JP7089915B2 - Heat generator - Google Patents

Description

The present invention relates to a heat generating device, and more particularly to a heat generating device for heating housing equipment.

Heat-generating devices that heat housing equipment such as heating toilet seats are known. For example, in Patent Document 1, the applicant has disclosed a technique relating to a heated toilet seat that warms a seating surface by heating a heating element. The heating toilet seat described in Patent Document 1 includes a heating element that heats the toilet seat surface, a control means for supplying power to the heating element, and the like.

Japanese Unexamined Patent Publication No. 2012-045027

In order to improve the comfort of users who use the equipment, heat generating devices that heat the equipment are increasingly installed. For example, the heated toilet seat is heated by a thin film heating element having a folded shape, which reduces discomfort when the buttocks come into contact with the toilet seat and improves user comfort. On the other hand, it is not desirable to constantly energize the heating element because it leads to wasteful energy consumption. Therefore, it is conceivable that the power is turned off when the user is not using it and the power is turned on when the user is using it. With such a heated toilet seat, if it takes a long time for the cold toilet seat to reach a comfortable temperature (hereinafter referred to as "startup time"), the user may wait for a long time or sit on the toilet seat before the temperature rises. It is not easy to use.

Therefore, the inventors have repeated research from the viewpoint of shortening the start-up time of the heating device by passing a large current through the heating element, and obtained the following findings.
First, a large current was passed through a thin film heating element having a folded pattern provided on a resin-made heating element, and the distribution of the temperature rise was examined. As a result, in the bent portion of the folded pattern of the heating element, a phenomenon was observed in which the temperature of the inner portion of the bend locally rises, and the resin of the heated object melts or the printed wiring is cracked at that portion. .. As a result of the analysis, it was found that this was due to the fact that the current was concentrated inside the bending at the bending part of the heating element, causing a large bias in the temperature distribution.

That is, at the bent portion, the inner current path having a smaller radius is shorter and the resistance value is smaller than the outer current path having a large radius, so that the Joule heat inversely proportional to the resistance value is larger inside than the outer side. When heating slowly, the heat is dispersed to the surroundings by heat conduction, and it is possible to suppress a local temperature rise. However, when heated in a short time, the dispersion due to heat conduction cannot catch up and the local temperature rise becomes large. Since the local temperature rise becomes significantly larger as the current of the heating element is increased, there is an antinomy between shortening the start-up time and suppressing the local temperature rise. Such a problem may also occur in a heating device other than the heating toilet seat.

From these, the present inventors recognized that the conventional heat generating apparatus has a problem to be improved from the viewpoint of reducing the bias of the temperature distribution of the heating element and suppressing the local temperature rise.

An object of the present invention has been made in view of such a problem, and an object of the present invention is to provide a heat generating apparatus capable of reducing a bias in the temperature distribution of a heating element.

In order to solve the above problems, the heating device according to an embodiment of the present invention is a heating device including a thin film-shaped heating element having a bent portion, and the heating element causes a bias in the current distribution in the width direction of the bent portion. It has a current difference reducing unit for reducing the current difference.

According to this aspect, since the current difference reducing portion is provided, the bias of the temperature distribution in the width direction of the bent portion can be reduced.

It should be noted that any combination of the above components and those in which the components and expressions of the present invention are mutually replaced between methods, systems and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to provide a heat generating device capable of reducing the bias of the temperature distribution of the heating element.

It is a top view which shows the heat generation apparatus of 1st Embodiment. FIG. 3 is an enlarged plan view showing a part of a heating element of the heating device of FIG. 1. FIG. 2 is a cross-sectional view taken along the line AA of the heating element of FIG. It is a top view which shows the heating element of the comparative example. FIG. 3 is a cross-sectional view taken along the line BB of the heating element of FIG. It is a figure explaining the flow of the electric current of the heating element of FIG. It is a figure which shows the temperature distribution of the heating element of FIG. It is a figure which shows the equivalent circuit of the heating element of FIG. It is a figure which shows the temperature distribution of the heating element of the heating element of FIG. It is a top view which enlarges and shows a part of the heating element of the heating element of the 2nd Embodiment. It is a figure which shows the equivalent circuit of the heating element of FIG. It is a figure which shows the temperature distribution of the heating element of FIG. It is a top view which enlarges and shows a part of the heating element of the heating element of the 3rd Embodiment. FIG. 3 is a sectional view taken along line CC of the heating element of FIG. It is a figure which shows the temperature distribution of the heating element of FIG. It is a top view which shows the state which excised the outer region from the heating element of FIG.

