which the second light receiving units 22a and 22b are arranged above the first light receiving unit 21. An example of modification to be arranged is shown. As shown in FIGS. 10 and 11, the second light receiving portions 22a and 22b are mounted on the substrate 201b and the substrate 201c, respectively.

In the second modification, the first light receiving part 21 and the second light receiving parts 22a and 22b are partially formed so that the focal points f of the second light receiving parts 22a and 22b are not shielded by the first light receiving part 21 in the top view. Can be stacked. In the third modification, the first light receiving part 21 and the second light receiving parts 22a and 22b are partially overlapped so that the focal point f of the first light receiving part 21 is not shielded by the second light receiving parts 22a and 22b in the top view. Can be placed.

Further, the positions of the first light receiving unit 21 and the second light receiving units 22a and 22b are not limited to the above-described embodiment or modification. The positions of the first light receiving unit 21 and the second light receiving units 22a and 22b are any positions as long as the fields of view and the focal points of the first light receiving unit 21 and the second light receiving units 22a and 22b do not overlap each other. You may. For example, the second light receiving unit 22a may be arranged above or below the second light receiving unit 22b.

Embodiment 5.
Next, the fifth embodiment of the present invention will be described. The fifth embodiment is different from the first embodiment in the arrangement of the second light receiving unit 22. Other configurations and controls of the induction cooker 100 are the same as in the first embodiment.

FIG. 12 is a diagram illustrating the structure of the non-contact temperature sensor 20G according to the fifth embodiment. In the first to fourth embodiments, the first light receiving unit 21 and the second light receiving unit 22 are arranged horizontally, but in the present embodiment, the second light receiving unit 22 is arranged at an angle from the horizontal plane. Specifically, as shown in FIG. 12, when the non-contact temperature sensor 20 includes two second light receiving units 22a and 22b, the light receiving surfaces of the second light receiving units 22a and 22b are the first light receiving units, respectively. It is arranged at an angle so as to approach the portion 21.

Further, in the present embodiment, the second light receiving unit 24a that collects infrared rays in the region of the top plate 2 excluding the transmissive part 40 on the second light receiving unit 22a is arranged above the second light receiving unit 22b. .. Further, a second light receiving unit 24b that collects infrared rays in a region other than the transmitting portion 40 of the top plate 2 on the second light receiving unit 22b is arranged above the second light receiving unit 22a. Then, the second light receiving units 22a and 22b are tilted so that their optical axes coincide with the second light receiving units 24a and 24b, respectively. The angles of the second light receiving units 22a and 22b may be any angle at which light can be collected from the second light collecting units 24a and 24b.

Also in this case, the optical axis AX2 of the second condensing unit 24a and 24b is the optical axis of the first condensing unit 23 on the second light receiving unit 22a and 22b side of the exit surface of the second condensing unit 24a and 24b. Tilt to approach AX1. Further, in the example of FIG. 12, the optical axis AX2 of the second condensing unit 24a and the optical axis AX2 of the second condensing unit 24b are tilted so as to approach each other on the exit side.

With such a configuration, the arrangement area of the first light receiving unit 21 and the second light receiving units 22a and 22b can be made smaller, and the size of the non-contact temperature sensor 20 can be suppressed. Further, by tilting the second light receiving units 22a and 22b so as to face the second light collecting units 24a and 24b, light collection becomes easy. Even when only one second light receiving unit 22 is provided, the second light receiving unit 22 may be tilted and arranged. Further, instead of the second light receiving unit 22, the light receiving surface of the first light receiving unit 21 may be arranged at an angle from the horizontal plane.

Embodiment 6.
Next, a sixth embodiment of the present invention will be described. The sixth embodiment is different from the first embodiment in that it includes a transmission filter that reduces the transmittance of infrared rays having a specific wavelength. Other configurations and controls of the induction cooker 100 are the same as in the first embodiment.

