JP5407604B2 - Planar heating element and manufacturing method thereof - Google Patents

Description

  The present invention relates to a planar heating element used for, for example, an electric floor heating panel and an electric carpet, and more particularly to an electrode configuration of a planar heating element in which electrodes and resistors are formed on the same plane.

  Conventionally, this type of planar heating element has an electrically insulating substrate such as a polyester film formed of a pair of conductive bus bars and an electrode composed of comb-shaped conductor paths branched in parallel from each of the conductive bus bars. It was formed by printing on it and printed with a resistor so as to cover the conductor passage.

  This resistor is formed by printing and drying PTC conductive ink. As a result, a heating region is set between the conductor paths.

  The PTC conductive ink forming the heating region is obtained by adding carbon black to an ethylene vinyl acetate copolymer resin and mixing it with a solvent to form an ink (for example, see 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. A planar heating element having an adjusting function can be provided.

Japanese Patent Laid-Open No. 3-129893

  In the conventional sheet heating element, a step is generated at the boundary between the conductor passage and the electrically insulating substrate. Normally, when PTC conductive ink is printed, the PTC conductive ink is electrically connected to the conductor passage and the electrically insulating substrate. The resistor enters the boundary between the insulating substrate, that is, the edge portion of the conductor passage by its own weight, and is dried to physically and electrically connect the resistor and the conductor passage.

  However, depending on variations in physical properties due to the manufacturing process of the PTC conductive ink and variations in printing conditions in the printing process, as shown in FIG. 8, the resistor 101 is connected to the conductor paths 102a and 102b by printing and drying the PTC conductive ink. The film of the resistor 101 floats in the air due to the step of the edge portion 103, and the edge portion 103 serves as a cutter and cannot maintain the film formation. A tear 104 would occur.

  Since the resistor 101 falls on the electrically insulating substrate 105 by its own weight as it is, the resistor 101 and the conductor passages 102a and 102b are not physically and electrically connected, and the portion where the tear 104 of the 101 is generated generates heat. In addition, when the tear 104 is large and the connection portion with the conductor passages 102a and 102b is small, there is a problem that current concentrates on the portion and abnormal heat generation occurs.

  In order to solve this problem, it is conceivable that the printed film thickness of the conductor passages 102a and 102b is reduced to reduce the step difference between the electrically insulating substrate 105, but the conductor passages 102a and 102b are reduced in thickness. Then, the resistance value of itself increases, and a predetermined current does not flow through the resistor 101 so that sufficient heat generation cannot be obtained, or conversely, the conductor paths 102a and 102b themselves generate heat. There was a problem.

  The present invention solves the above-mentioned conventional problems, and provides a planar heating element in which a resistor generates heat even when there is a variation in physical properties or a variation in printing conditions due to the production process of PTC conductive ink. With the goal.

In order to achieve the above object, the present invention provides an electrically insulating substrate, a pair of main electrodes formed by printing so as to face the electrically insulating substrate, and a connection branched from these main electrodes in a comb shape. The electrode comprises an electrode and a polymer resistor printed so as to overlap the connection electrode, and at least the connection electrode covered with the polymer resistor has a substantially triangular cross-sectional shape .

  Therefore, when the polymer resistor ink is printed so as to cover the connection electrode so as to constitute the polymer resistor, the generation of the tear can be prevented.

According to the planar heating element of the present invention, the cross-sectional shape of the connection electrode covered with at least the polymer resistor is made substantially triangular , so that no tearing occurs in the polymer resistor, and therefore, uniform Can generate a large amount of heat.

The top view which shows the structure of the planar heating element in Embodiment 1 of this invention An enlarged cross-sectional view of the main part of the same heating element Partial enlarged sectional view of the electrode printing plate of the same heating element Explanation of electrode preparation for coplanar heating element The principal part expanded sectional view of the planar heating element in Embodiment 2 of this invention Partial enlarged sectional view of the electrode printing plate of the same heating element Explanation of electrode preparation for coplanar heating element Main section enlarged sectional view of a conventional sheet heating element

The present invention provides an electrically insulating substrate, a pair of main electrodes formed on the substrate so as to face each other, a connection electrode extending in a comb shape from the main electrode, and overlapping the connection electrode A polymer resistor formed and electrically coupled, and at least the connection electrode covered with the polymer resistor has a substantially triangular cross-sectional shape to form a polymer resistor Thus, when the polymer resistor ink is printed so as to cover the connection electrode as much as possible, the tearing is prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
1 and 2, a sheet heating element 1 is configured by forming an electrode 3 and a polymer resistor 4 on an electrically insulating substrate 2 such as a polyester film by a printing method.

  The electrode 3 is composed of main electrodes 3a and 3b and connection electrodes 3c and 3d branched in a comb-like shape from these, and is formed by printing and drying a silver paste at the same time.

  The connection electrodes 3c and 3d have a substantially trapezoidal cross section.

