JP2011014268A - Planar heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar heating element having high safety and superior usability.SOLUTION: The planar heating element includes an electrically insulating base material 1, a pair of main electrodes 2a, 2b each being formed oppositely on both surfaces 1a, 1b of the electrically insulating base material 1 and connected to a power source, a plurality of branched electrodes 3a, 3b individually branched out from the main electrodes 2a, 2b; a plurality of connecting electrodes 4a, 4b further branching out from the branched electrodes 3a, 3b and disposed on an opposite position, and a plurality of resistors 5, structured to be electrically connected in between the connecting electrodes 4a, 4b. The planar heating element can be provided with high safety and superior usability.

Description

  The present invention relates to a planar heating element used for, for example, an electric floor heating panel, an electric carpet, etc., and in particular, a pattern configuration of an electrode and a resistor of a planar heating element in which electrodes and resistors are formed on the same surface. It is about.

  Conventionally, in this type of planar heating element, a power supply electrode is formed on one surface of an electrically insulating base material such as a polyester film, and a resistor is disposed in electrical connection with the power supply electrode.

  The power supply electrode is formed by branching a plurality of branch electrodes from a pair of main electrodes and further branching a plurality of connection electrodes from the branch electrodes, and is formed by printing a conductive silver polymer or the like.

  A plurality of resistors are provided independently on the corresponding connection electrodes, and are obtained by printing with PTC conductive ink.

  Therefore, when power is applied to the main electrode of the power supply electrode, each resistor is energized through the connection electrode to generate heat, and the region where the resistor is disposed is heated.

  The PTC conductive ink that forms the resistor is made by adding carbon black to an ethylene vinyl acetate copolymer resin and mixing it with a solvent (see, for example, Patent Document 1).

  The PTC characteristic means a resistance temperature characteristic in which the resistance value increases as the temperature rises, and when the temperature reaches a certain temperature, the resistance value rapidly increases. The heating region having the PTC characteristic has a self-temperature. It can be provided as a planar heating element having an adjusting function.

  In addition, as another planar heating element, it can be seen that strip electrodes are arranged on an electrically insulating substrate at intervals and a resistor film is divided between the strip electrodes (see, for example, Patent Document 2). ).

  On the other hand, on both surfaces of the electrically insulating substrate, a pair of main electrode portions, a branch electrode connected to the main electrode and provided to engage with each other in a comb-tooth shape, and a resistor disposed so as to cover the branch electrode, In some cases, the temperature unevenness of the planar heating element is improved by shifting the positions of the branch electrodes on both sides (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 3-129893 Japanese Utility Model Publication No. 57-186997 JP-A-8-64352

  In the conventional planar heating element, when the main electrode of the power supply electrode is disconnected, if the disconnection interval is extremely small, corona discharge may occur, which may cause dielectric breakdown.

  In particular, when the location near the base of the main electrode is disconnected, that is, when the location where the resistors overlap is disconnected, first, corona discharge occurs when the disconnection interval is extremely small, and the tip of the main electrode from the disconnected portion If there is more than the force necessary to generate electric power corresponding to the combined resistance of the heating region electrically connected to the part to generate sparks, then dielectric breakdown occurs and sparks occur.

  Since the heat generated by the spark is dissipated to the resistor that overlaps the disconnected portion and the periphery thereof, the disconnected portion of the main electrode does not evaporate, and the spark continues while the disconnection interval is kept extremely small. Furthermore, the resistor overlying the disconnection portion gradually changes due to the heat generated by the spark, and a bypass path connected with carbon is formed, and current flows.

  When the resistance value of the bypass path is a certain value, there arises a problem that abnormal heating occurs in the bypass path.

To solve this problem,
(1) In order not to generate a spark, the combined resistance of the heating region and the main electrode or the feeding electrode after the disconnection is increased.

(2) In order to disperse the heat generated by the spark or the heat generated in the bypass path,
(2-1) Affixing a metal foil (2-2) Widen the main electrode or feed electrode to a sufficient extent to dissipate heat (2-3) Increase the thickness of the main electrode or feed electrode to a sufficient extent to dissipate heat, etc. Conceivable.

