JPH11304175A - Planar heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sustain an optimal surface temperature by providing a plurality of heaters arranged in a heating unit, and a temperature detector therefor integrated with the heater and then controlling the temperature of the plurality of heaters sequentially thereby detecting the temperature accurately. SOLUTION: When the temperature of an electric carpet is varied through heating of a heater 1, impedance of a temperature-sensitive material 3 is varied to cause variation in the current flowing from a temperature detecting line 2 to a heater 1. The temperature variation is detected in the form of temperature signal by a temperature detecting means 7. Since impedance of the material 3 decreases as the heater temperature increases when a relay 4 is turned on, current increases and the temperature detection signal decreased. When the temperature detection signal becomes smaller than a temperature set signal, a comparison means 6 delivers a set temperature arrival signal to a temperature control means 8 and turns the relay 4 off. Consequently, current does not flow and the means 7 delivers a constant High voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric carpet,
The present invention relates to a planar heating device such as an electric blanket and floor heating.

[0002]

2. Description of the Related Art A conventional sheet heating device of this type will be described. FIG. 11 is a block diagram of a conventional example, and FIG.
FIG. 3 is a diagram showing the arrangement of a temperature detection line 2. As shown in FIG. 12, a heater 1 and a temperature detection line 2 near the heater 1 are arranged so as to divide the heating area of the electric carpet main body into a plurality.

A system in which the temperature detecting wire 2 and the heater 1 are separately wired is called a two-wire system. When the temperature of the main body of the electric carpet changes due to the heat generated by the heater 1, the impedance of the thermosensitive material 3 changes. When the impedance of the temperature-sensitive material 3 changes, the current flowing through the temperature detection line 2 changes, and this current is taken out as a temperature detection signal to perform temperature detection. Reference numeral 4 denotes a relay for energizing the heater 1. The user sets a desired temperature in the temperature setting means 5 using a variable resistor, a push switch, or the like, and inputs this to the comparing means 6 as a temperature setting signal. In the comparison means 6,
By comparing the temperature detection signal detected by the temperature detection means 7 via the temperature detection line 2 with the temperature setting signal, the temperature control means 8
And the relay 4 is turned on / off by the temperature control means 8.
Control.

[0004] As an example, a case of a two-surface heater will be described. As a technique for controlling ON / OFF of two heaters, two heaters are simultaneously turned ON / OFF and alternately ON / OF.
F. This is because if one heater has a wattage of 400 W and is turned ON / OFF at the same time,
A total of 800 W of 400 W + 400 W at the time of ON and 0 Watts at the time of OFF are repeated. Assuming that the voltage of the AC power supply is 100 V, a commercial power contract capacity of up to about 8 A per electric carpet is required. In recent years, the contracted capacity of ordinary households has increased from 30A to 50A, but the power consumption of electrical appliances other than electric carpet has also increased, such as when an electric carpet and an air conditioner are used at the same time. The contract capacity may be exceeded and the breaker may go down.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. Sho 62-190330 and Japanese Patent Publication No. Hei 7-107654, when a plurality of heaters are alternately turned on / off, only 400 W is provided at any timing. Since power is supplied to the device, the rate of breaker down is reduced, and it has become possible to use the device together with other devices having large power consumption.

[0006]

However, the prior art has the following problems.

(1) In the case of the two-wire system in which the temperature detection line and the heater are separately wired, a felt is interposed between the heater and the temperature detection line. The distance between the heater and the temperature detection line cannot be narrowed structurally below the diameter of the detection line.

As shown in FIG. 13, it takes a certain period of time for heat generated by the heater to be conducted to the temperature detection line via the felt. For this reason, the heater must be kept ON or OFF at least during this fixed time.

In the case of the two-wire system, since the heater and the temperature detection line are far apart, a long detection time is required to detect the temperature, and the required minimum ON time and OFF time of the heater are prolonged. In the case of sequentially controlling the temperature of a plurality of heaters, if one heater has a longer ON time, the other heaters have a longer OFF time. At this time, there is a problem that the surface temperature of the turned-off current-carrying surface is reduced, the surface temperature differential is increased, and the user is uncomfortable.

