Surface heating appliances

Abstract

The objective is to reduce the power consumption of surface-type heating devices. [Solution] The present invention is a planar heating device 10 having a heating section 10 on which heater wires 32 are wired, and a temperature control unit 60 that controls the temperature of the heating section 10 based on a temperature level selected by the user. The temperature control unit 60 performs a first temperature control that controls the temperature of the heating section 10 based on a temperature level selected by the user, and then performs a second temperature control that controls the temperature of the heating section 10 based on a temperature level lower than the temperature level in the first temperature control, regardless of the user's selection.

Description

Technical Field

[0001] The present invention relates to a planar heating device.

Background Art

[0002] Conventionally, a planar heating device in which heater wires are wired along a surface has been used. In Patent Document 1, a setting signal corresponding to the position of a slide knob of a temperature adjustment unit is output to a control circuit, and when the control circuit turns on a relay based on the setting signal, the relay is turned on and off so as to reach a temperature set according to a temperature signal detected by a heat-sensitive wire. A planar heating device is disclosed. Further, the planar heating device of Patent Document 1 has two relays corresponding to each heating element, and the heating element is energized by turning on both or either of the two relays.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a planar heating device, products that suppress power consumption have been demanded due to the increasing awareness of energy conservation in recent years. An object of the present invention is to suppress the power consumption of a planar heating device.

Means for Solving the Problems

[0005] The present invention relates to a planar heating device comprising a heating section through which heater wires are wired, and a control means for controlling the temperature of the heating section based on a temperature level selected by the user, wherein the control means performs a first temperature control to control the temperature of the heating section based on a temperature level selected by the user, and then performs a second temperature control to control the temperature of the heating section based on a temperature level lower than the selected temperature level, regardless of the user's selection. [Effects of the Invention]

[0006] According to the present invention, the power consumption of a surface-type heating device can be reduced. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram schematically shows an example of the configuration of a surface-type warming device. [Figure 2] This figure shows an example of a general configuration of a cord heater. [Figure 3] This figure shows an example of the internal structure of a surface-type heating device. [Figure 4A] This diagram illustrates temperature control in normal mode. [Figure 4B] This figure shows the temperature change of the heating section in normal mode. [Figure 5A] This is a diagram illustrating temperature control in energy-saving mode. [Figure 5B] This diagram shows the temperature change of the heating section in energy-saving mode. [Figure 6] This figure shows an example of a combination of temperature level and time for the first and second temperature control in the energy-saving mode of the first embodiment. [Figure 7] This flowchart shows an example of processing performed by the control unit. [Figure 8] This figure shows an example of a combination of temperature level and time for the first and second temperature control in the energy-saving mode of the second embodiment. [Modes for carrying out the invention]

[0008] [First Embodiment] A surface-type heating device according to the first embodiment will be described with reference to the drawings. In this embodiment, the surface-type heating device is applied to an electric carpet. Figure 1 is a schematic diagram showing an example of the configuration of the surface-type heating device 100. The surface-type heating device 100 starts operating by receiving power, for example, AC 100V.

[0009] The surface heating device 100 comprises a heating section 10, a controller 20, and cord heaters 30 (30A, 30B). The heating section 10 is a flat surface where the user (user) rests to receive warmth. When viewed from above, the heating section 10 is, for example, rectangular in shape and has a large area along the horizontal direction. In this embodiment, the heating section 10 is composed of multiple (in this case, two) first heating sections 10A and second heating sections 10B by dividing the heating surface. The first heating section 10A and the second heating section 10B each occupy approximately half the area of ​​the entire heating section 10. The first heating section 10A is referred to as surface A, the second heating section 10B as surface B, and the entire heating section 10 is also referred to as the whole surface.

[0010] The heating section 10 is constructed by laminating a surface layer, a cushion layer, an insulation layer, and so on, from top to bottom. The surface layer is the part that comes into contact with the user, and can be made of materials such as felt or polyvinyl chloride (PVC). The cushion layer distributes the force applied to the heating section 10 when a user stands on it, providing elasticity to the user and retaining the heat generated by the cord heater 30. The cushion layer can be made of materials such as urethane. The insulation layer prevents the heat generated by the cord heater 30 from being radiated to the floor surface. The insulation layer can be made of materials such as felt.

[0011] The controller 20 alternately switches between energizing and de-energizing the heater wire 32 of the code heater 30 described later to control the temperature of the heating unit 10. The controller 20 is arranged at a position exposed to the heating unit 10. The controller 20 is electrically connected to a temperature selection unit 21 for the user to select the desired temperature of the heating unit 10, a surface selection unit 22 for the user to select the heating surface to be used, a notification unit 23 for notifying the user of the driving state of the surface heater 100, and a mode selection unit 24 for the user to select a mode.