  However, with regard to (1), in order to increase the combined resistance of the heating area after the disconnection and the main electrode or the feeding electrode, the number of heating areas is specifically reduced to reduce the heat generation area, or the heating area Although the distance between the two main electrodes sandwiching the electrode is widened, reducing the number of heating regions to reduce the heat generation area is the original function as a planar heating element. The purpose of generating heat is greatly diminished, and increasing the distance between the two feeding electrodes sandwiching the heating region also increases the resistance value of each heating region, and the amount of generated heat Since it is significantly reduced, it is not effective because it greatly impairs the purpose of increasing the temperature by generating heat, which is the original function of the planar heating element.

  Next, with regard to (2), sticking a metal foil to disperse the heat generated by the spark or the heat generated in the bypass path makes the planar heating element thick, heavy and hard, and high in cost. Problems such as becoming.

  When the width between the main electrodes or the power feeding electrodes is increased, the heat generation area is reduced, so that the purpose of generating heat in a planar manner, which is the original function of the planar heating element, is greatly impaired.

  Further, when the thickness of the main electrode or the feeding electrode is increased, the thickness of the sheet heating element is increased, and when the PTC conductive ink is printed on the feeding electrode, the feeding electrode and the electrically insulating substrate There is also a problem that a large step is formed between the power supply electrode and the heating region, a step crack (edge breakage) occurs at the boundary line between the power supply electrode and the heating region, the electrical connection is not established, and the heating region does not generate heat.

  In addition, since the heat generated by the spark is dissipated, the disconnection portion does not evaporate and the spark may continue, and in any case, it is not an effective solution.

Moreover, although the planar heating element disclosed in Patent Document 3 has improved temperature distribution as the planar heating element, the above-described spark problem cannot be solved.

  The present invention solves the above-described conventional problems, and even if the electrode to which the resistor is connected is disconnected, no spark is generated, abnormal overheating at the disconnected portion is prevented, and temperature rise is excellent. An object is to provide a planar heating element.

  In order to solve the above-mentioned problems, a pair of main electrodes formed on both sides of the insulating base material so as to face each other and connected to a power source, a plurality of branch electrodes individually branched from the main electrode, and the branch electrodes And a plurality of resistor elements formed by being electrically connected between the connection electrodes.

  Accordingly, even if the connection electrode to which the resistor is connected is disconnected, the spark does not continue, abnormal overheating at the disconnected portion is prevented, and a planar heating element excellent in temperature rise is provided. it can.

  According to the planar heating element of the present invention, the current flowing through each connection electrode is determined by the resistance value of the resistor, and if a resistance value that does not cause a spark even if the connection electrode is disconnected is set, the resistance of the resistor is altered. In addition, abnormal overheating due to carbonization can be prevented, and furthermore, since the resistors are provided on both surfaces of the electrically insulating base material, it is possible to provide a planar heating element that is excellent in temperature rise and easy to use.

The top view of the surface of the planar heating element in Embodiment 1 of this invention Main part enlarged plan view of the surface of the same heating element Top view of the back side of the same heating element The principal part enlarged plan view of the back of the same heating element Explanatory drawing which shows the connection state of the power supply and main electrode of the planar heating element in Embodiment 2 of this invention The top view of the surface of the planar heating element in Embodiment 3 of this invention Top view of the back side of the same heating element

  According to a first aspect of the present invention, an electrical insulating base material and at least a pair of power feeding electrodes formed on opposite sides of the electrical insulating base material and connected to a power source are individually branched from the power feeding electrodes. A plurality of branch electrodes and a plurality of connection electrodes that are further branched from the branch electrodes and disposed at opposing positions, and are electrically connected between the connection electrodes to provide a resistor. If the resistance value of the resistor determines the current value for the electrode, and if a resistance value is set that does not cause a spark even if the connection electrode is disconnected, abnormal overheating due to deterioration of the resistor or carbonization can be prevented, and electrical insulation Since the resistors are provided on both surfaces of the conductive base material, it is possible to provide a planar heating element that is excellent in temperature rise and easy to use.