(2) The conventional technique disclosed in Japanese Patent Publication No. 7-107654 will be described with reference to FIG. FIG. 14 (a)
FIG. 14 is an explanatory view of the operation of alternate energization of the planar heating device having two heaters. When the set temperature is reached before the predetermined time (α shown in FIG. The control is sequentially switched to the energization control to other heaters prior to the elapse of the predetermined time. FIG. 14B is an explanatory diagram of the alternate energization of the planar heating device when another heating device is used or in a situation where the room temperature is high such as early spring, and the set temperature is reached within a predetermined time. (Β shown in FIG. 14B) occurs. At this time, the ON / OFF time of an element such as a relay that controls the energization of the heaters A and B is a time (β) until the set temperature is reached, and the ON / OFF of the relay is performed.
The number of FFs increases. As a result, there has been a problem that the relay life is shortened due to the transfer phenomenon of the relay contacts.

In the prior art disclosed in Japanese Patent Application Laid-Open No. 62-190330, when a heater ON / OFF signal is output, a timing circuit divides the ON cycle time (constant time) of the two heaters, and the first half is divided into one cycle. The energization control of the heater (for example, heater A) is performed, and the other heater (for example, heater B) is kept off. In the latter half, the energization control of the heater B is performed, and the heater A is kept OFF. In an environment where the room temperature is relatively high, since the heater ON / OFF signal is not output, both the heaters A and B are turned off, and the heater ON / OFF signal is output when the temperature of the electric carpet decreases, and the heater is energized. Perform control. At this time, the heater A performs the energization control in the first half, and the heater B is OFF during this time. This means that the heater B cannot be energized because the heater A is in the energization control time even if the temperature of the heater B is lowered to the temperature at which the heater B should be turned on. Had a problem that it would be uncomfortable.

(3) Further, in order to meet the social demand for providing a comfortable and easy-to-use one for the user, the temperature of the entire electric carpet is averaged and the surface temperature is quickly increased to the set temperature. Although it is necessary to start up, there is a problem in that the temperature control of the heater is shortened during the alternate power supply control, and the heater temperature difference occurs unless the heater switching is performed quickly.
Further, at this time, the relay for energizing the heater is turned on.
/ OFF frequency increased, and there was a fear that the contact of the relay was welded.

(4) In addition, when the outlet into which the power plug of the electric carpet is inserted is away from the power inlet into the home, or when an extension wire or the like is used, the wiring status of the power line is changed. In a bad case, the impedance of the power supply line becomes about 2Ω. When the heaters are alternately turned ON / OFF under such a power line wiring condition, it is assumed that a current of at least about 4 A flows due to a difference between ON and OFF timings of the heater A and the heater B, and the power supply voltage is shortly applied. Will fluctuate by about 8V.
Fluctuations in the power supply voltage in conjunction with ON / OFF of the heater have a problem of causing flickering of the lighting equipment.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of heaters provided on a heating tool main body;
The temperature detecting means is configured integrally with a heater for detecting the temperature of the warming implement, and the temperature of the plurality of heaters is sequentially controlled.

According to the invention, since the temperature detecting means is formed integrally with the heater, the heat transfer time of the heat generated by the heater is short, and the temperature can be detected in a short time. When multiple heaters are energized alternately, one heater is ON
The other heater is off. The short ON time of one heater means that the OFF time of the other heater is short, and it is possible to quickly switch to the next heater. That is, it is possible to eliminate the long time required for the two-wire temperature detection and the time when the other heater is turned off needlessly.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention has a plurality of heaters disposed on a heating device main body, temperature detecting means integrally formed with the heater and detecting the temperature of the heating device main body, Temperature control means for controlling energization to the plurality of heaters, wherein the temperature control means sequentially controls the temperature of the plurality of heaters.

Since the temperature detecting means is formed integrally with the heater, the heat transfer time of the heat generated by the heater is short, and the temperature can be detected in a short time. When a plurality of heaters are energized alternately, one heater is on and the other heater is off. The shorter ON time of this one heater, on the contrary, the OF of the other heater
Since the F time is short, it is possible to quickly switch to the next heater. That is, it is possible to eliminate the long time required for the two-wire temperature detection and the time when the other heater is turned off needlessly.

Further, a plurality of heaters disposed on the warming implement main body, temperature detecting means for detecting the temperature of the warming implement main body, temperature setting means for setting the temperature of the warming implement main body to a desired temperature, Temperature control means for controlling energization of the heater;
Timer means for measuring the energization time to the plurality of heaters, wherein the temperature control means compares the temperature detection signal from the temperature detection means with the temperature setting signal from the temperature setting means, and when the detected temperature exceeds the set temperature, Alternatively, when the energization time measured by the timer means exceeds a predetermined value, a plurality of heaters to be temperature-controlled are sequentially switched, and when the heaters are switched, the switched heaters are turned on for a predetermined time.

