JPH11111433A - Panel-type heat generator dealing with low electromagnetic wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the structure simple and compact and lower the electromagnetic waves by forming a resistance heat generator on the surface of an insulating substrate by coating or printing, sticking a metal foil to the rear side of the insulating substrate, and constituting the structure as to run electric current in the direction reverse to the direction in which electric current flows in the resistance heat generator. SOLUTION: In this heat generator, an electric current flows in an aluminum foil 3 in the direction opposite to the direction in which an electric current flows in the resistive heat generator 2. Magnetic fields are generated in the circumferences of conductors due to the flow of the electric current and in the case electric current flows in reverse directions in paralleled conductors such as the resistance heat generator 2 and the aluminum foil 3, the magnetic fields generated mutually reverse directions in the front side and the rear side are mutually canceled. Consequently, the total intensity of the electromagnetic waves is lowered and the aluminum foil 3 with high thermal conductivity works as to eliminate uneven heat distribution in an insulating substrate 1 and as a result, the heat in the insulating substrate and the resistance heat generator 2 is made even. This panel type heat generator is constituted of an insulating substrate 1, a resistance heat generator 2, an aluminum foil 3, a copper foil 4, an insulating film 5, a temperature controller 6, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar heating element capable of coping with low electromagnetic waves, and more particularly, to an electric heating device for home or business use (for example, electric carpet, electric blanket, panel heater, etc.). The present invention relates to a low-electromagnetic-wave-compatible planar heating element used in an electric heating appliance such as a hot plate or a hot plate.

[0002]

2. Description of the Related Art In general, a sheet heating element used in an electric heating device such as an electric carpet is constituted by a linear heating element such as a nichrome wire heater, but other types of sheet heating elements are used. The body has also become known in recent years. For example, a planar heating element formed by coating or printing a resistance heating element of an Ag-based or carbon-based on an insulating base material has already been developed.

[0003]

However, the conventional planar heating element has a problem that an electromagnetic wave is generated when an alternating current flows. A magnetic field is created around a current-carrying conductor, and when the current undulates, a magnetic field of the same frequency is generated around it, resulting in a wave containing both electric and magnetic fields.
(Ie, electromagnetic waves).

[0004] Among the large electromagnetic waves, there is a possibility that noises may be given to video / audio electric products (so-called AV products), precision equipment, and the like. In addition, there are reports that there are concerns about the effects of electromagnetic waves on the human body. Therefore, it is desired to reduce electromagnetic waves particularly for products that touch the human body, such as electric carpets and electric blankets. However, it is difficult to block electromagnetic waves from an electric heater with a large heating area such as an electric carpet.

[0005] The applicant of the present invention has previously filed an application concerning measures to reduce electromagnetic waves of a sheet heating element (Japanese Patent Application No. 8-155458), but problems such as manufacturing defects and costs have been sufficiently solved. Not really. The present invention has been made in view of such a situation, and has an object to provide a low-electromagnetic-wave-compatible planar heating element capable of reducing electromagnetic waves while having a simple and compact structure suitable for manufacturing. Aim.

[0006]

According to a first aspect of the present invention, there is provided a planar heating element for low electromagnetic waves, wherein a resistance heating element is formed on a surface of an insulating substrate by coating or printing. Body, a metal foil is attached to the back surface of the insulating base material, and a current in a direction opposite to a direction of a current flowing through the resistance heating element is configured to flow through the metal foil. Features.

According to a second aspect of the present invention, there is provided a planar heating element for low electromagnetic waves,
In the configuration of the first aspect, the resistance heating element and the metal foil are electrically connected in series.

A third aspect of the invention is a low-electromagnetic-wave-compatible planar heating element,
In the configuration of the second aspect of the present invention, by folding the tape for a metal foil electrode with a conductive adhesive from the front side to the back side at the end of the insulating base material, and attaching the tape to the resistance heating element and the metal foil, The resistance heating element and the metal foil are electrically connected in series.

