JP2002015846A - Sheet-like heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like heating element 1, capable of enhancing temperature rise performance, suppressing deterioration in heating distribution, enlarging the freedom of design, and keeping heating action, even if a pair of electrodes is broken. SOLUTION: This sheet-like heating element has a pair of first electrodes 3a, 3b placed on an insulating substrate 2 and formed by printing of conductive paste containing conductive powder and drying; a PTC-heating element 4 placed on the first electrodes 3a, 3b; and a pair of second electrodes 5a, 5b placed on the PTC heating element 4 and formed by printing of the conductive paste containing conductive powder and drying, and the first electrodes 3a, 3b and the second electrodes 5a, 5b are formed in the same pattern, piled up on each other, and connected electrically in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet heating element. The sheet heating element of the present invention is used, for example, as a door mirror heater for vehicles such as automobiles.

[0002]

2. Description of the Related Art Conventionally, a planar heating element 51 shown in FIGS. 5 and 6 has been known, and is configured as follows.

[0003] First, an insulating film 52 as an insulating substrate is provided, and a conductive powder such as silver is contained on the insulating film 52 (on the lower side in FIG. 6). A pair of electrodes 53a and 53b formed by printing and drying the conductive paste (ink) thus formed are provided. A PTC heating element 54 printed and dried on the electrodes 53a, 53b is provided on the electrodes 53a, 53b, and an insulating film 55 as an insulating cover is provided on the heating element 54. Is covered. A pair of electrodes 53
Terminals 56a and 56b are connected to a and 53b, respectively.

However, in the planar heating element 51 shown in FIGS. 5 and 6, only a pair of electrodes 53a and 53b for supplying a current to the heating element 54 are provided on one side of the heating element 54. There are the following disadvantages.

At the time of energization, the electrodes 53 a and 53 b (especially near the terminals) generate heat before the heating element 54, so that the temperature raising performance may not be very good. When the plane area of the entire planar heating element 51 is almost constant, the width of the electrodes 53a and 53b needs to be widened when a large current flows, so that the heating area of the heating element 54 is reduced accordingly. Therefore, the heat generation distribution may be deteriorated. This inconvenience is manifested as a reduced degree of freedom in design. Also, as a solution, the electrodes 53a, 5
There is a method of increasing the coating thickness of 3b, but this has a limit. Since the pair of electrodes 53a and 53b is the only one, when the electrodes 53a and 53b are cut off, no current flows from there and no heat is generated.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention improves the heating performance of a heating element, suppresses the deterioration of heat generation distribution, increases the degree of freedom in design, and cuts a pair of electrodes. It is an object of the present invention to provide a sheet heating element capable of maintaining a heating action even when the heating is performed.

[0007]

In order to achieve the above object, a planar heating element according to claim 1 of the present invention is formed by printing and drying a conductive paste containing a conductive powder which is superimposed on an insulating substrate and contains a conductive powder. A pair of formed first electrodes, a PTC heating element overlaid on the first electrode, and a pair of PTC heating elements overlaid on the PTC heating element and formed by printing and drying a conductive paste containing conductive powder. A second electrode, wherein the first electrode and the second electrode are formed in the same pattern, overlap each other, and are electrically connected in parallel.

A planar heating element according to a second aspect of the present invention has a pair of first electrodes provided on one side of a heating element and a second electrode provided on the opposite side. The electrode and the second electrode are formed in the same pattern, overlap each other, and are electrically connected in parallel.

In the planar heating element according to the first aspect of the present invention having the above-described structure, a pair of first electrodes made of a conductive paste containing conductive powder are provided on one side of the PTC heating element and on the other side. Is provided with a pair of second electrodes made of a conductive paste also containing conductive powder, because the first electrode and the second electrode are formed in the same pattern with each other and are stacked with the PTC heating element interposed therebetween. By passing a current through both electrodes, it becomes possible to pass a larger current than in the case of the one-sided electrode in the above-mentioned conventional technology. In addition, when the electrode heat generation temperature is considered to be the same, the width of the electrode may be half as compared with the case of the one-sided electrode in the above-mentioned conventional technology, so that the heat generation area can be increased accordingly. Further, since both electrodes are electrically connected in parallel, even if one of the electrodes is cut off, it is possible to allow a current to flow through the other electrode.