[0012] The temperature selection unit 21 is, for example, a switch for the user to select the desired temperature level (e.g., Lv1 - Lv5) by sliding a knob, and the voltage corresponding to the slid position is input to the controller 20. Here, temperature level 1 corresponds to "weak" with a lower temperature of the heating unit 10, and temperature level 5 corresponds to "strong" with a higher temperature of the heating unit 10. The surface selection unit 22 is, for example, a switch for the user to select the surface to be heated, i.e., any one of the first heating unit 10A (A surface), the second heating unit 10B (B surface), and the entire heating unit 10 (entire surface) by sliding a knob. Here, although any one of the three types of surfaces can be selected, it may be possible to select from four or more types of surfaces. The surface selection unit 22 includes a switch for turning off the power of the surface heater 100.

[0013] The notification unit 23 is, for example, a light-emitting unit such as an LED, and notifies the user of the driving state of the surface heater 100 at the current time by changing the color to be lit, the lighting time, and the extinguishing time. The mode selection unit 24 is, for example, a switch for the user to select either the normal mode or the energy-saving mode of the surface heater 100. Here, although either one of the two types of modes can be selected, it may be possible to select from three or more types of modes.

[0014] The cord heater 30 generates heat by converting electricity into heat when power is supplied. The cord heater 30 is wired to the heating section 10. Specifically, the cord heater 30 is wired along the surface direction between the cushion layer and the insulation layer within the heating section 10. Alternatively, a unit in which the cord heater 30 is sandwiched from above and below by a sheet-like nonwoven fabric or other material may be created in advance, and the cord heater 30 may be wired to the heating section 10 by laminating the created unit between the cushion layer and the insulation layer. The cord heater 30 of this embodiment consists of a first cord heater 30A positioned in the first heating section 10A and a second cord heater 30B positioned in the second heating section 10B. The first cord heater 30A heats the first heating section 10A evenly by wiring it in a meandering manner in the planar direction or in a spiral manner across the entire surface of the first heating section 10A. The second cord heater 30B heats the second heating section 10B evenly by wiring it in a meandering manner in the planar direction or in a spiral manner across the entire surface of the second heating section 10B. When it is not necessary to distinguish between the first cord heater 30A and the second cord heater 30B, they will be described as cord heater 30.

[0015] Figure 2 shows an example of a schematic configuration of the cord heater 30. A so-called single-wire type cord heater is used for the cord heater 30. Specifically, the cord heater 30 includes a bobbin 31, a heater wire 32, an intermediate layer 33, a temperature detection wire 34, and an outer skin layer 35. The bobbin 31 is, for example, a polyester resin, and the heater wire 32 is disposed on the outer periphery thereof. The heater wire 32 is a conductor such as a copper alloy, for example, and is disposed so as to be spirally wound around the outer periphery of the bobbin 31. The intermediate layer 33 is a polymer layer such as a nylon resin, for example, and the temperature detection wire 34 is disposed on the outer periphery thereof. The temperature detection wire 34 is a conductor such as nickel, for example, and is disposed so as to be spirally wound around the outer periphery of the intermediate layer 33. The temperature detection wire 34 has a characteristic that its resistance value increases as the temperature rises. The outer skin layer 35 is, for example, polyvinyl chloride and is disposed on the outermost periphery. Note that the cord heater 30 is not limited to the above-described configuration and materials. For example, the heater wire 32 and the temperature detection wire 34 can be arranged in the opposite manner, or other layers can be added and arranged, and the configuration and materials can be changed as appropriate.

[0016] FIG. 3 is a diagram showing an example of the internal configuration of the planar heater 100. As shown in FIG. 3, in addition to the first cord heater 30A and the second cord heater 30B, the planar heater 100 includes a control unit 40 and various elements and circuits. The control unit 40 and various elements and circuits are disposed in the above-described controller 20. Since the configuration related to the first cord heater 30A and the configuration related to the second cord heater 30B are common, hereinafter, the configuration related to the first cord heater 30A will be mainly described, and the description of the configuration related to the second cord heater 30B will be omitted as appropriate.

[0017] In the first cord heater 30A shown in Figure 3, resistor H1a is the heater wire 32 of the first cord heater 30A, with one end of the heater wire 32 connected to contact h1a and the other end connected to contact h2a. Resistor S1a is the temperature detection wire 34 of the first cord heater 30A, with one end of the temperature detection wire 34 connected to contact s1a and the other end connected to contact s2a. The heater wire 32 and the temperature detection wire 34 are insulated from each other by an intermediate layer 33. The second cord heater 30B is configured similarly.

[0018] Furthermore, AC100V power is supplied to contacts v1 and v2 to energize the heater wires 32 of the first cord heater 30A and the second cord heater 30B. A relay switch SW and a thermal fuse TF1 are connected in series between contact v1 and contact v2. Also, a surface switch SWa and the heater wire 32 of the first cord heater 30A are connected in series between contact v1 and contact v2, and a surface switch SWb and the heater wire 32 of the second cord heater 30B are connected in series. In addition, the heater wires 32 of the surface switch SWa and the first cord heater 30A are connected in parallel with the heater wires 32 of the surface switch SWb and the second cord heater 30B.