According to a fourth aspect of the present invention, there is provided a planar heating element adapted to a low electromagnetic wave,
In the structure of the second or third invention, the pattern of the resistance heating element is formed in a stripe shape or an S-shape.

According to a fifth aspect of the present invention, there is provided a planar heating element for low electromagnetic waves,
In the configuration of the second invention, the metal foil is attached in a state where the metal foil protrudes from the back surface of the insulating base material, and the metal foil electrode tape with a conductive adhesive is not folded back at an end of the insulating base material. It is characterized in that the resistance heating element and the metal foil are electrically connected in series by sticking from the protruding portion of the foil to a part of the resistance heating element.

According to a sixth aspect of the present invention, there is provided a low-electromagnetic-wave-compatible planar heating element,
In the configuration of the second or third invention, a through hole is provided in a part of the insulating base material, and the terminal on the metal foil side is formed from the back surface side to the front surface side of the insulating base material through the through hole. It is characterized by being taken out.

According to a seventh aspect of the present invention, there is provided a planar heating element for low electromagnetic waves,
In the configuration of the second or third invention, a part of an end portion of the insulating base material is processed into a convex shape, and a metal foil electrode for the resistance heating element is provided on a surface side of the convex processed portion. A part of the metal foil is arranged on the back side, and a flat resectorable connector is connected to the protruding portion.

According to an eighth aspect of the present invention, there is provided a planar heating element for low electromagnetic waves,
In the configuration of the seventh aspect, a reinforcing plate is laminated on the convex processed portion.

According to a ninth aspect of the present invention, there is provided a planar heating element for low electromagnetic waves,
In the configuration of the first or second aspect of the invention, the resistance heating element is formed on a substrate obtained by laminating the metal foil on the insulating substrate in advance.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a planar heating element for low electromagnetic waves according to the present invention. In addition,
The same reference numerals are given to the same portions or corresponding portions in the embodiments, and the repeated description will be appropriately omitted.

<< First Embodiment (FIGS. 1 and 2) >> FIG.
FIG. 1 shows a schematic longitudinal sectional structure of a low-electromagnetic-wave-compatible planar heating element according to the first embodiment. The sheet heating element is composed of an insulating base material 1, a resistance heating element 2, an aluminum foil 3, a copper foil (a tape for a metal foil electrode with a conductive adhesive) 4, an insulating film (a laminated film for an overcoat) 5, and a temperature controller 6. , A phase converter 7 and the like. Insulating substrate 1 is PET
(polyethylene terephthalate) film, but is not limited to this. As the insulating base material 1, a base material made of an insulating material according to the use of the sheet heating element may be used.

On the surface of the insulating substrate 1, a resistance heating element 2 is printed in a rectangular shape. The resistance heating element 2 is made of an Ag-based or carbon-based resistance heating material, and is formed by screen-printing the conductive paste on substantially the entire surface (that is, one surface) of the insulating base material 1. Note that the resistance heating element 2 may be formed by another printing method or coating.

On the other hand, the same rectangular aluminum foil 3 as the resistance heating element 2 is attached to the back surface of the insulating base material 1 (ie, the surface opposite to the surface on which the insulating base material 1 is formed). . The aluminum foil 3 is suitable for this planar heating element in that it is a low-cost conductive material having excellent thermal conductivity.
In other words, any other type of metal foil or the like can be used instead of the aluminum foil 3 as long as it is a foil-like sheet made of a conductive material having good thermal conductivity, but does not need to function as a resistance heating element. Therefore, inexpensive aluminum foil 3 is suitable.