  The second invention is configured such that the resistor on the surface of the planar heating element of the first invention is provided at a position facing the plurality of resistors on the back surface facing each other through the electrically insulating substrate, Since the mutual non-heat generating parts are complemented, a planar heating element with little temperature unevenness can be provided.

3rd invention sets it as the structure which controls separately the power supply connected to the surface side main electrode and the power supply connected to a back surface side main electrode of the planar heating element of 1st invention. By controlling the power supplied to the sheet heating element as required, fine temperature control becomes possible, and a sheet heating element contributing to further improvement in usability and energy saving can be provided.

  According to a fourth aspect of the invention, the main electrodes on both sides of the planar heating element of the first or second invention are arranged at positions facing each other through the electrically insulating base material, and the power is supplied to the main electrodes on both sides from the same position. The power supply to the power supply electrodes on both sides can be simplified and an inexpensive sheet heating element can be provided.

  According to a fifth invention, in any one of the first to third inventions, the power supply to the power supply electrodes on both surfaces of the sheet heating element is supplied from the opposite side to the front side and the back side. In order to compensate for the difference in heat generated between the power supply side and the terminal side due to the voltage drop due to the line resistance of the main electrode, it is possible to provide a planar heating element with little temperature unevenness.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiments do not limit the present invention.

(Embodiment 1)
1 and 2, on the surface 1a of the electrically insulating substrate 1 made of a polyester film or the like, a pair of main electrodes 2a and 2b and a pair of main electrodes 2a and 2b, which are spaced from each other, are connected to the other electrode. An electrode comprising a plurality of branch electrodes 3a and 3b branched individually and a plurality of connection electrodes 4a and 4b further branched from the branch electrodes 3a and 3b is formed by printing and drying a silver paste. .

  A large number of resistors 5a are independently formed between the corresponding connection electrodes 4a and 4b of the adjacent branch electrodes 3a and 3b.

  In addition, the back surface 1b of the electrically insulating base material 1 is also provided with a pair of main electrodes 2c and 2d spaced apart from each other, and a plurality of individual branches branched from the main electrodes 2c and 2d toward the other electrode. An electrode composed of branch electrodes 3c and 3d and a plurality of connection electrodes 4c and 4d further branched from the branch electrodes 3c and 3d is configured by printing and drying silver paste.

  A large number of resistors 5b are independently formed between the corresponding connection electrodes 4c and 4d of the adjacent branch electrodes 3c and 3d.

  The front and back resistors 5a and 5b are positioned so as to face the overlapping positions, but are shifted in the vertical and horizontal directions.

  A power source 6a is connected between the main electrodes 2a and 2b on the front side, and a power source 6b is also connected independently between the main electrodes 2c and 2d on the back side, and power supply is controlled by the power control means 7a and 7b. It is made to do.

  Resistors 5a and 5b are polymer resistor inks in which a polymer resistor material in which carbon is kneaded into a resin is dissolved in a solvent, or in particular, a polymer resistor material in which carbon is kneaded in a crystalline resin is dissolved in a solvent. Is formed by printing and drying.

  Next, the operation and action will be described.

First, as a normal operation state, when the power supply control means 7a and 7b are in the ON state, the current flowing through the surface 1a of the electrically insulating substrate 1 by the power supply 6a connected between the power supply electrodes 2a and 2b is the main electrode 2a. → branch electrode 3a → connection electrode 4a → resistor 5a → connection electrode 4b → branch electrode 3b → main electrode 2b In this order, if the power supply is an alternating current, naturally the flow direction opposite to this flow direction is generated alternately. The body 5a generates heat.

  Similarly, the current flowing on the back surface 1b side of the electrically insulating substrate 1 also flows in the order of main electrode 2c → branch electrode 3c → connection electrode 4c → resistor 5b → connection electrode 4d → branch electrode 3d → main electrode 2d. The body 5b generates heat.

  On the other hand, when the connection electrode 4a or 4b is disconnected on the surface 1a side of the electrically insulating substrate 1, the connection electrode 4a or 4b originally has a circuit configuration for supplying power using individual resistors as loads. If each resistance value is set to the high resistance side in advance at a level where no spark energy is generated even if the electrode 4a or 4b is disconnected, no spark is generated, and abnormalities due to the change in the resistance or carbonization of the resistor at the disconnection point Overheating can be prevented.