FIG. 13 is a diagram illustrating the structure of the non-contact temperature sensor 20H according to the sixth embodiment. The second condensing unit 24d of the present embodiment has a transmission filter 203. The transmission filter 203 is a filter that reduces the transmittance of wavelengths other than infrared rays radiated from the top plate 2 excluding the transmission unit 40, and is attached to the second light collecting unit 24d. Other configurations of the second light collecting unit 24 are the same as those in the first embodiment. Since the second light collecting unit 24d has the transmission filter 203, the second light receiving unit 22 can predominantly detect the infrared energy radiated from the top plate 2 other than the transmission unit 40, and the top plate 2 The temperature can be measured accurately. As a result, the accuracy of heating control of the object to be heated 400 is improved, and fine temperature control becomes possible.

In the present embodiment, the first condensing unit 23 is not provided with the transmission filter 203, but the first condensing unit 23 may be provided with a transmission filter for reducing the transmittance of visible light. As a result, the non-contact temperature sensor 20 and other parts below the top plate 2 from the transmission portion 40 become inconspicuous, and the design is improved.

Further, in the present embodiment, the transmittance is changed by the transmission filter 203 provided in the second light collecting unit 24d, but the transmission filter 203 is placed between the second light collecting unit 24 and the second light receiving unit 22. A bandpass filter provided in may be used instead. Further, by providing the top plate 2 with a coating film for reducing the transmittance of a specific wavelength instead of the transmission filter 203, the same effect as that of the above embodiment can be obtained.

Further, the transmittance filter 203 may not only have a constant decrease in the transmittance of a specific wavelength, but may also have a transmittance whose transmittance is controlled by a drive voltage applied from the outside. With such a configuration, the transmittance of the transmittance filter 203 can be freely changed. In the non-contact temperature sensor 20 that detects infrared rays, a measurement error may occur due to aging. Also in this case, by controlling the transmittance with the transmittance filter 203 and periodically detecting the black body with the non-contact temperature sensor 20, calibration can be performed without disassembling the non-contact temperature sensor 20.

The above is the description of the embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist of the present invention. For example, in the above embodiment, the non-contact temperature sensor 20 is mounted on the upper part of the coil support 51, but it may be mounted below the coil support 51. Further, the non-contact temperature sensor 20 can be arranged at an arbitrary position in the region where the object to be heated 400 is placed. Considering the displacement of the pan, the position of the non-contact temperature sensor 20 closer to the center of the heating coil 5 can accurately detect the temperature of the object to be heated 400.

Further, in addition to the non-contact temperature sensor 20, a contact sensor including a thermocouple or a thermistor may be provided. By bringing the detection surface of the contact sensor into contact with the top plate 2, the heat transferred from the object to be heated 400 to the top plate 2 is detected by the contact temperature sensor. The temperature of the top plate 2 detected by the contact-type temperature sensor can be used for correcting the output value of the second light receiving unit 22 or the like.

Further, in the above embodiment, the case where the first condensing unit 23 and the second condensing unit 24 are integrally formed as the compound eye lens 202 has been described, but the present invention is not limited thereto. For example, the first condensing unit 23 and the second condensing unit 24, which are configured as individual monocular lenses, may be attached to the support and integrated. Also in this case, the optical axis AX2 of the second light receiving unit 24 is attached so as to be tilted as in the first embodiment, so that the first light receiving unit 21 and the second light receiving unit 22 are arranged close to each other. Can be done. Further, a tubular member for guiding infrared rays from the top plate 2 may be provided between the second light collecting unit 24 and the top plate 2.

Further, in the above embodiment, the optical axis AX2 of the second condensing unit 24 is tilted, but the optical axis AX1 of the first condensing unit 23 is the first than the exit surface of the first condensing unit 23. 1 On the light receiving unit 21 side, the second condensing unit 24 may be tilted so as to approach the optical axis AX2. Also in this case, the optical axis AX1 of the first condensing unit 23 and the optical axis AX2 of the second condensing unit 24 come closer to each other on the first light receiving unit 21 side than the exit surface of the first condensing unit 23. The first light receiving unit 21 and the second light receiving unit 22 can be arranged close to each other.