Hereinafter, the present invention will be described with reference to each drawing based on a preferred embodiment. In the embodiments and modifications, the same or equivalent components and members are designated by the same reference numerals, and duplicate description thereof will be omitted as appropriate. Further, the dimensions of the members in each drawing are shown in an appropriately enlarged or reduced size for easy understanding. In addition, some of the members that are not important for explaining the embodiment in each drawing are omitted and displayed.

In addition, although the term including the ordinal numbers such as 1st and 2nd is used to explain various components, this term is used only for the purpose of distinguishing one component from the other components, and this term is used. The components are not limited by.

[First Embodiment]
The heat generating device according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a plan view showing an example of the heat generating device 100 of the first embodiment. The heating device 100 is a heating toilet seat that is heated by a heating element. The heating device 100 includes a heating element 10 and a heating element 30. The heated body 30 of the present embodiment is, for example, a toilet seat made of a resin such as polypropylene. The heated body 30 is a hollow annular member having a substantially oval shape that is long in the left-right direction in FIG. The heating element 10 includes a thin film-shaped resistor provided along the heated element 30. The heating element 10 has a folded pattern in which a plurality of bent portions 12 and extended portions 14 extending from the bent portions 12 are connected. The heating element 10 generates Joule heat by supplying an electric current from the terminal 16a to the terminal 16b, and warms the heated element 30.

(Heating element)
FIG. 2 is an enlarged plan view showing a part of the heating element 10. FIG. 3 is a sectional view taken along line AA of the bent portion 12 of the heating element 10. Hereinafter, as shown in FIG. 2, the side having a small radius of curvature of bending is referred to as "inside", and the side having a large radius of curvature of bending is referred to as "outside". Further, as shown in FIG. 3, the direction from the inside to the outside along the normal of bending is referred to as "width direction". Further, the thickness direction of the heating element 10 (left-right direction in FIG. 3) is referred to as a "thickness direction". The bent portion 12 of the present embodiment is bent in an arc shape. The stretched portion 14 of the present embodiment extends linearly from both ends of the bent portion 12. Therefore, the heating element 10 in this portion exhibits a U-shape in the opposite direction. The heating element 10 of the present embodiment has a current difference reducing portion 20 for reducing the bias of the current distribution (hereinafter, simply referred to as “current distribution”) in the width direction of the bending portion 12. The current difference reducing unit 20 will be described later.

(Comparative example)
Here, before explaining the heating element 10 of the present embodiment, the heating element 510 of the comparative example will be described with reference to FIGS. 4 to 7. FIG. 4 is a plan view showing a heating element 510 according to a comparative example. FIG. 5 is a sectional view taken along line BB of the heating element 510. The heating element 510 of the comparative example is different from the heating element 10 of the present embodiment in that it does not have the current difference reducing unit 20, and the other configurations are the same. The heating element 510 has a bent portion 12 and a stretched portion 14. The bent portion 12 of the comparative example does not have a separating portion described later, is continuous in the width direction, and has a constant thickness.

With reference to FIG. 6, how the current flows in the heating element 510 of the comparative example will be described. FIG. 6 is a diagram illustrating how a current flows in the heating element 510. This figure schematically shows how the current I flowing from the stretched portion 14 is concentrated inward in the bent portion 12. In a linearly extending current path, the path length is constant regardless of the position in the width direction, so that the current is uniformly diffused and flows in the width direction. However, since the radius of curvature is small inside the bent portion, the path length is short and the electrical resistance (hereinafter, simply referred to as “resistance”) is small, and the outside of the bent portion has a large radius of curvature, so the path length is long and the resistance is large. Since the voltage drop is constant inside and outside, the current concentrates on the inside where the resistance is small, avoiding the outside where the resistance is large. In this case, the current density is inversely proportional to the radius of curvature, so the larger the internal / external ratio of the radius of curvature, the larger the external / internal ratio of the current density.