In the case of the alternating energization control, one heater (for example, heater A) is used when the room temperature is relatively high by forcibly turning on the heater for a certain time when the heater is switched.
Even if the temperature has decreased to the temperature to be turned on, the heater A cannot be energized because the energization control time of another heater (for example, heater B) is being performed, and the temperature of the heater A does not decrease.

Also, a plurality of heaters provided in the warming implement main body, temperature detecting means for detecting the temperature of the warming implement main body, temperature setting means for setting the temperature of the warming implement main body to a desired temperature, Temperature control means for controlling energization of the heater;
Timer means for measuring the energization time to the heater, wherein the temperature control means compares the temperature detection signal from the temperature detection means with the temperature setting signal from the temperature setting means, and when the detected temperature exceeds the set temperature. Or, when the energization time measured by the timer means is equal to or more than a predetermined value, the heaters to be temperature controlled are sequentially switched, and the predetermined value of the energization time measured by the timer means is a certain time after the heater energization is started, or After the main body temperature reaches a certain temperature, the main body temperature is switched to another predetermined value.

After a certain time from the start of energization of the heater, or after the temperature of the main body reaches a certain temperature, the temperature of the electric carpet is sufficiently increased. Thus, the ON / OFF frequency of the relay for energizing the heater can be reduced, and the contact life of the relay can be extended. When the temperature of the electric carpet is low, it is necessary to quickly start up to the set temperature. However, when the surface temperature is sufficiently rising, the energizing time of the heater A is lengthened, and the OFF time of the heater B is lengthened. Even if it does, there is no problem in use because the user has already obtained a warm feeling.

Further, there is provided an energization switching means for providing a period during which a plurality of heaters are energized simultaneously for a certain period of time in which flicker does not occur at the time of energization switching of the plurality of heaters, or a period during which the plurality of heaters are not energized together. Further, the period in which a plurality of heaters are energized simultaneously or the period in which a plurality of heaters are not energized together is set to 0.5 seconds or more and 30 seconds or less.

Since a certain simultaneous energizing period or a certain non-energizing period is provided at the time of switching the energization of the heater, it is possible to prevent the lighting equipment from flickering due to the fluctuation of the power supply voltage due to the turning on of the heater.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing an embodiment when the present invention is applied to an electric carpet. The heater 1 and the temperature detection line 2 constitute a temperature-sensitive heater line 9 with a temperature-sensitive material 3 whose impedance changes depending on the temperature. FIG. 2 is a configuration diagram of the temperature-sensitive heater wire 9. A temperature sensing material 3 mainly composed of polyamide is coated on the outside of the temperature detecting wire 2, a heater 1 is spirally wound on the outside thereof, and the outside thereof is further covered with vinyl chloride. The temperature-sensitive heater wire 9 is wired to the electric carpet main body as shown in FIG. In this embodiment, two warmers are used.
Divided, the controller side is referred to as the A side, and the other side is referred to as the B side. Since the temperature control is the same for both the A and B planes,
The description will be made without discriminating between the A / B planes.

When the temperature of the electric carpet body changes due to the heat generated by the heater 1, the impedance of the temperature sensitive material 3 changes, and the current flowing from the temperature detection line 2 to the heater 1 changes. This current change is taken out as a temperature signal, and the temperature detection means 7 detects the temperature. FIG. 4 shows the characteristics of the temperature detection signal and the heater temperature. When the relay 4 is ON, the impedance of the temperature-sensitive material 3 decreases as the heater temperature increases, so that the current increases and the temperature detection signal decreases (FIG. 4D). When the temperature detection signal becomes smaller than the temperature setting signal, a signal indicating that the set temperature has been reached is input from the comparing means 6 to the temperature control means 8, and the relay 4 is turned off. In the case of the block configuration as shown in FIG. 1, no current flows when the relay 4 is in the OFF state, so that the detection signal of the temperature detecting means is H
The i voltage becomes constant (arrow in FIG. 4A). O when relay is OFF
The FF timer (not shown) keeps OFF for a certain period of time (FIG. 4B). When the OFF timer elapses a predetermined time (for example, 1.5 minutes), the relay 4 is turned on and the temperature control is started again (FIG. 4C).

The user sets a desired temperature in the temperature setting means 5 using a variable resistor, a push switch, or the like, and inputs the temperature to the comparison means 6 as a temperature setting temperature.