[0019] The surface switches SWa and SWb correspond to the surface selection unit 22 described above. Specifically, when the user selects the first heating section 10A (side A) using the surface selection unit 22, surface switch SWa is turned on; when the user selects the second heating section 10B (side B), surface switch SWb is turned on; and when the user selects the entire heating section 10 (entire surface), both surface switches SWa and SWb are turned on. When the surface switch SWa is ON, the heater wire 32 of the first cord heater 30A is energized, generating heat and heating the first heating section 10A (side A). When the surface switch SWb is ON, the heater wire 32 of the second cord heater 30B is energized, generating heat and heating the second heating section 10B (side B). When both the surface switch SWa and the surface switch SWb are ON, the heater wire 32 of the first cord heater 30A and the heater wire 32 of the second cord heater 30B are energized, generating heat and heating the entire heating section 10 (all surfaces).

[0020] When the relay switch SW is ON, power is supplied to the heater wires 32 of the first cord heater 30A and the second cord heater 30B that correspond to the ON state of the surface switches SWa and SWb of the surface selection unit 22. On the other hand, when the relay switch SW is OFF, power is stopped to both heater wires 32 of the first cord heater 30A and the second cord heater 30B, regardless of the state of the surface switches SWa and SWb of the surface selection unit 22. The ON and OFF states of the switch SW are switched by the relay unit RL or the power supply control unit 50, which will be described later. In this embodiment, the relay switch SW and relay unit RL are not provided separately for the first heating unit 10A and the second heating unit 10B, but are provided in common for both. Specifically, the relay switch SW is connected in series with the heater wire 32 of the first cord heater 30A and in series with the heater wire 32 of the second cord heater 30B.

[0021] The thermal fuse TF1 is heated by the resistor TF1-R integrated with the thermal fuse TF1, and melts when it reaches a predetermined temperature or higher. When the thermal fuse TF1 melts, the power supply to the heater wire 32 is cut off even if the switch SW is on. Therefore, until the thermal fuse TF1 is replaced with a new one, the heater wire 32 of the first cord heater 30A and the heater wire 32 of the second cord heater 30B will not generate heat, and the first heating section 10A and the second heating section 10B cannot be heated.

[0022] Furthermore, a control power supply, for example, DC 5V, used for temperature control is supplied from contact u1a to contact u2a. Here, the control power supply is supplied by converting AC 100V using a voltage conversion circuit (not shown). Between contact u1a and contact u2a, a resistor R1a, a variable resistor VR1a, the temperature detection line 34 (resistor S1a) of the first cord heater 30A, and a resistor R2a are connected in series. The temperature detection line 34 of the first cord heater 30A changes the resistance S1a according to the temperature, and a DC voltage corresponding to the temperature is input to the control unit 40. Resistors R1a and R2a are resistors for voltage division so that the voltage input to the control unit 40 is an appropriate value, and the variable resistor VR1a is a resistor for adjustment according to the type (model) of the surface heating device. In addition, the smoothing circuit consisting of resistor R3a and capacitor C1a is a circuit for smoothing the voltage input to the control unit 40. The same configuration is applied between contact u1b and contact u2b.

[0023] Furthermore, the anodes of diodes D1a and D2a are connected to both ends of the temperature detection wire 34 of the first cord heater 30A, respectively, and the cathodes of diodes D1a and D2a are connected together to one end of resistor TF1-R. The anode of diode D3 is connected to the other end of resistor TF1-R, and the cathode of diode D3 is connected between the thermal fuse TF1 and the switch SW. The same configuration is applied to both ends of the temperature detection wire 34 of the second cord heater 30B.

[0024] The control unit 40 includes an electrical supply control unit 50 and a temperature control unit 60. The power supply control unit 50 controls the power supply to the heater wire 32 of the cord heater 30 so as not to supply power if the power supply to the surface heating device 100 has been on for a long time or if deterioration of the cord heater 30 is detected.

[0025] The temperature control unit 60 controls the temperature of the heating section 10, that is, the temperature of the first heating section 10A and the temperature of the second heating section 10B, based on the temperature level selected by the temperature selection unit 21. Specifically, the temperature control unit 60 compares the temperature information detected by the temperature detection line 34 with a threshold value based on the temperature level selected by the temperature selection unit 21, and, according to the result of the comparison, alternately switches the power supply to the heater wire 32 of the first cord heater 30A of the first heating section 10A and the heater wire 32 of the second cord heater 30B of the second heating section 10B, thereby controlling the temperature of the first heating section 10A and the temperature of the second heating section 10B. The temperature control unit 60 includes an AD converter 61, an AD converter 62, a table 63, a setting unit 64, an upper limit comparator 65a, a lower limit comparator 65b, a relay switching unit 66, and a storage unit 67.