  The main electrodes 3a and 3b and the connection electrodes 3c and 3d are printed by screen printing. That is, as shown in FIG. 3, the printing plate 4 has printing pattern openings 5a and 5b of the connection electrodes 3c and 3d. In FIG. 5, the resist edge portions 6a and 6b are inclined.

  Then, as shown in FIG. 4A, the silver paste 7 on the printing plate 4 is filled into the printing pattern openings 5 a and 5 b with the squeegee 8.

  Next, as shown in FIG. 4B, when the printing plate 4 is separated from the electrically insulating substrate 2, the silver paste 7 is transferred to the electrically insulating substrate 2 with the cross-sectional shape being substantially trapezoidal, By drying, the substantially trapezoidal connection electrodes 3c and 3d are formed.

  The polymer resistor 9 is formed by printing and drying so as to cover the connection electrodes 3c and 3d with polymer resistor ink.

  As the polymer resistor ink, a polymer resistor material in which carbon is kneaded in 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. doing.

  Next, the operation and action will be described.

  In FIG. 2, when the polymer resistor ink is printed so as to cover the connection electrodes 3c and 3d, the polymer resistor ink film is transferred along the substantially trapezoidal slope of the connection electrodes 3c and 3d. Since the film of the body 9 is not floating in the air and the boundary line between the substantially trapezoidal upper surface and the inclined surface is not a right angle, the film of the polymer resistor 9 is not cut.

  Therefore, no tear occurs in the film of the polymer resistor 9, and there is no problem such as no heat generation or partial heat generation, and uniform heat generation can be achieved.

  In this embodiment, the main electrodes 3a and 3b, the connection electrodes 3c and 3d, and the polymer resistor 9 are all formed by printing and drying. However, the electrode 3 is made of copper paste instead of silver paste. However, the method is not particularly limited to the printing / drying method.

As a method for forming each electrode, a copper foil may be cut according to an electrode pattern, and an edge portion having an inclined surface may be formed on the electrically insulating substrate 2 by pressing or the like.

(Embodiment 2)
FIG. 5 shows the second embodiment, which is different from the first embodiment in that the cross-sectional shape of one connection electrode 3e is formed in a triangular shape and the cross-sectional shape of the other connection electrode 3f is formed in an arc shape. .

  In addition, the place which performs the same effect | action as Embodiment 1 attaches | subjects the same code | symbol, and uses the thing of Embodiment 1 for concrete description.

  In the present embodiment, the main electrodes 3a and 3b and the connection electrodes 3e and 3f are printed by intaglio printing. As shown in FIG. 6, the printing plate 10 includes the print pattern cell 11a of the connection electrode 3e. The printed pattern cells 11b of the connection electrodes 3f are engraved in an arc shape in a triangular shape.

  As shown in FIG. 7A, the print pattern cells 11a and 11b are filled with the silver paste 7, and the printing plate 12 is brought into close contact with the electrically insulating substrate 2 and then separated as shown in FIG. 7B. Then, the silver paste 7 is transferred to the electrical insulating substrate 2 in a state where the cross-sectional shape is triangular and arc-shaped, and then dried, so that the connecting electrode 3e has a triangular cross-sectional shape and the connecting electrode 3f has an arc-shaped shape. It is formed.

  However, when the polymer resistor ink is printed so as to cover the connection electrodes 3e and 3f, the film of the polymer resistor 9 follows the triangular hypotenuse of the connection electrode 3e and the arc curve of the connection electrode 3f as shown in FIG. Since the film is transferred, the film of the polymer resistor 9 does not float in the air, and the top of the triangle of the cross-sectional shape of the connection electrode 3e is not a right angle, so the film is not cut.

  Therefore, no tear is generated in the film of the polymer resistor 9, and the polymer resistor 9 does not generate heat partially or abnormal heat is generated. Can do.

  As described above, the planar heating element according to the present invention is provided with the inclined surface at the edge portion of the connection electrode, so that no cracks are generated in the polymer resistor and a uniform heating state is obtained. However, the present invention is not limited to heating products such as floor heating panels and electric carpets, but can be applied to all heating elements in which resistors are formed and power supply electrodes are arranged.

2 Electrically Insulating Substrate 3 Electrode 3a, 3b Main Electrode 3c-3f Connection Electrode 4, 10 Printing Plate 5a, 5b Print Pattern Opening 6a, 6b Resist Edge 7 Silver Paste 9 Polymer Resistor 11a, 11b Print Pattern Cell

Claims (1)

An electrically insulating substrate, a pair of main electrodes formed on the substrate to face each other, a connection electrode extending from the main electrode in a comb-tooth shape, and formed so as to overlap the connection electrode; and A planar heating element comprising a polymer resistor formed by electrical coupling, wherein at least the connection electrode covered with the polymer resistor has a substantially triangular cross-sectional shape .

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