In this embodiment, a relay 4 is used as a power control element.
However, a switching element such as a thyristor or a triac may be used.

In this embodiment, a so-called one-wire system employing a temperature-sensitive heater wire is employed. Since the temperature of the heating element is detected, the reaction of the temperature detection is fast, and the range of temperature change is large. This means that the temperature can be accurately detected in a short time, and the ON time of the relay 4 can be set short. The fact that the ON time of the relay-4 can be set shorter during the alternate current supply control used for preventing breaker down, etc.
Can be set to be short, the differential of the heater can be reduced, and a comfortable surface temperature can be maintained.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram when the second embodiment of the present invention is applied to an electric carpet. 1 are the same as those in FIG. Also,
FIG. 6 shows an OFF timer and an ONmin timer, O
FIG. 7 is a diagram illustrating an operation of a heater by an Nmax timer. The timer means 10 starts counting from the time when the heater A or the heater B is turned on. As a result of comparison between the temperature detecting means 7 and the temperature setting means 5 by the comparing means 6, the count value of the timer means 10 has passed for a certain period of time (for example, 1.5 minutes; ONmax timer in FIG. 6) before reaching the set temperature. At times, the temperature control is switched to heater B. When the heater is switched, the count value of the timer means 10 is initialized to 0 and the heater B is turned on. The heater B is kept for a certain time (for example, 10 seconds).
The ON min timer (FIG. 6) forcibly keeps the heater ON regardless of the result of the comparing means 6. Therefore, the ON time of each heater at the time of the alternate energization is 10 seconds to 1.5 minutes. If the set temperature is reached during this time, turn off the heater
Then switch to the next heater. Each heater continues to be OFF for a certain period of time using an OFF timer (not shown) (for example, 1.5 minutes, OFF timer in FIG. 6). When a power switch (not shown) for energizing the electric carpet is operated, energization from the heater A starts. At the start of energization, ON is continued until the ONmin timer elapses, and the temperature comparison is performed from the elapse of the ONmin timer. Set temperature is reached or O
When the Nmax timer has elapsed, the heater A is turned off, and the temperature control is switched to the heater B. The heater B continues to be ON until the ONmin timer elapses in the same manner as the heater A, and then the heater B is turned off after the set temperature is reached or the ONmax timer elapses.
F.

Next, the operation at the time of switching the heater at the time of alternate energization will be described. When the heater A reaches the set temperature and the OFF timer of the heater B has elapsed, the heater B
Switch to. If the heater B off time 1.5 minutes has not elapsed, the heater A is turned off and the heater B is also turned off.
Continue FF. The heater B is turned on when the OFF time of the heater B has elapsed 1.5 minutes, and the energization control is performed. Also,
Since the OFF time of the heater B has already passed when the ONmax of the heater A has elapsed, the heater A is turned off and the switching to the heater B is performed immediately.

As described above, since the heater is forcibly turned on regardless of the detected temperature during the ONmin timer, even when the room temperature is relatively high, the degree of decrease in the temperature of the electric carpet body when the heater is turned off is reduced, and when the power is turned on alternately, The temperature drop of the heater B due to the heater A energization period can be reduced, and the temperature difference between the heater A and the heater B can be reduced.

(Embodiment 3) Embodiment 3 of the present invention will be described with reference to FIG. 7 which is a block diagram when applied to an electric carpet. 1 are the same as those in FIG. As the temperature control of each heater, the same temperature control as in the first and second embodiments is performed. Reference numeral 11 denotes a prescribed value switching means for switching prescribed values of an ONmin timer and an ONmax timer for regulating the ON time of the heater. As shown in FIG. 8, when a certain time (for example, 15 minutes) elapses from the time when a power switch (not shown) is operated, or when the temperature of each heater reaches a set temperature (for example, 35 ° C.), the temperature control unit 8 is turned on.
Is switched from 1.5 minutes to 3 minutes. Immediately after operating the power switch or when the temperature of each heater is relatively low, the temperature difference between heater A and heater B is reduced, and ONmax is used to quickly start up the electric carpet body.
It was necessary to shorten the specified time-up value of the timer. That is, since the heater B is OFF while the heater A is energized and the ONmax timer elapses or reaches the set temperature, the surface temperature does not increase, and the temperature difference between the heater A and the heater B increases. Therefore, when starting up,
The Nmax timer had to be set relatively short, 1.5 minutes. However, after 15 minutes from the start of energization,
When the temperature reaches 5 ° C, the electric carpet body is already warm enough, so even if the ONmax timer is extended to 3 minutes, the temperature difference between heater A and heater B is not uncomfortable for the user,
Further, the life of the relay can be extended.