[0026] The AD converter 61 converts the voltage corresponding to the temperature detected by each temperature detection line 34 into a digital signal and outputs it to the upper comparator 65a and the lower comparator 65b, respectively. The voltage corresponding to the temperature detected by each temperature detection line 34 is an example of temperature information. When the surface selection unit 22 selects the first heating section 10A (side A), the AD converter 61 converts the voltage corresponding to the temperature detected by the temperature detection line 34 of the first cord heater 30A into a digital signal and outputs it. When the surface selection unit 22 selects the second heating section 10B (side B), the AD converter 61 converts the voltage corresponding to the temperature detected by the temperature detection line 34 of the second cord heater 30B into a digital signal and outputs it. Furthermore, when the surface selection unit 22 selects the entire heating section 10 (entire surface), the AD converter 61, as a representative, converts the voltage corresponding to the temperature detected by the temperature detection line 34 of the first cord heater 30A into a digital signal and outputs it. The AD converter 62 converts the voltage corresponding to the temperature level selected by the temperature selection unit 21 into a digital signal and outputs it to the setting unit 64.

[0027] Table 63 holds information on the upper and lower threshold values ​​for each temperature level (Lv1 to Lv5) selected by the temperature selection unit 21. For example, if the upper threshold value for temperature level 1 is Vmax1, the lower threshold value for temperature level 1 is Vmin1, ... the upper threshold value for temperature level 5 is Vmax5, and the lower threshold value for temperature level 5 is Vmin5, then the relationships are Vmax5>Vmax4>Vmax3>Vmax2>Vmax1 and Vmin5>Vmin4>Vmin3>Vmin2>Vmin1.

[0028] The setting unit 64 extracts upper and lower threshold values ​​corresponding to the temperature level selected by the temperature selection unit 21 and sets them in the upper comparator 65a and lower comparator 65b, respectively. In this embodiment, the setting unit 64 varies the extracted upper and lower threshold values ​​according to the temperature level selected by the temperature selection unit 21. The detailed processing by the setting unit 64 will be described later.

[0029] The upper limit comparator 65a compares the voltage value input from the detection line input terminal (hereinafter referred to as the detection line input) which is output based on the temperature detection line 34 with the upper limit threshold, and outputs the result of the comparison to the relay switching unit 66. The lower limit comparator 65b compares the voltage value input from the detection line input with the lower limit threshold, and outputs the result of the comparison to the relay switching unit 66.

[0030] The relay switching unit 66 switches the relay unit RL on and off based on the comparison results from the upper limit comparator 65a and the lower limit comparator 65b. Specifically, the relay switching unit 66 turns on the relay unit RL when the voltage value of the detection line input is at or below the lower limit threshold. The relay switching unit 66 also turns on the relay unit RL when the voltage value of the detection line input reaches the lower limit threshold and then moves into the range between the lower limit threshold and the upper limit threshold. On the other hand, the relay switching unit 66 turns off the relay unit RL when the voltage value of the detection line input is at or above the upper limit threshold. The relay switching unit 66 also turns off the relay unit RL when the voltage value of the detection line input reaches the upper limit threshold and then moves into the range between the lower limit threshold and the upper limit threshold.

[0031] When relay unit RL is turned on, relay switch SW is turned on, and power is supplied to the heater wires 32 of the first cord heater 30A and the second cord heater 30B that correspond to the ON state of the surface switches SWa and SWb of the surface selection unit 22. On the other hand, when relay unit RL is turned off, relay switch SW is turned off, and power is stopped from both the first cord heater 30A and the second cord heater 30B.

[0032] Next, the control by the temperature control unit 60 will be explained separately for the case where the normal mode is selected in the mode selection unit 24 and the case where the energy-saving mode is selected in the mode selection unit 24. For ease of understanding, we will first explain the case where the user has selected to use only the first heating unit 10A (side A) in the surface selection unit 22, only the surface switch SWa is ON, and only the heater wire 32 of the first cord heater 30A is energized.

[0033] <Normal Mode> First, the control by the temperature control unit 60 when the normal mode is selected will be explained with reference to Figures 4A and 4B. Here, it is assumed that temperature level 5 is selected by the temperature selection unit 21. Figure 4A(a) shows the change in voltage across the temperature detection line 34 of the first cord heater 30A, and Figure 4A(b) shows the change in the energized state of the heater wire 32 of the first cord heater 30A.

[0034] In normal mode, when the power to the surface heating device 100 is turned on, the setting unit 64 extracts the upper limit threshold Vmax5 and lower limit threshold Vmin5 corresponding to the selected temperature level 5 from the table 63 and sets them in the upper limit comparator 65a and lower limit comparator 65b. As shown in Figures 4A(a) and (b), the relay switching unit 66 turns on the relay unit RL until the voltage of the temperature detection line 34 reaches the upper limit threshold Vmax5, thereby energizing the heater line 32 and causing the temperature of the first cord heater 30A to rise. Next, the relay switching unit 66 turns off the relay unit RL when the voltage of the temperature detection line 34 reaches the upper threshold Vmax 5, thereby stopping the power supply to the heater line 32 and causing the temperature of the first cord heater 30A to decrease. Subsequently, the relay switching unit 66 turns on the relay unit RL when the voltage of the temperature detection line 34 reaches the lower threshold Vmin5, thereby energizing the heater line 32 again and causing the temperature of the first cord heater 30A to rise. Similarly thereafter, the relay switching unit 66 repeatedly turns the relay unit RL on and off, thereby alternately switching the power supply to the heater wire 32 on and off, and controlling the temperature of the first heating unit 10A via the first cord heater 30A.