As shown in FIG. 1, this planar heating element is configured such that a current in a direction opposite to the direction of the current flowing through the resistance heating element 2 flows through the aluminum foil 3. Since a magnetic field is generated around the current-carrying conductor in the right-handed screw direction in which the current flows, when a reverse current flows between the parallel heating wires, such as the resistance heating element 2 and the aluminum foil 3, Act so that the magnetic fields generated in opposite directions cancel each other. That is, the magnetic fields generated in the opposite directions on the front surface and the back surface of the insulating base material 1 cancel each other out (so-called demagnetizing effect). As a result, the total electromagnetic wave is reduced, and an electromagnetic wave reduction effect is obtained. Further, since the aluminum foil 3 having good thermal conductivity acts to eliminate the temperature unevenness of the insulating base 1, the temperatures of the insulating base 1 and the resistance heating element 2 are made uniform, so that a so-called soaking effect is obtained. Can be Since the intensity of the generated magnetic field is proportional to the magnitude of the flowing current, it is desirable that the magnitude of the current flowing through the resistance heating element 2 and the magnitude of the current flowing through the aluminum foil 3 be equal.

FIG. 2 is a graph showing the relationship between the current and the strength of the magnetic field (that is, the magnitude of the generated electromagnetic wave) in the first embodiment. In this graph, a current of the same magnitude is applied to the resistance heating element 2 and the aluminum foil 3, and the current (A) and the strength of the magnetic field (mG) at that time are measured using an electromagnetic wave environment measuring device (Micro ELF manufactured by Arnu Medical Instruments Co., Ltd.) ) Shows the measurement result (measurement distance: 0 mm). In the same figure, Δ: a case where current is applied to both the resistance heating element 2 and the aluminum foil 3 (first embodiment); ◆: a case where current is applied only to the resistance heating element 2 (comparative example) .

As can be seen from the graph of FIG. 2, when a current is applied to the aluminum foil 3, the intensity of the magnetic field is reduced to 1/4, and a clear demagnetizing effect is observed. In general, the temperature near the center of the resistance heating element printed on one surface tends to locally increase, but in the first embodiment, the temperature of the insulating base material 1 is increased due to the good thermal conductivity of the aluminum foil 3. As a result of eliminating unevenness,
A soaking effect was observed.

In the first embodiment, the resistance heating element 2 is printed on the surface of the insulating base 1, but a linear heating element such as a nichrome wire heater is mounted on the surface of the insulating base 1. Even in the pasted configuration, the same effect as described above can be obtained by pasting the aluminum foil 3 on the back surface of the insulating base material 1. In the first embodiment, the insulating base 1
Aluminum foil 3 is stuck on the back surface of the metal foil. However, even when a film having the same properties as the metal foil is formed by evaporating a metal such as aluminum, the same effect as above can be obtained. Can be.

The production of the sheet heating element according to the first embodiment mainly includes the following steps (1) to (3). (1) A step of forming the resistance heating element 2 on the surface of the insulating substrate 1 by coating or printing. (2) A step of attaching the aluminum foil 3 to the back surface of the insulating base 1. (3) A step of laminating with the insulating film 5.

The production may be performed in the order of steps (1) → (2) → (3), or the production may be performed in the order of steps (2) → (1) → (3).
Since a base material in which a metal foil such as an aluminum foil 3 is preliminarily laminated on an insulating base material 1 such as a PET film is already on the market, the latter for forming the resistance heating element 2 on such a commercially available laminate. If the manufacturing method is adopted, the process (2)
Can be omitted, so that the manufacturing process is simplified and the manufacturing time is shortened, so that the manufacture of the planar heating element can be performed smoothly.

<< Second Embodiment (FIG. 3) >> FIG.
1 shows a schematic vertical cross-sectional structure of a low-electromagnetic-wave-compatible planar heating element according to the embodiment. The feature of this sheet heating element is that a copper foil (metal foil electrode tape with a conductive adhesive) 4 is folded from the front side to the back side at the end of the insulating base material 1 to form the resistance heating element 2 and the aluminum foil 3. The point is that the resistance heating element 2 and the aluminum foil 3 are electrically connected in series by pasting.