As described above, the specified value of the ONmax timer is set to 1. after a fixed time from the start of energization or after the set temperature is reached.
By switching from 5 minutes to 3 minutes as long as possible, the life of the relay can be extended, and a highly safe electric carpet with few component failures can be supplied.

(Embodiment 4) Further, Embodiment 4 of the present invention will be described with reference to FIG.
This will be described with reference to FIG. 1 are the same as those in FIG. As the temperature control of each heater, the same temperature control as in the first and second embodiments is performed. Reference numeral 12 denotes an energization switching means for providing a period during which the heaters A and B are simultaneously turned on for a certain period of time when switching between the heaters A and B at the time of alternate energization, or by turning off the heaters A and B at the same time. Period. Heater A and heater B are simultaneously O
The period during which N is performed will be described with reference to FIG. FIG.
0, the heater A is energized at the time of alternate energization, and the heater A
If the OFF time of the heater B has elapsed when the ONmax timer has elapsed or when the set temperature has been reached, the heater B is turned on while the heater A remains ON. At this time, counting starts with a flicker timer (not shown), and the heater A is turned off when the flicker timer elapses a predetermined time (for example, 5 seconds). Similarly, when switching from the heater B to the heater A, the heater B is turned off when the flicker timer has elapsed for 5 seconds, and the power supply to the heater A is controlled. That is, for 5 seconds, a period in which the heaters A and B are simultaneously turned on is provided. During this period, the power supply voltage decreases due to the power consumption of the heaters A and B, and the illuminance of the lighting fixtures taken from the same outlet decreases. I do. If the illuminance of the luminaire is short, the user feels flickering, but if the illuminance decreases for a relatively long period of 5 seconds, there is no feeling of flickering.

Next, a period during which the heaters A and B are simultaneously turned off will be described. As shown in the case where ON is not repeated at the time of switching the energization of the heater in FIG.
When the Nmax timer elapses or the set temperature is reached, the heater A is turned off, and the flicker timer (not shown)
Start counting with. If the OFF time of the heater B has elapsed when the flicker timer has elapsed for 5 seconds, the heater B is turned ON. Similarly, the switching of the energization from the heater B to the heater A is also performed when the ONmax timer of the heater B elapses or when the set temperature is reached.
F, if the OFF time of the heater A has elapsed, the heater A
Turn ON. Thus, the heaters A and B are simultaneously
A period during which the FF is performed is provided for 5 seconds or more. During this period, the power consumption of the heater is zero, and the power supply voltage increases. At this time, the lighting fixtures taken from the same outlet increase the illuminance, but for a relatively long period of 5 seconds, the user does not feel that the lighting fixture flickers.

The period in which the flicker is felt is about 0.5 seconds to 30 seconds, although there are differences depending on the person and the environment. The flicker timer of 5 seconds in the fourth embodiment is an example.

As described above, by providing the simultaneous ON period or the simultaneous OFF period of the heaters A and B at the heater switching timing at the time of the alternate power supply, the minimum time during which the power supply voltage fluctuates is ensured, and No fluctuations can be given to the user.

[0039]

As described above, according to the structure of the present invention, the following effects can be obtained.

(1) Since the temperature detecting means is formed integrally with the heater, the heat transfer time of the heat generated by the heater is short, and the temperature can be detected in a short time.

When a plurality of heaters are energized alternately, one heater is on and the other heater is off. The short ON time of one heater means that the OFF time of the other heater is short, and it is possible to quickly switch to the next heater. That is, it is possible to eliminate the long time required for the two-wire temperature detection and the time when the other heater is turned off needlessly.

(2) Since the heater is of a one-line type, the heater temperature can be accurately controlled without being affected by the room temperature or the surrounding environment, and fine and comfortable temperature control is hardly affected by the state of the non-conductive surface. be able to. Furthermore, compared to the two-wire system, the number of wiring steps can be reduced and the number of wirings in the controller can be reduced, so that the controller can be reduced and an inexpensive electric carpet can be supplied.

(3) In the case of the alternating energization control, by forcibly turning on the heater for a certain time when the heater is switched, one heater (heater A) drops to a temperature to be turned on when the room temperature is relatively high. Therefore, the heater B cannot be energized because the energization control time of the other heater (heater B) is being performed, so that a decrease in the temperature of the heater B can be reduced.