[0035] Figure 4B shows the change in temperature (surface temperature) of the first heating section 10A in normal mode. Although the temperature of the first cord heater 30A repeatedly rises and falls, the heat from the first cord heater 30A is transferred with a delay via the surface layer and cushion layer of the first heating section 10A, so the surface temperature of the first heating section 10A is leveled to a temperature corresponding to temperature level 5. In this explanation, we have described the case where the temperature level selected by the temperature selection unit 21 is level 5. However, even if the temperature level is other, the upper limit threshold Vmax and lower limit threshold Vmin corresponding to the temperature level selected by the temperature selection unit 21 are extracted from table 63 and set in the upper limit comparator 65a and lower limit comparator 65b, thereby controlling the surface temperature of the first heating unit 10A to a temperature corresponding to the selected temperature level.

[0036] <Energy saving mode> Next, the control by the temperature control unit 60 when the energy-saving mode is selected will be explained with reference to Figures 5A and 5B. Here, it is assumed that temperature level 5 is selected in the temperature selection unit 21. Figure 5A(a) shows the change in voltage across the temperature detection line 34 of the first cord heater 30A, and Figure 5A(b) shows the change in the energized state of the heater wire 32 of the first cord heater 30A.

[0037] In energy-saving mode, the temperature control unit 60 alternately performs the first temperature control and the second temperature control. First, the temperature control unit 60 performs the first temperature control when the power to the surface heating device 100 is turned on. (First temperature control) In the first temperature control, the setting unit 64 extracts the upper limit threshold Vmax5 and lower limit threshold Vmin5 corresponding to the selected temperature level 5 from the table 63 and sets them in the upper limit comparator 65a and lower limit comparator 65b. In other words, the first temperature control is the same process as in the normal mode, and as shown in Figures 5A(a) and (b), the relay switching unit 66 repeatedly turns the relay unit RL on and off according to the result of comparing the voltage of the temperature detection line 34 with the upper threshold Vmax5 or the lower threshold Vmin5, thereby alternately switching the energization and de-energization of the heater line 32, and controlling the temperature of the first heating unit 10A via the first cord heater 30A.

[0038] On the other hand, in energy-saving mode, unlike normal mode, the time T1 for executing the first temperature control is predetermined. The temperature control unit 60 terminates the first temperature control after the predetermined time T1 has elapsed and then executes the second temperature control. (Second temperature control) In the second temperature control, the temperature control unit 60 controls the temperature of the first heating unit 10A based on a temperature level lower than the temperature level currently selected by the user in the temperature selection unit 21. Specifically, even though the user has not changed the temperature level, the setting unit 64 extracts the upper limit threshold Vmax3 and lower limit threshold Vmin3 corresponding to a temperature level 3 lower than the temperature level 5 selected by the temperature selection unit 21 from the table 63 and sets them in the upper limit comparator 65a and lower limit comparator 65b.

[0039] Therefore, as shown in Figures 5A(a) and (b), after time T1 has elapsed, the relay switching unit 66 turns off the relay unit RL until the voltage of the temperature detection line 34 reaches the lower threshold Vmin3, thereby stopping the energization of the heater line 32, and the temperature of the first cord heater 30A decreases. Subsequently, the relay switching unit 66 turns on the relay unit RL when the voltage of the temperature detection line 34 reaches the lower threshold Vmin3, thereby energizing the heater line 32 again and causing the temperature of the first cord heater 30A to rise. Similarly thereafter, the relay switching unit 66 repeatedly switches the relay unit RL on and off, thereby alternately switching the power supply to the heater wire 32 between energizing and de-energizing, and thereby controlling the temperature of the first heating unit 10A via the first cord heater 30A.

[0040] Here, because the setting unit 64 sets the upper threshold Vmax3 and lower threshold Vmin3 corresponding to temperature level 3, the time Hon during which power is supplied to the heater wire 32 is shorter than when the upper and lower thresholds corresponding to temperature level 5 are set, thus reducing power consumption. Furthermore, assuming the ambient temperature is the same, lower temperature levels result in shorter power consumption because Hon is supplied to the heater wire 32. Furthermore, the time T2 for executing the second temperature control is predetermined. After the predetermined time T2 has elapsed, the temperature control unit 60 terminates the second temperature control and then executes the first temperature control again according to the temperature level 5 selected by the temperature selection unit 21. In other words, in energy-saving mode, the first temperature control and the second temperature control are repeated alternately.

[0041] Figure 5B shows the change in temperature (surface temperature) of the first heating unit 10A in energy-saving mode. During time T1 when the first temperature control is performed, the temperature reaches a level corresponding to temperature level 5, and during time T2 when the second temperature control is performed, the temperature drops to a level lower than temperature level 5. In this embodiment, time T2 is set so that the temperature difference ΔTp from the temperature (surface temperature) of the first heating unit 10A in the first temperature control to the temperature (surface temperature) of the first heating unit 10A in the second temperature control is within a predetermined temperature.

