JPS6244477Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is intended to improve the reliability of the connection between the main electrode of a planar heating element and the heating resistor film.

A conventional planar heating element has a strip-shaped main electrode 2 on the surface of an insulating substrate 1, as shown in FIGS. 1 and 2.
2' are arranged in parallel and facing each other, and a heating resistor film 4 is provided between the opposing main electrodes 2, 2', including the inner edge portions of the main electrodes 2, 2' facing each other. The structure was such that other conductive films, ie, auxiliary electrode films 3 and 3', were successively provided nearby. Figures 3 and 4 are also conventional example 1.
It consists of three main electrodes 2, 2', 2'' facing each other, and a heating resistor film 4 is provided between each of these main electrodes 2, 2', 2'', and another auxiliary electrode is provided at the edge. The coatings 3, 3', 3'', and 3 were constructed in sequence.

Here, the purpose of providing the auxiliary electrode film 3 made of another conductive paint will be described. Generally, when the heating resistor film 4 is constructed by applying carbon paint and drying it, a film made of metal foil or conductive paint is used as the main electrode 2, but the heating resistor film 4 The heating resistor film 4 is extremely thin and thermal expansion/shrinkage occurs during drying.
There is a risk that the wire will break at the edge of the main electrode 2 (broken wire phenomenon). For this reason, another conductive film 3 was formed near the edge of the main electrode 2 to reinforce the edge and improve the connection between the main electrode 2 and the heating resistor film 4. In other words, it was a film that had the function of an auxiliary electrode.

By the way, as is clear from the cross-sectional structures in FIGS. 2 and 4, in the conventional example, another conductive film 3 is applied from above the heating resistor film 4, and is not in contact with the surface of the main electrode 2. It was configured in a non-contact manner. When applying (printing) the heating resistor film 4, in order to apply it from end to end of the main electrode 2, that is, to completely cover the entire surface of the main electrode 2, another conductive film, that is, an auxiliary electrode, is required. The film 3 was structured so that it did not come into direct contact with the surface of the main electrode 2.
In this conventional example, if the heating resistor film 4 breaks at the edge of the main electrode 2 as shown in FIG.
Although the electrical connection was supplemented by the auxiliary electrode film 3, the current path flows from the main electrode 2 to the heat generating resistor film 4' provided on the main electrode 2, and then to the auxiliary electrode film 3 on the upper layer. , and then flowed to the original heating resistor film 4. The problem here is the conductivity of the heating resistor film 4' provided on the main electrode. In the current path 2-4'-3-4 in FIG. 5, the resistance value in the heat generating resistor film layer 4' cannot be ignored, and it is an obstacle to supplying a normal current to the heat generating section.

The present invention is intended to eliminate such drawbacks, and one embodiment of the present invention will be described below with reference to FIGS. 5 to 8.

Three strip-shaped main electrodes 6, 6', 6'' are provided on the surface of the insulating substrate 5 to form two pairs of opposing electrodes. The heating resistor film 7 is applied and dried to form exposed parts A, B, and C at the center of the upper surface of the main electrodes 6, 6', and 6''.Then, the exposed parts A, Apply another conductive paint to the main electrodes 6, 6', 6'' including B and C and the heating resistor coating parts A, B, C, and D near the edges of these main electrodes 6, 6', 6''. The auxiliary electrode films 8, 8', 8'' are formed to constitute a planar heating element.

As shown in FIG. 9, the planar heating element of the present invention having the above structure allows the main electrode 6 and the auxiliary electrode film 8 to come into direct contact even if the heating resistor film 7 is cut off at the edge of the electrode 6. Therefore, the current flows as 6-8-7, and a normal current can be supplied to the heating resistor film 7. Therefore, the reliability of the connection between the main electrode and the heat-generating resistor film is increased, and this has a great practical effect.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a conventional planar heating element, Fig. 2 is a sectional view thereof, Fig. 3 is a plan view of another conventional planar heating element, Fig. 4 is a sectional view thereof, and Fig. 5 is a sectional view of the same. FIG. 6 is a cross-sectional view of a conventional planar heating element with the heating resistance film cut away; FIG. 6 is a plan view of a planar heating element according to an embodiment of the present invention;
FIG. 7 is a cross-sectional view of the same, FIG. 8 is a cross-sectional view of the state before the heat-generating resistive film is attached, and FIG. 9 is a cross-sectional view of the state where the heat-generating resistive film is cut. 5...Insulating substrate, 6...Main electrode, 7...Heating resistor film, 8...Auxiliary electrode film.

Claims (1)

[Scope of utility model registration request] A surface shape in which opposing main electrodes are provided on an insulating substrate, a heating resistor film is formed between the opposing main electrodes, and an auxiliary electrode film is formed on the edge portion of the main electrode and its vicinity. In the heating element,
A planar heating element characterized in that a heating resistor coating is formed so that at least a portion of the main electrode is exposed, and an auxiliary electrode coating is brought into contact with the exposed portion of the main electrode.