  Even when the connection electrode 4c or 4d is disconnected on the back surface 1b side of the electrically insulating substrate 1, abnormal heating can be similarly prevented.

  In addition, when a plurality of resistors 5a and 5b disposed on both surfaces of the electrically insulating substrate 1 are energized at the same time, the amount of heat generated per unit area of the electrically insulating substrate 1 is equal to that of the resistors 5a and 5b. If so, the temperature rise is almost double as compared with the case where the resistor is disposed only on one side, and the temperature rise is excellent.

  Furthermore, since the resistors 5a5b on both sides are arranged so as to be displaced from each other in the vertical and horizontal directions, non-heat generation regions generated around the resistors are complemented to suppress temperature unevenness.

  Further, by independently controlling the power applied to the front-side resistor 5a and the back-side resistor 5b, it becomes possible to perform both-sided simultaneous heating, single-sided heating, or intermittent heating of each, and if necessary, a sheet shape Since the surface temperature of the heating element can be variably controlled, an easy-to-use planar heating element can be provided.

(Embodiment 2)
FIG. 5 shows the second embodiment. The difference from the first embodiment is that the main electrodes 2a and 2b on the front surface 1a side and the main electrodes 2c and 2d on the back surface 1b side are placed with the insulating base material 1 in between. The main electrodes 2a and 2c and 2b and 2d are electrically connected via a conductor 8 such as a rivet and connected to a common power source 6 and power source control means 7.

By configuring in this way, it is not necessary to wire the connection to the power source 6 individually for each side, and an inexpensive planar heating element can be provided.
(Embodiment 3)
6 and 7 show the third embodiment. In addition, the same code | symbol is attached | subjected to the component which performs operation | use for FIG.1, 3, and the thing of Embodiment 1 is used for the concrete description.

  The difference from the first embodiment is that the power connection position to the main electrodes 2a and 2b on the front surface 1a side of the electrically insulating substrate 1 and the power connection position to the main electrodes 2c and 2d on the back surface 1b side are This is provided on the opposite side to the insulating substrate 1.

  By disposing the power supply positions for the main electrodes 2a, 2b and 2c, 2d on the opposite sides, heat generation unevenness caused by a voltage drop generated on the terminal side with respect to the power supply side due to the passage resistance of these main electrodes And the back surface, and as a result, heating unevenness can be suppressed.

As described above, the sheet heating element according to the present invention prevents abnormal overheating at the disconnection point even if a spark occurs even if the electrode to which the resistor is connected is disconnected, and increases the temperature rise. Since an excellent planar heating element can be provided, the invention can be applied not only to heating products such as floor heating panels and electric carpets but also to all planar heating elements in which a heating part is formed in a planar shape.

DESCRIPTION OF SYMBOLS 1 Electric insulating base material 1a Front surface 1b Back surface 2a, 2b, 2c, 2d Main electrode 3a, 3b, 3c, 3d Branch electrode 4a, 4b, 4c, 4d Connection electrode 5a, 5b Resistor 6, 6a, 6b Power supply

Claims (5)

An electrically insulating substrate, a pair of main electrodes formed opposite to both the front and back surfaces of the electrically insulating substrate, connected to a power source, a plurality of branch electrodes individually branched from the feeding electrode, and the A planar heating element comprising: an electrode comprising a plurality of connection electrodes that are further branched from the branch electrode and disposed at opposing positions; and a plurality of resistors formed by electrical connection between the connection electrodes. The planar heating element according to claim 1, wherein the front-side resistor and the back-side resistor are positioned to face each other. The planar heating element according to claim 1, wherein the power source connected to the front-side main electrode and the power source connected to the back-side main electrode are controlled independently of each other. The planar heating element according to claim 1 or 2, wherein the main electrodes on both sides are disposed at positions facing each other through the electrically insulating base material, and power is supplied to the main electrodes on both sides from the same position. The planar heating element according to any one of claims 1 to 3, wherein power is supplied to the main electrodes on both sides from opposite sides of the front side and the back side.