FIG. 7 is a diagram showing the temperature distribution of the heating element 510 of the comparative example. Since the heat generated in the heating element 510 is spread over the entire heating element 510 by heat conduction, the temperature is made uniform in each part of the heating element 510 with the passage of time, but this figure shows before the homogenization by heat conduction occurs. Shows the initial state of. In this figure, T1 (not shown) is the atmospheric temperature, which indicates that the temperature is relatively high in the order of T2, T3, T4, T5, T6, T7, T8, and T9. Further, the temperature difference between each step of T1 to T9 is 4 deg.

In this example, T5 is the average temperature of the heating element 510, with T6, T7, T8, and T9 being relatively hot, and T4, T3, and T2 being relatively cold. This figure shows that at the outermost part of the bent portion 12, the temperature is T2, which is considerably lower than that of T5, and almost no current flows. Further, this figure shows that the temperature of the innermost part of the bent portion 12 is T9, which is considerably higher than that of T5, and the current is concentrated and flows.

The temperature difference between the high temperature part and the low temperature part of the temperature distribution (hereinafter, simply referred to as “temperature difference”) is considered to be substantially proportional to the square of the current according to Joule's law. Therefore, when a large current is passed through the heating element 510 in order to shorten the start-up time of the heating device, the temperature inside the bent portion 12 becomes significantly high. If this temperature exceeds the heat-resistant temperature or melting point of the resin constituting the heated body 30, melting, deformation, cracking or the like occurs at that portion.

The present embodiment will be described with reference to FIGS. 2 and 3. It has been confirmed by the simulations of the inventors that the temperature distribution of the heating element substantially matches the current distribution of the heating element. Therefore, by reducing the bias of the current distribution, the bias of the temperature distribution of the heating element can be reduced. Therefore, the heating element 10 of the present embodiment has a current difference reducing portion 20 for reducing the bias of the current distribution in the width direction of the bent portion 12.

(Current difference reduction unit)
The current difference reducing portion 20 of the present embodiment includes a separating portion that separates the bent portion 12 into a plurality of current paths in the width direction. Each width of the plurality of current paths may be set so that the difference between the resistance values of the plurality of current paths is small. In the example of FIG. 2, the bent portion 12 includes three current paths 12a, 12b, 12c separated in the width direction by two separating portions 18a, 18b. The current paths 12a, 12b, and 12c are arranged from the outside to the inside in this order, and are semicircular current paths having a constant width.

The separating portions 18a and 18b may be those that can be electrically separated between the current paths 12a, 12b and 12c, and in this example, the band-shaped or streaks in which the resistor of the heating element 10 is not substantially formed. It is a shaped slit. The separation portions 18a and 18b of this example have a semi-arc shape. The separation portion may be provided continuously or may include an intermittent portion in a part thereof.

FIG. 8 is a diagram showing an equivalent circuit of the heating element 10 of the present embodiment. Since the bent portion 12 is separated into the current paths 12a, 12b, and 12c, each current path has independent resistances Ra, Rb, and Rc, and current flows independently. The current in each current path is inversely proportional to the resistance values of the resistors Ra, Rb, and Rc according to Ohm's law. Therefore, the respective currents can be controlled by adjusting the resistance values of the resistors Ra, Rb, and Rc. In FIG. 8, Ra, Rb, and Rc are represented by symbols of a plurality of resistances connected in series, each of which means one resistance. The resistance Rd of the stretched portion 14 is connected to both ends of the resistances Ra, Rb, and Rc.