Further, in the above embodiment, the two light receiving units (first light receiving unit 21 and second light receiving unit 22) independently detect infrared rays from the object to be heated 400 and infrared rays from the top plate 2. However, infrared rays from the object to be heated 400 and the top plate 2 may be detected by one light receiving unit. For example, the configuration includes only the first light receiving unit 21, the first light collecting unit 23 collects infrared rays from the object to be heated 400 on the first light receiving unit 21, and the second light collecting unit 24 collects the infrared rays from the top plate 2. Of these, infrared rays from the region other than the transmission unit 40 are collected on the first light receiving unit 21. Further, the first light receiving unit 21 includes a filter capable of controlling the transmittance by a drive voltage applied from the outside. Then, the transmittance of the filter is periodically changed to provide a period for detecting only infrared rays from the object to be heated 400 and a period for detecting only infrared rays from the top plate 2, based on the output value in each period. The temperature of the object to be heated 400 may be measured. As a result, the non-contact temperature sensor 20 can be further miniaturized.

1 Main body, 2 Top plate, 3 Front operation unit, 4 Heating port, 5 Heating coil, 5a 1st coil, 5b 2nd coil, 6 Operation display unit, 11 Temperature detection unit, 12 Control unit, 13 Inverter, 20, 20A , 20B, 20C, 20D, 20E, 20F, 20G, 20H Non-contact temperature sensor, 21 1st light receiving part, 22, 22a, 22b 2nd light receiving part, 23 1st condensing part, 24, 24a, 24b, 24c , 24d 2nd condensing unit, 40 transmission unit, 51 coil support, 100 induction heating cooker, 200 housing, 201, 201a, 201b, 201c substrate, 202 compound eye lens, 203 transmission filter, 300 commercial power supply, 400 covers Heated material.

Claims (7)

The top plate on which the object to be heated is placed and
A transmissive portion provided on the top plate and transmitting infrared rays radiated from the object to be heated,
A heating coil that heats the object to be heated and
A non-contact temperature sensor, which is arranged below the top plate and detects the temperature of the object to be heated, is provided.
The non-contact temperature sensor is
A first light receiving unit that detects the infrared rays transmitted through the transmitting unit, and
A second light receiving portion that detects infrared rays radiated from a region of the top plate excluding the transmitting portion, and
A first condensing unit, which is arranged between the transmitting unit and the first light receiving unit and collects the infrared rays transmitted through the transmitting unit to the first light receiving unit.
2.
With
An induction heating cooker in which the optical axis of the second condensing unit approaches the optical axis of the first condensing unit on the second light receiving unit side of the exit surface of the second condensing unit. The induction heating cooker according to claim 1, wherein the focal length of the first condensing unit is different from the focal length of the second condensing unit. The induction heating cooker according to claim 1 or 2, wherein the non-contact temperature sensor includes two or more of the second light receiving unit and the second condensing unit. The induction heating cooker according to any one of claims 1 to 3, wherein the first light receiving unit and the second light receiving unit are located at different positions in the height direction. The induction heating cooker according to any one of claims 1 to 4, wherein the first light receiving unit and the second light receiving unit are arranged so as to partially overlap in a top view. The induction heating cooker according to any one of claims 1 to 5, wherein the light receiving surface of the second light receiving portion or the light receiving surface of the first light receiving portion is arranged so as to be inclined with respect to a horizontal plane. Further equipped with a transmission filter that reduces the transmittance of infrared rays of a specific wavelength,
The induction heating cooking according to any one of claims 1 to 6, wherein the transmission filter is provided between the top plate, the second condensing unit or the second condensing unit and the second light receiving unit. vessel.

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