Since the resistance heating element 2 on the front side of the insulating substrate 1 and the aluminum foil 3 on the back side are electrically connected in series, a current in a direction opposite to the direction of the current flowing through the resistance heating element 2 is generated. It will flow on the aluminum foil 3. Therefore, the same effect as in the first embodiment can be obtained without using the phase conversion device 7. Actually, when a voltage was applied between the resistance heating element 2 and the aluminum foil 3 to cause a current to flow to generate heat, the same demagnetizing effect and soaking effect as in the first embodiment were obtained. In addition, since the electrical connection is made simple and compact by the configuration in which the resistance heating element 2 and the aluminum foil 3 are short-circuited by the copper foil 4, reduction of electromagnetic waves can be achieved with a compact design.

<< Third Embodiment (FIG. 4) >> FIG.
1 shows a schematic plan structure of a low-electromagnetic-wave-compatible planar heating element according to an embodiment of the present invention. The feature of this planar heating element is that the pattern of the resistance heating element 2 is formed in a stripe shape. The structure is the same as that of the second embodiment except that the resistance heating element 2 is patterned in a stripe shape (each stripe is perpendicular to the copper foil 4 constituting the electrode). Therefore, the same effect as in the second embodiment can be obtained. Further, since the pattern of the resistance heating element 2 is formed in a stripe shape, the resistance can be easily adjusted. Actually, when a current was applied by applying a voltage between the resistance heating element 2 and the aluminum foil 3 to generate heat, the size of the electromagnetic wave was reduced to about 1/4 as compared with a case where no current was applied to the aluminum foil 3. Thus, the same demagnetizing effect and soaking effect as in the first embodiment were obtained.

<< Fourth Embodiment (FIG. 5) >> FIG.
1 shows a schematic plan structure of a low-electromagnetic-wave-compatible planar heating element according to an embodiment of the present invention. The characteristic of this planar heating element is that the pattern of the resistance heating element 2 is formed in an S shape. Except that the resistance heating element 2 is patterned in an S-shape,
Since the configuration is the same as that of the second embodiment, the same effect as that of the second embodiment can be obtained. In addition, the resistance heating element 2
Is formed in an S-shape, the resistance can be easily adjusted.

As shown in FIG. 5, when the pattern of the resistance heating element 2 is S-shaped, each line of the resistance heating element 2 becomes long, and at the same time, the electromagnetic waves are partially strengthened.
However, the total electromagnetic wave is weakened for the entire sheet heating element. When a voltage was actually applied between the resistance heating element 2 and the aluminum foil 3 to cause an electric current to flow,
The magnitude of the electromagnetic wave was reduced to about 1/2 as compared with the case where no current was passed through the aluminum foil 3. If the aluminum foil 3 is also patterned in the same manner as the resistance heating element 2, the electromagnetic wave is not partially strengthened, so that the same demagnetizing effect as in the third embodiment can be obtained. However, in that case, the soaking effect may be reduced.

<< Fifth Embodiment (FIG. 6) >> FIG.
1 shows a schematic vertical cross-sectional structure of a low-electromagnetic-wave-compatible planar heating element according to the embodiment. The feature of this sheet heating element is that the aluminum foil 3 is attached in a state of protruding from the back surface of the insulating base material 1, and the copper foil 3
By attaching (tape for metal foil electrode with conductor adhesive) 4 from the protruding portion of the aluminum foil 3 to a part of the resistance heating element 2 without being folded at the end of the insulating base material 1,
The point is that the resistance heating element 2 and the aluminum foil 3 are electrically connected in series.

Since the area of the aluminum foil 3 is larger than that of the insulating base material 1, when the copper foil 4 is applied from the aluminum foil 3 protruding from the back surface of the insulating base material 1 to a part of the resistance heating element 2, Even if the copper foil 4 is not folded, the resistance heating element 2 and the aluminum foil 3 can be short-circuited. Therefore, the step of attaching the copper foil 4 can be performed easily and smoothly, and the same demagnetizing effect and soaking effect as in the first embodiment can be obtained more easily than in the second embodiment. it can.