The radii ra, rb, rc inside the current paths 12a, 12b, 12c have a relationship of ra> rb> rc. Further, the widths Wa, Wb, and Wc of the current paths 12a, 12b, and 12c may be set so that the difference between the resistance values of the resistors Ra, Rb, and Rc of the current paths 12a, 12b, and 12c becomes small. Specifically, the widths Wa, Wb, and Wc are set in the relationship of Wa> Wb> Wc. The thicknesses Da, Db, and Dc of the current paths 12a, 12b, and 12c are equal to each other. Since the resistance of each current path is proportional to the radius and inversely proportional to the width, the resistance ratio of each current path is smaller than the ratio of the radii ra, rb, rc, and the current to the outside is increased to concentrate the current to the inside. Can be alleviated.

FIG. 9 is a diagram showing the temperature distribution of the heating element 10 of the present embodiment. As shown in this figure, the temperature of the outermost part of the bent portion 12 is higher than that of the comparative example at T3, the current around this is increased, and the bias of the temperature distribution is alleviated as compared with the comparative example. There is.

The width Wa, Wb, Wc and the radius ra, rb, rc may be set so that the resistance values of the resistances Ra, Rb, and Rc of each current path are equal to each other. For example, the widths Wa, Wb, Wc and radii ra, rb, rc may be set so that ra / Wa, rb / Wb and rc / Wc are equal to each other.

In the description of FIG. 3, the thicknesses Da, Db, and Dc of the current paths 12a, 12b, and 12c may be set so that the difference between the resistance values of the resistors Ra, Rb, and Rc is small. Specifically, the thicknesses Da, Db, and Dc may be set in the relationship of Da> Db> Dc. In this case, the current concentration inward can be further relaxed. The number of current paths, the width of the current paths and the thickness of the current paths can be set by simulation according to the desired characteristics.

Next, a method for manufacturing the heating element 10 will be described. The heating element 10 can be manufactured by various known thin film pattern manufacturing methods. As an example, the heating element 10 may be manufactured by etching, pressing, plating, vapor deposition, printing, or a combination thereof. The heating element 10 of this embodiment is formed by screen printing or dispenser printing. In dispenser printing, for example, a heating element is printed by applying a raw material paste that becomes a heating element while tracing the discharge port of the dispenser along a printing portion. In this case, a high-precision heating element can be manufactured without using large-scale equipment. Further, by manufacturing the heating element by printing, it is possible to easily manufacture the heating element by changing the thickness of each portion (for example, each current path) of the heating element.

The heating element 10 may be directly formed on the heated body 30, or the heating element 10 formed on a base material such as a resin film may be attached to the heated body 30. Further, the heating element 10 formed on the jig may be transferred to the heated body 30.

In the example of FIG. 1, an example in which the heated body 30 of the heat generating device 100 is a toilet seat is shown, but the applicable range of the heat generating device 100 is not limited to this. The heating device 100 may be applied to housing equipment including walls, floors, glass, tables, desks, chairs, bathtubs or windows. The above is the description of the heat generating device 100 of the first embodiment.

[Second Embodiment]
Next, the heat generating device according to the second embodiment of the present invention will be described with reference to FIGS. 10 to 12. FIG. 10 is an enlarged plan view showing a part of the heating element 210 of the heating device 200 of the second embodiment. The cross section of the bent portion 12 of the heating element 210 is the same as that of the first embodiment. The heating device 200 of the present embodiment is different from the heating device 100 of the first embodiment in that the configuration of the separating portion of the heating element 210 is different, and the other configurations are the same. The separation portion of the present embodiment has an extension portion extending from the bending portion to the extension portion. By having the extension portion, the extension portion is separated into a plurality of current paths in the width direction.

The separation portion of the example of FIG. 10 has extension portions 18c and 18d extending from both ends of the separation portions 18a and 18b to the extension portion 14. The extension portion 14 of the present embodiment includes three current paths 14a, 14b, 14c by two extension portions 18c, 18d. FIG. 11 is a diagram showing an equivalent circuit of the heating element 210. Since the stretched portion 14 is separated into the current paths 14a, 14b, and 14c, each current path has resistances Re, Rf, and Rg, respectively.