(4) After a certain time from the start of energization of the heater,
Alternatively, by changing the energizing time to the heater longer after the body temperature reaches a certain temperature, the ON / OFF frequency of a relay for energizing the heater can be reduced, and the contact life of the relay can be extended.

(5) Since a certain simultaneous energizing period or a certain non-energizing period is provided at the time of switching the energization of the heater, it is possible to prevent the lighting equipment from flickering due to the fluctuation of the power supply voltage due to the turning on of the heater.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electric carpet according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a temperature-sensitive heater wire of the present invention.

FIG. 3 is a perspective view of the electric carpet according to the first embodiment of the present invention.

FIG. 4 is a temperature characteristic diagram of the temperature-sensitive heater wire according to the first embodiment of the present invention.

FIG. 5 is a block diagram of an electric carpet according to a second embodiment of the present invention.

FIG. 6A is an explanatory diagram of heater control when the heater A is turned off after the lapse of the OFF time of the heater B according to the second embodiment of the present invention.
Explanatory diagram of heater control when F is performed

FIG. 7 is a block diagram of an electric carpet according to a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of an operation of a specified value switching unit according to a third embodiment of the present invention.

FIG. 9 is a block diagram of an electric carpet according to a fourth embodiment of the present invention.

FIG. 10 (a) is an explanatory diagram of a heater switching operation in the case where ON is superimposed at the time of energization switching of the heater according to the fourth embodiment of the present invention.

FIG. 11 is a block diagram of a conventional electric carpet.

FIG. 12 is a perspective view of a conventional electric carpet.

FIG. 13 is a characteristic diagram of a distance between a heater and a temperature detection line and a heat transfer time.

14A is a diagram for explaining a conventional heater control operation at the time of alternate energization, and FIG. 14B is a diagram for explaining a conventional heater control operation at the time of room temperature is high.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heater 2 Temperature detection line 3 Temperature sensing material 4 Relay 5 Temperature setting means 6 Comparison means 7 Temperature detection means 8 Temperature control means 9 Temperature sensing heater wire 10 Timer means 11 Specified value switching means 12 Electricity switching means

Claims (5)

[Claims] 1. A plurality of heaters disposed on a main body of a warming tool,
The temperature control unit is configured integrally with the heater and detects a temperature of the main body of the heating device, and a temperature control unit that controls energization to the plurality of heaters, and the temperature control unit sequentially controls the plurality of heaters. A planar heater with a controlled structure. 2. A plurality of heaters disposed on a body of a warming tool,
Temperature detecting means for detecting the temperature of the warming implement body, temperature setting means for setting the temperature of the warming implement body to a desired temperature, temperature control means for controlling energization to a plurality of heaters, and a plurality of Timer means for measuring an energization time to the heater, wherein the temperature control means has detected a temperature equal to or higher than the set temperature by comparing a temperature detection signal from the temperature detection means with a temperature setting signal from the temperature setting means. When the energization time measured by the timer means is equal to or longer than a predetermined value, a plurality of heaters to be temperature-controlled are sequentially switched, and when the heaters are switched, the switched heaters are turned on for a predetermined time. Utensils. 3. A plurality of heaters provided in a warming tool main body,
Temperature detecting means for detecting the temperature of the warming implement body, temperature setting means for setting the temperature of the warming implement body to a desired temperature, temperature control means for controlling energization to a plurality of heaters, and a plurality of Timer means for measuring an energization time to the heater, wherein the temperature control means has detected a temperature equal to or higher than the set temperature by comparing a temperature detection signal from the temperature detection means with a temperature setting signal from the temperature setting means. When the energization time measured by the timer means is equal to or longer than a predetermined value, the heaters to be temperature controlled are sequentially switched, and the predetermined value of the energization time measured by the timer means is constant from the start of energization of the heater. A planar heating device configured to switch to another predetermined value after a time or after the body temperature reaches a certain temperature. 4. A period in which a plurality of heaters are simultaneously energized for a certain period of time in which flicker does not occur when the energization of the plurality of heaters is switched,
4. The planar warming tool according to claim 1, further comprising an energization switching unit that provides a period during which none of the plurality of heaters is energized. 5. 5. A period in which a plurality of heaters are energized simultaneously or a period in which a plurality of heaters are not energized together is set to 0.5 seconds or more.
The planar warming device according to claim 4, wherein the heating time is within 0 seconds.