[0042] Monitor tests revealed that if the temperature difference ΔTp of the heating section 10 is within 5°C, users cannot perceive any change in temperature. Figure 6 shows an example of a combination of temperature levels in the first and second temperature control, and the time T1 of the first temperature control and the time T2 of the second temperature control, which allows for a temperature difference ΔTp of 5°C or less and further power saving effects.

[0043] In the example shown in Figure 6, if the selected temperature level is 5, the first temperature control sets a threshold corresponding to temperature level 5 for 15 minutes, and then the second temperature control sets a threshold corresponding to temperature level 3 for 25 minutes. In the second temperature control, instead of setting a threshold corresponding to temperature level 3 for 25 minutes, a threshold corresponding to temperature level 4, temperature level 2, or temperature level 1 may be set, or a threshold corresponding to, for example, temperature level 3.5 for energy-saving mode may be set. Here, if the upper limit threshold for temperature level 3.5 is Vmax3.5 and the lower limit threshold for temperature level 3.5 is Vmin3.5, then the relationships Vmax4>Vmax3.5>Vmax3 and Vmin4>Vmin3.5>Vmin3 are obtained. This first and second temperature control constitutes one cycle, and this cycle is repeatedly executed.

[0044] Even if the selected temperature level is between 4 and 2, in the first temperature control, a threshold corresponding to the selected temperature level is set for 15 minutes, and then in the second temperature control, a threshold corresponding to a temperature level lower than the selected temperature level is set for 25 minutes. On the other hand, if the selected temperature level is 1, the second temperature control is not performed, and the threshold corresponding to temperature level 1 is always set in the first temperature control. However, if the selected temperature level is 1, the threshold corresponding to temperature level 1 may be set for 15 minutes in the first temperature control, and then the threshold corresponding to, for example, temperature level 0.5 for energy-saving mode may be set for 25 minutes in the second temperature control. Here, if the upper limit threshold for temperature level 0.5 is Vmax0.5 and the lower limit threshold for temperature level 0.5 is Vmin0.5, then the relationships Vmax1>Vmax0.5>0 and Vmin1>Vmin0.5>0 exist. The combinations shown in Figure 6 can be determined by experiment or simulation.

[0045] Next, the processing performed by the control unit 40 of the surface-type warming device 100 will be explained with reference to the flowchart in Figure 7. In S10, the control unit 40 determines whether the power to the surface-type heating device 100 has been turned on via the surface selection unit 22. The surface selection unit 22 selects one of the following simultaneously with the power being turned on: the first heating section 10A (surface A), the second heating section 10B (surface B), or the entire heating section 10 (entire surface). However, the processing performed by the control unit 40 is the same regardless of which surface is selected.

[0046] In S11, the temperature control unit 60 initializes the data stored in the volatile memory of the storage unit 67. In S12, the control unit 40 illuminates the notification unit 23 with a color or lighting pattern that indicates the power is on, in order to let the user know that the power to the surface heating device 100 is turned on.

[0047] In S13, the temperature control unit 60 reads the program stored in the non-volatile memory of the storage unit 67 and loads it into the volatile memory. This program includes information on the temperature levels in the first and second temperature control when temperature control is performed in energy-saving mode, the time T1 of the first temperature control and the time T2 of the second temperature control, i.e., the combination information shown in Figure 6, and the order of temperature control processing.

[0048] In S14, the temperature control unit 60 obtains information on the mode selected by the mode selection unit 24 and determines whether the selected mode is an energy-saving mode. If it is an energy-saving mode, the process proceeds to S18; otherwise, it proceeds to S15.

[0049] In S15, the temperature control unit 60 performs temperature control in normal mode. The specific processing steps are explained using Figures 4A and 4B above and will be omitted here. In S16, the temperature control unit 60 determines whether a first time has elapsed since the power was turned on. Here, the first time is, for example, 4 hours. If the first time has not elapsed, the process returns to S14 and continues temperature control according to the selected mode.

[0050] In S17, the temperature control unit 60 performs temperature control with safety in mind. Specifically, if the selected temperature level is 5, the setting unit 64 extracts the upper limit threshold Vmax4 and lower limit threshold Vmin4 corresponding to temperature level 4 from table 63 and sets them in the upper limit comparator 65a and lower limit comparator 65b, thereby performing temperature control according to temperature level 4. If the selected temperature level is not 5, S17 is not performed and the process proceeds to S20.

[0051] On the other hand, if it is determined in S14 that the system is in energy-saving mode, the system proceeds to S18. In S18, the control unit 40 illuminates the notification unit 23 with a color or lighting pattern that indicates the energy-saving mode in order to let the user know that temperature control is being performed in energy-saving mode. In S19, the temperature control unit 60 performs temperature control in energy-saving mode. The specific processing steps are explained using Figures 5A, 5B, and 6 described above, and are therefore omitted here.