Therefore, the current path 14a and the current path 12a are connected in series and have the resistance Rae represented by the equation (1).
Rae = Ra + 2 ・ Re ・ ・ (1)
Further, the current path 14b and the current path 12b are connected in series and have the resistance Rbf represented by the equation (2).
Rbf = Rb + 2 ・ Rf ・ ・ (2)
Further, the current path 14c and the current path 12c are connected in series and have the resistance Rcg represented by the equation (3).
Rcg = Rc + 2 ・ Rg ・ ・ (3)

Since the current paths 14a, 14b, 14c are connected in series to the current paths 12a, 12b, 12c, the magnitudes of the resistance values of the resistors Rae, Rbf, and Rcg of each current path approach each other, and the current flowing inward and the outside The difference in the current flowing through is small. FIG. 12 is a diagram showing the temperature distribution of the heating element 210. As shown in this figure, the region of the outermost temperature T3 of the bent portion 12 is narrower than that of the first embodiment, and the current around this region is increasing. Further, the innermost temperature of the bent portion 12 is T6, which is lower than that of the first embodiment, and the current concentration on this portion is further relaxed. Compared with the first embodiment, the difference in temperature between the inside and the outside of the bent portion 12 is small, and the bias of the temperature distribution is alleviated as a whole.

The stretch lengths of the extension portions 18c and 18d can be set by simulation according to the desired characteristics. The above is the description of the heat generating device 200 of the second embodiment.

[Third Embodiment]
Next, the heat generating device according to the third embodiment of the present invention will be described with reference to FIGS. 13 to 15. FIG. 13 is an enlarged plan view showing a part of the heating element 310 of the heating device 300 of the third embodiment. FIG. 14 is a sectional view taken along line CC of the bent portion 12 of the heating element 310. The heating device 300 of the present embodiment is different from the heating device 100 of the first embodiment in that the configuration of the current difference reducing unit 20 of the heating element 310 is different, and the other configurations are the same. The current difference reducing portion 20 of the heating element 310 of the present embodiment includes a thickness changing portion 24 in which the number of current paths is 8 and the thickness of the heating element 310 changes from the inside to the outside of the bending portion 12. .. By including the thickness changing portion 24, it is possible to reduce the bias of the current distribution in the width direction of the bent portion 12.

The thickness changing portion 24 of the present embodiment is formed from the bent portion 12 to the stretched portion 14. The thickness changing portion 24 of FIG. 13 is provided with eight current paths 12s, 12t, 12u, 12v, 12w, 12x, 12y, and 12z in order from the outside in the bending portion 12. That is, each inner radius r1 to r8 of the current paths 12s to 12z has a relationship of r1> r2> r3> r4> r5> r6> r7> r8. The current paths 12s to 12z may be separated from each other or may be in contact with adjacent current paths.

As shown in FIG. 14, the thicknesses D1 to D8 of the current paths 12s to 12z are set so that the difference between the respective resistance values becomes small. Specifically, the thicknesses D1 to D8 are set in the relationship of D1> D2> D3> D4> D5> D6> D7> D8. In this case, the current concentration inward can be relaxed.

Further, the widths W1 to W8 of the current paths 12s to 12z have a relationship of W1> W2 = W3 = W4 = W5 = W6 = W7 = W8. In particular, by making the width W1 of the outermost current path 12s larger than the width W2 of the adjacent current path 12t, the current flowing through the current path 12s can be increased, and the current concentration inward can be further relaxed.

The thickness changing portion 24 of FIG. 13 is provided with eight current paths 14s, 14t, 14u, 14v, 14w, 14x, 14y, and 14z in order from the outside in the stretching portion 14. The current paths 14s to 14z extend linearly from both ends of the current paths 12s to 12z. The width and thickness of the current paths 14s to 14z are formed to be equal to those of the current paths 12s to 12z. By providing the thickness changing portion 24 in the stretched portion 14, the resistance of the current path 14s to 14z is connected in series with the resistance of the current path 12s to 12z, and the difference in the combined resistance value can be reduced.