<< Sixth Embodiment (FIG. 7) >> FIG.
1 shows a schematic vertical cross-sectional structure of a low-electromagnetic-wave-compatible planar heating element according to the embodiment. A feature of this planar heating element is that a through hole 8 is provided in a part of the insulating base material 1, and the terminal on the aluminum foil 3 side is passed through the through hole 8 from the back side to the front side of the insulating base material 1. It is in the point that has been taken out.

As shown in FIG. 7, a copper foil 4 for electrodes attached to an aluminum foil 3 has
A lead wire is soldered from the (resistor heating element 2 side) through the through hole 8, and the lead wire is insulated by the insulating film 5 (or insulating tape). Has been taken out. By taking out the terminal on the aluminum foil 3 side through the through hole 8 formed in the insulating base material 1 in this manner, the structure is more compact than in the second embodiment and the like, and the demagnetizing effect is the same as in the second embodiment. And a soaking effect can be obtained. Note that a tape for a metal foil electrode with a conductive adhesive may be used instead of the lead wire.

<< Seventh Embodiment (FIGS. 8 and 9) >>
FIG. 9 shows a schematic planar structure and a schematic longitudinal sectional structure of a main part of a low-electromagnetic-wave-compatible planar heating element according to the seventh embodiment. A feature of this planar heating element is that a part of an end portion of the insulating base material 1 is processed in a convex shape, and a copper foil constituting an electrode for the resistance heating element 2 is formed on a surface side of the convex processed portion 1a. 4. A part of the aluminum foil 3 is arranged on the back surface side, and the point is that a planar resectorable connector 9 is connected to the convex processing portion 1a. Not only can the same demagnetizing effect and heat equalizing effect as in the second embodiment be obtained, but also the convex processed portion 1a
Has a structure that can be connected to the resectorable connector 9, so that power can be supplied more easily and safely than in the second embodiment and the like.

<< Eighth Embodiment (FIG. 10) >> FIG.
16 shows a schematic vertical cross-sectional structure of a main part of a low-electromagnetic-wave-compatible planar heating element according to an eighth embodiment. The feature of this planar heating element is that the reinforcing plate 10 is laminated on the convex processed portion 1a. As described above, by providing the reinforcing plate 10 at the connection portion with the receptacle connector 9, it is possible to cope with a thinner insulating base material 1. The reinforcing plate 10 may be a base material having strength as required and having a thickness capable of being insulated.

[0036]

As described above, the first to ninth inventions have a simple and compact structure suitable for manufacturing, in which a metal foil is attached to the back surface of an insulating base material. Since the current in the direction opposite to the direction of the current flowing through the resistance heating element flows through the metal foil, the magnetic fields in the opposite directions cancel each other out, thereby reducing electromagnetic waves. Moreover, since the metal foil acts to eliminate the temperature unevenness of the insulating base material and the resistance heating element, a soaking effect can be obtained.

According to the second to ninth aspects, since the resistance heating element and the metal foil are electrically connected in series, the effect of reducing electromagnetic waves and achieving a soaking effect can be obtained with a simple configuration. be able to. According to the third, fourth, sixth to eighth inventions,
Since the series connection is performed by the tape for the metal foil electrode with the conductive adhesive, electromagnetic waves can be reduced with a simple and compact design. According to the fourth invention,
Since the pattern of the resistance heating element is formed in a stripe or S-shape, resistance adjustment is easy. Further, since the temperature of the insulating base material is made uniform by the metal foil, it is possible to generate heat all over the surface regardless of the pattern of the resistance heating element.

According to the fifth aspect of the present invention, the resistance heating element and the metal foil can be short-circuited without folding the tape for the metal foil electrode with the conductive adhesive, so that the process of attaching the metal foil is simplified. It can be done smoothly. According to the sixth aspect, since the terminal on the metal foil side is taken out from the resistance heating element side through the through hole provided in a part of the insulating base material, the sheet heating element can be made more compact. it can.