[0052] In S20, the temperature control unit 60 determines whether the relay unit RL has been in the ON state for a second time or longer, that is, whether the heater wire 32 has been energized for a second time or longer. Here, the second time is, for example, 10 minutes. If the heater wire 32 has been energized for a second time or longer, the process proceeds to S21; otherwise, it returns to S14. In S21, the temperature control unit 60 performs temperature control with safety in mind. Specifically, the temperature control unit 60 performs temperature control that alternates between turning the relay unit RL off for a certain period of time and then on for a certain period of time. Here, the off period is, for example, 1 minute, and the on period is, for example, 2 minutes.

[0053] In S22, the temperature control unit 60 determines whether a third period of time has elapsed since the power was turned on. Here, the third period of time is, for example, 8 hours. If the third period of time has not elapsed, the process returns to S14 and continues temperature control according to the selected mode. On the other hand, if the third period of time has elapsed, the process proceeds to S23.

[0054] In S23, the power supply control unit 50 turns off the relay switch SW for safety reasons. The control unit 40 also lights up the notification unit 23 with a color or lighting pattern that indicates the power has been turned off, so that the user is aware that the power to the surface heating device 100 has been turned off because the third time period has elapsed. After this process, the control unit 40 terminates the processing shown in the flowchart of Figure 7. If the power to the surface-type heating device 100 is turned off via the surface selection unit 22 while the flowchart of Figure 7 is being executed, the control unit 40 forcibly terminates the processing shown in the flowchart of Figure 7.

[0055] As described above, according to this embodiment, the temperature control unit 60 performs a first temperature control that controls the temperature of the heating unit 10 based on a temperature level selected by the user, and then performs a second temperature control that controls the temperature of the heating unit 10 based on a temperature level lower than the temperature level in the first temperature control, regardless of the user's selection. In this way, by controlling the temperature of the heating unit 10 based on a temperature level lower than the temperature level performed in the first temperature control, the power consumption of the surface heating device 100 can be suppressed without the user feeling a change in the temperature of the heating unit 10.

[0056] Furthermore, according to this embodiment, since the time T2 for executing the second temperature control is longer than the time T1 for executing the first temperature control, the power consumption of the surface heating device 100 can be further reduced. Furthermore, according to this embodiment, the temperature control unit 60 performs the first temperature control after performing the second temperature control. By performing the first temperature control after the second temperature control in this way, the temperature of the heating unit 10, which has decreased, can be raised.

[0057] Furthermore, according to this embodiment, the temperature control unit 60 executes the first temperature control and the second temperature control alternately after executing the second temperature control. By executing the first temperature control and the second temperature control alternately in this way, it is possible to prevent the user from feeling any temperature change in the heating unit 10.

[0058] Furthermore, according to this embodiment, the setting unit 64 sets a threshold value corresponding to the temperature level selected by the user in the first temperature control, and sets a threshold value corresponding to a temperature level lower than the temperature level selected by the user in the second temperature control. Therefore, control to suppress the power consumption of the surface heating device 100 can be performed with relatively simple processing.

[0059] Furthermore, according to this embodiment, the surface heating device 100 has a relay unit RL common to the first heating section 10A (side A) and the second heating section 10B (side B), and the temperature control unit 60 has a relay switching unit 66 that switches between a state in which power can be supplied to the relay unit RL (on) and a state in which power cannot be supplied (off). In this way, by switching the relay unit RL common to the first heating section 10A (side A) and the second heating section 10B (side B) between on and off, it is not necessary to provide a separate relay unit RL for the first heating section 10A (side A) and the second heating section 10B (side B), thus reducing the manufacturing cost of the surface heating device 100. Furthermore, regardless of whether the first heating section 10A (Side A), the second heating section 10B (Side B), or the entire heating section 10 (entire surface) is selected by the surface selection unit 22, temperature control by the temperature control unit 60 can be achieved with the same process, thereby reducing the processing burden on the temperature control unit 60.

[0060] [Second Embodiment] Next, a planar warming device according to the second embodiment will be described with reference to the drawings. Here, the focus will be on the differences from the first embodiment, and descriptions of the same configuration and processes will be omitted as appropriate. In the energy-saving mode of this embodiment, the temperature control unit 60 alternately performs the first temperature control and the second temperature control, similar to the first embodiment. However, it differs in that it varies the temperature level and time T2 applied in the first second temperature control and the temperature level and time T2 applied in the second second temperature control.

[0061] Figure 8 shows an example of a combination of temperature levels in the first and second temperature control, and the time T1 of the first temperature control and the time T2 of the second temperature control, which allows for a temperature difference ΔTp of 5°C or less and further power saving effects.

[0062] In the example shown in Figure 8, if the selected temperature level is 5, a threshold corresponding to temperature level 5 is set for 15 minutes during the first temperature control (1st time), and then a threshold corresponding to temperature level 3 is set for 25 minutes during the second temperature control (1st time). Next, a threshold corresponding to temperature level 5 is set for 15 minutes during the second temperature control (2nd time), and then a threshold corresponding to temperature level 2 is set for 20 minutes during the second temperature control (2nd time). Thus, the temperature level applied in the second temperature control is lower than the temperature level applied in the first temperature control. Also, the time T2 applied in the second temperature control is shorter than the time T2 applied in the first temperature control. This sequence of first temperature control (1st time), second temperature control (1st time), first temperature control (2nd time), and second temperature control (2nd time) constitutes one cycle, and this cycle is repeatedly executed. However, the temperature level applied in the second temperature control may be higher than the temperature level applied in the first temperature control, and the time T2 applied in the second temperature control may be longer than the time T2 applied in the first temperature control.