FIG. 15 is a diagram showing the temperature distribution of the heating element 310. As shown in this figure, the outermost temperature of the bent portion 12 is T3, which is higher than that of the first embodiment, and the current around this is increased. The innermost temperature of the bent portion 12 is T6, which is lower than that of the first embodiment, and the current concentration on this portion is further relaxed. That is, as compared with the first embodiment, the bias of the temperature distribution of the entire bent portion 12 is further alleviated.

In the description of FIG. 14, an example in which the current paths 12s to 12z are in contact with the adjacent current paths is shown, but the current paths 12s to 12z may be insulated from each other. For example, a separation unit may be provided between the current paths 12s to 12z.

For the heating element 310, the outer region where the current is low may be cut off. FIG. 16 is a plan view showing a heating element 310B in a state where the outer region 310c is excised from the heating element 310. It is considered that the heating element 310B exhibits the same temperature distribution as the heating element 310. By excising the region where the current is low, the material constituting the heating element can be saved.

The width and thickness of the current paths 12s to 12z and the current paths 14s to 14z can be set by simulation according to the desired characteristics. The above is the description of the heat generating device 300 of the third embodiment.

The outline of one aspect of the present invention is as follows. The heating device 100 according to an aspect of the present invention is a heating device including a thin-film heating element 10 having a bent portion 12, and the heating element 10 reduces the deviation of the current distribution in the width direction of the bent portion 12. It has a current difference reducing unit 20 of the above.

According to this aspect, it is possible to reduce the difference in resistance by changing the width and thickness according to the difference in the path length of the bent portion, suppress the current difference between the inside and outside, and alleviate the local current concentration. As a result, it is possible to reduce the bias of the temperature distribution of the heating element, suppress the abnormal heat generation in the inner region, and reduce the possibility of melting of the heated element and cracking of the printed wiring. This makes it easy to increase the starting current of the heating device and shorten the starting time.

The current difference reducing portion 20 may include the separating portions 18a and 18b that separate the bent portion 12 into a plurality of current paths 12a, 12b and 12c in the width direction. In this case, the difference in resistance can be reduced by changing the width and thickness of each of the plurality of separated current paths. By reducing the difference in resistance, the current concentration can be relaxed and the bias of the temperature distribution can be reduced.

The heating element 10 may have an extension portion 14 extending from the bending portion 12, and the separating portion may have extension portions 18c, 18d extending from the bending portion 12 to the extension portion 14. In this case, the current path of the stretched portion 14 is also separated and connected in series to the current paths 12a, 12b, and 12c, respectively. Therefore, the difference in resistance can be reduced to reduce the difference between the inside and outside of the current, and the bias of the temperature distribution can be further reduced. can.

The width of each of the plurality of current paths 12a, 12b, 12c may be set so that the difference between the resistance values of the plurality of current paths 12a, 12b, 12c is small. In this case, the difference between the inside and outside of the current becomes small, and the bias of the temperature distribution can be reduced.

The thickness of each of the plurality of current paths 12a, 12b, 12c may be set so that the difference between the resistance values of the plurality of current paths 12a, 12b, 12c is small. In this case, the difference between the inside and outside of the current becomes small, and the bias of the temperature distribution can be reduced.

The current difference reducing portion 20 may include a thickness changing portion 24 in which the thickness of the heating element 310 changes from the inside to the outside of the bending portion 12. In this case, the thickness changing portion 24 can reduce the bias of the current distribution and reduce the bias of the temperature distribution.

The heating element 10 may be formed by screen printing or dispenser printing. In this case, it is possible to easily form a current path having a different thickness for each portion of the heating element 10.

The heat generating device may be provided in housing equipment. In this case, it becomes easy to shorten the start-up time of heating of the housing equipment, and it is possible to provide the housing equipment that warms up quickly.

The above-mentioned housing equipment may be a floor, a toilet seat, glass or a window. In this case, it becomes easy to shorten the start-up time for heating the floor, toilet seat, glass or window. It can improve the comfort of the user in contact with the floor, toilet seat, glass or windows.