According to the seventh and eighth aspects of the present invention, since the protruding portion of the insulating base is connected to the planar resizable connector, it is simple and safe despite its compact structure. Power can be supplied. further,
According to the eighth aspect, since the reinforcing plate is laminated on the convex processed portion, it is possible to cope with a thinner insulating base material. Further, according to the ninth aspect, since the metal foil is preliminarily laminated on the insulating base material, one step can be omitted. Therefore, the manufacturing process is simplified and the manufacturing time is shortened, so that the manufacturing of the planar heating element can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is an end view showing a schematic longitudinal sectional structure of a first embodiment.

FIG. 2 is a graph showing a relationship between a current and an electromagnetic wave in the first embodiment.

FIG. 3 is an end view showing a schematic longitudinal sectional structure of a second embodiment.

FIG. 4 is a plan view showing a schematic structure of a third embodiment.

FIG. 5 is a plan view showing a schematic structure of a fourth embodiment.

FIG. 6 is an end view showing a schematic longitudinal sectional structure of a fifth embodiment.

FIG. 7 is an end view showing a schematic longitudinal sectional structure of a sixth embodiment.

FIG. 8 is a plan view showing a schematic structure of a seventh embodiment.

FIG. 9 is an end view showing a schematic longitudinal sectional structure of a main part of a seventh embodiment.

FIG. 10 is an end view showing a schematic longitudinal sectional structure of a main part of an eighth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Insulation base material 1a Convex processed part 2 Resistance heating element 3 Aluminum foil (metal foil) 4 Copper foil (metal foil electrode tape with conductor adhesive) 5 Insulating film (laminated film for overcoat) 6 Temperature controller 7 Phase conversion Apparatus 8 Through hole 9 Resectorable connector 10 Reinforcement plate

Claims (9)

[Claims] 1. A planar heating element in which a resistance heating element is formed by coating or printing on the surface of an insulating base material, wherein a metal foil is attached to the back surface of the insulating base material, Characterized in that a current in a direction opposite to a direction of a current flowing through the metal foil flows through the metal foil. 2. The sheet heating element according to claim 1, wherein said resistance heating element and said metal foil are electrically connected in series. 3. The planar heating element according to claim 2, wherein the metal foil electrode tape with a conductive adhesive is folded from the front side to the rear side at the end of the insulating base material, and the resistance heating element and the metal foil are folded. Wherein the resistance heating element and the metal foil are electrically connected in series by being attached to the heating element. 4. The planar heating element according to claim 2, wherein a pattern of said resistance heating element is formed in a stripe or S-shape. . 5. The planar heating element according to claim 2, wherein the metal foil is pasted on the insulating substrate so as to protrude from a back surface of the insulating substrate, and a tape for a metal foil electrode with a conductive adhesive is attached to an end of the insulating substrate. A low-electromagnetic-wave-compatible surface, wherein the resistance heating element and the metal foil are electrically connected in series by being applied from the protruding portion of the metal foil to a part of the resistance heating element without being folded back at the portion. Heating element. 6. The planar heating element according to claim 2, wherein a through hole is provided in a part of the insulating base material, and the insulating base material passes from the back surface to the front surface through the through hole. And the terminal on the metal foil side being taken out. 7. The planar heating element according to claim 2, wherein a part of an end portion of the insulating base is processed into a convex shape, and the surface of the convex processed portion has the resistance. A metal foil electrode for a heating element, a part of the metal foil is arranged on the back side, and a flat resectorable connector is connected to the convex processing portion, wherein Heating element. 8. The planar heating element for low electromagnetic waves according to claim 7, wherein a reinforcing plate is laminated on the protruded portion. 9. The planar heating element according to claim 1, wherein the resistance heating element is formed on a substrate obtained by laminating the metal foil on the insulating substrate in advance. Low-electromagnetic-wave-compatible planar heating element.