[0063] Next, similarly, if the selected temperature level is 4, the temperature level and time T2 applied in the first second temperature control are varied, as are the temperature level and time T2 applied in the second second temperature control. Furthermore, when the temperature level is 3 to 2, the temperature level and time T2 applied in the first second temperature control are the same as the temperature level and time T2 applied in the second second temperature control. However, the temperature level and time T2 applied in the first second temperature control are not limited to the temperature level and time T2 applied in the second second temperature control.

[0064] Next, if the selected temperature level is 1, the second temperature control is not performed, and the threshold corresponding to temperature level 1 is always set in the first temperature control. However, the temperature level and time T2 applied in the first second temperature control and the temperature level and time T2 applied in the second second temperature control may be varied.

[0065] As described above, according to this embodiment, the temperature control unit 60 varies the temperature level of the second temperature control when the first temperature control and the second temperature control are executed alternately. By varying the temperature level of the second temperature control in this way, the power consumption of the surface heating device 100 can be suppressed.

[0066] Although the present invention has been described above using the embodiments described above, the present invention is not limited to the embodiments described above, and modifications can be made within the scope of the present invention, and some of the embodiments described above may be appropriately combined with other embodiments.

[0067] In the embodiment described above, the case where the user can select from five temperature levels (1 to 5) was explained, but there may be fewer than five levels, or six or more levels. Also, in this embodiment, the case where the same number of thresholds (five types) as the number of temperature level levels selected by the user (in this case, five levels) are provided was explained, but the number of threshold types in energy-saving mode is not limited to the same number as the number of temperature level levels, and may be more or less than the number of temperature level levels.

[0068] In the embodiment described above, the case in which the heating surface of the heating section 10 is divided into two sections, a first heating section 10A (Side A) and a second heating section 10B (Side B), was explained. However, the invention is not limited to this case, and the heating section may be composed of three or more heating sections. Even in this case, each heating section has a common relay section RL, and the relay switching section 66 switches between a state in which power can be supplied to the relay section RL (on) and a state in which power cannot be supplied (off), thereby reducing the manufacturing cost of the surface heating device.

[0069] In the embodiments described above, the case where the surface heating device is an electric carpet was explained, but it is not limited to this case and may also be applied to electric mats, electric blankets, etc. Furthermore, it is not limited to AC 100V products, but can also be applied to AC 200V products. [Explanation of symbols]

[0070] 100: Surface heating device 10: Heating section 20: Controller 21: Temperature selection section 22: Surface selection section 23: Notification section 24: Mode selection section 30: Cord heater 32: Heater wire 33: Intermediate layer 34: Temperature detection wire 40: Control unit 50: Power supply control unit 60: Temperature control unit 63: Table 64: Setting unit 65a: Upper limit comparator 65b: Lower limit comparator 66: Relay switching unit 67: Memory unit

Claims

1. The heating section where the heater wires are routed, A planar warming device having control means for controlling the temperature of the warming section based on a temperature level selected by the user, The control means is A planar warming device characterized by performing a first temperature control that controls the temperature of the warming section based on a temperature level selected by the user, and then performing a second temperature control that controls the temperature of the warming section based on a temperature level lower than the first temperature level, regardless of the user's selection.

2. The planar warming device according to claim 1, characterized in that the time for performing the second temperature control is longer than the time for performing the first temperature control.

3. The control means is The planar warming device according to claim 1 or 2, characterized in that the first temperature control is performed again after the second temperature control is performed.

4. The control means is The planar warming device according to claim 1 or 2, characterized in that, after performing the second temperature control, the first temperature control and the second temperature control are performed alternately and repeatedly.

5. The control means is The planar warming device according to claim 4, characterized in that the temperature level of the second temperature control is varied when the above is repeatedly executed.

6. The heating section has a temperature detection wire that is integrated with the heater wire. The control means is A setting means for setting a threshold for comparing with the temperature information detected by the aforementioned temperature detection line, The system includes a switching means that alternately switches between supplying and stopping power to the heater wire according to the result of comparing a threshold value set by the setting means with the temperature information detected by the temperature detection line, The setting means is, In the first temperature control described above, a threshold is set according to the temperature level selected by the user, The planar warming device according to claim 1, characterized in that the second temperature control sets a threshold corresponding to a temperature level lower than the temperature level selected by the user.

7. Multiple heating units, A selection unit in which the user selects which heating unit to heat from among a plurality of heating units, It has a relay unit common to the multiple heating units, The control means is The planar heating device according to claim 1 or 2, further comprising a relay switching means for switching the relay unit on and off regardless of the heating unit selected by the selection unit.

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