The above description has been made based on each embodiment of the present invention. It will be appreciated by those skilled in the art that these embodiments are exemplary and that various modifications and modifications are possible within the claims of the invention, and that such modifications and modifications are also within the claims of the present invention. It is about to be done. Therefore, the descriptions and drawings herein should be treated as exemplary rather than limiting.

Hereinafter, a modified example will be described. In the drawings and description of the modified examples, the same or equivalent components and members as those in the embodiment are designated by the same reference numerals. The description that overlaps with the embodiment will be omitted as appropriate, and the configuration different from the embodiment will be mainly described.

[Modification example]
In the description of each embodiment, an example in which the bent portion is curved in a curve is shown, but the present invention is not limited thereto. For example, the bent portion may have a shape that bends like a rectangular corner.

In the description of the first embodiment, an example in which the number of current paths (number of divisions) is 3, but the present invention is not limited thereto. The number of current paths may be a plurality, may be 2, or may be 4 or more.

In the description of the first embodiment, an example is shown in which the thicknesses Da, Db, and Dc of the current paths 12a, 12b, and 12c are equal to each other, but the present invention is not limited thereto. The thicknesses Da, Db, and Dc may be different from each other.

In the description of the third embodiment, an example in which the thicknesses D1 to D8 of each current path 12s to 12z changes stepwise is shown, but the present invention is not limited thereto. For example, the thickness of the heating element may continuously change from the inside to the outside of the bent portion.

In the description of the third embodiment, examples are shown in which the widths W2 to W8 of the current paths 12t to 12z are equal to each other, but the present invention is not limited thereto. For example, the widths W2 to W8 of the heating elements may be different from each other.

In the description of the third embodiment, an example in which the number of current paths is eight is shown, but the present invention is not limited thereto. The number of current paths may be a plurality, may be 7 or less, or may be 9 or more.

Each of the above-mentioned modifications has the same action / effect as that of each embodiment.

Any combination of each of the above-described embodiments and modifications is also useful as an embodiment of the present invention. The new embodiments resulting from the combination have the effects of each of the combined embodiments and variants.

The hatching attached to the drawing does not limit the material to which the hatching is attached.

10, 210, 310, 310B, 510 ... Heating element, 12 ... Bending part, 12a-12z ... Current path, 14 ... Stretching part, 14a-14z ... Current path, 18a, 18b ... Separation part, 18c, 18d ... extension part, 20 ... current difference reduction part, 24 ... thickness change part, 30 ... heated element, 100, 200, 300 ... heating device.

Claims (9)

A heat generating device including a thin film-shaped heat generating body having a bent portion.
The heating element has a current difference reducing portion for reducing the bias of the current distribution in the width direction of the bent portion.
The current difference reducing portion includes a separating portion that separates the bent portion into a plurality of current paths in the width direction.
The plurality of current paths include three current paths separated from each other in the width direction.
The three current paths are arranged in order from the outside to the inside, and each is a semicircular current path having a constant width.
A heat generating device characterized in that the width of each of the three current paths gradually narrows from the outside to the inside . The heat generating device according to claim 1, wherein the thickness of each of the three current paths is reduced in order from the widest to the narrowest of the three current paths. The heating element has a stretched portion extending from the bent portion and has a stretched portion.
The heat generating device according to claim 1 or 2, wherein the separating portion has an extending portion extending from the bent portion to the extending portion. The width of each of the three current paths is set according to any one of claims 1 to 3 , wherein the difference between the resistance values of the three current paths is set to be small. Heat generator. The thickness of each of the three current paths is set according to any one of claims 1 to 4, wherein the difference between the resistance values of the three current paths is set to be small. Heat generator. The heat generating device according to claim 1, wherein the current difference reducing portion includes a thickness changing portion in which the thickness of the heating element changes from the inside to the outside of the bending portion. The heating element according to any one of claims 1 to 6, wherein the heating element is formed by screen printing or dispenser printing. The heat generating device according to any one of claims 1 to 7, wherein the heat generating device is provided in a housing facility. The heat generating device according to claim 8, wherein the housing equipment is a floor, a toilet seat, glass, or a window.

Images