Further, the present invention has the above-mentioned structure.
In the planar heating element, a pair of first electrodes is provided on one side of the heating element and a pair of second electrodes is provided on the opposite side, and the first electrode and the second electrode are formed in the same pattern as each other. Since the heating elements are stacked with the heating element interposed therebetween, it is possible to flow a larger current than in the case of the one-sided electrode in the above-described conventional technique by flowing a current to both electrodes. In addition, when the electrode heat generation temperature is considered to be the same, the width of the electrode may be half as compared with the case of the one-sided electrode in the above-mentioned conventional technology, so that the heat generation area can be increased accordingly. Further, since both electrodes are electrically connected in parallel, even if one of the electrodes is cut off, it is possible to allow a current to flow through the other electrode. This claim 2
The kinds of electrodes in the sheet heating element according to the present invention include those made of a conductive paste containing a conductive powder as described in claim 1, and those made of a metal foil such as a copper foil.

Further, the present invention includes the following technical ideas.

The planar heating element proposed in the present application is a PTC heating element after an electrode A is formed by printing and drying a conductive paste (ink) containing a conductive powder such as silver on an insulating film. (Ink) is printed and dried, and the electrode B (a conductive paste (ink) containing a conductive powder such as silver again) is printed and dried. It has the following features. (1) The electrode A and the electrode B have the same pattern (the electrodes of the a-pole and the b-pole exactly overlap each other due to left and right differences). (2) The a-pole of the electrode A and the a-pole of the electrode B, and the b-pole of the electrode A and the b-pole of the electrode B are joined at their terminals (the electrodes A and B are connected in parallel). .

The sheet heating element proposed by the present application is:
After printing and drying electrode A on the insulating film, PTC
The heating element (ink) is printed and dried, and the electrode B is printed and dried again to form a PTC heating element. That is, the electrodes A and B are formed on both sides of the heating element, respectively. The electrode A and the electrode B are paste-like inks containing conductive particles such as silver, and have a configuration in which electrodes of the same pattern (the electrodes of the a-pole and the b-pole are exactly overlapped with each other) have different shapes. Has become. Electrode A and electrode B
Are joined at the terminal section (there is no joining at the terminal section because there is no heating element). In addition, the terminal is covered with caulking and an insulating film (with an adhesive) to produce a product.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a plan view of a planar heating element 1 according to an embodiment of the present invention, and its cross section is shown in FIG.

The illustrated planar heating element 1 is configured as follows.

First, an insulating film 2 as an insulating substrate is provided, and a conductive powder such as silver is contained on the insulating film 2 (the lower side in FIG. 2). And a pair of first electrodes 3a, 3b formed by printing and drying the conductive paste (ink) formed as described above.
On the first electrode 3a, a PTC heating element 4 printed and dried on the first electrodes 3a, 3b is provided.

A pair of conductive paste (ink) containing a conductive powder such as silver is printed and dried on the PTC heating element 4 on the heating element 4. Second electrodes 5a and 5b are provided, and an insulating film 6 as an insulating cover is put on the second electrodes 5a and 5b.

The first electrodes 3a, 3b and the second electrodes 5a,
5b are formed of the same kind of material in the same pattern on a plane and have the same or substantially the same thickness. The first electrodes 3a, 3b and the second electrodes 5a, 5b
The terminals 7a and 7b are connected to each other in such a manner that the terminal connection portions corresponding to each other are overlapped with each other.

The planar heating element 1 having the above configuration is installed on the back side of a door mirror as a door mirror heater for a vehicle such as an automobile, and is characterized in that the above configuration has the following operational effects. are doing.

First, a pair of first electrodes 3a and 3b made of a conductive paste containing a conductive powder is provided on one surface of the PTC heating element 4 and a conductive material containing the same conductive powder is provided on the other surface. A pair of second electrodes 5a and 5b made of paste are provided.
b and the second electrodes 5a, 5b are formed in the same pattern with each other and are vertically stacked with the heating element 4 interposed therebetween. Therefore, by flowing a current to both electrodes 3a, 3b, 5a, 5b, It is possible to pass a larger current than in the case of a single-sided electrode (2 times larger than a single-sided electrode).
As a result, as shown in the graph of FIG. 5, when the current value is the same, the heat generation temperature of the electrodes 3a, 3b, 5a, 5b can be reduced (1/3 compared to the one-sided electrode).
2). Therefore, during energization, the electrodes 3
a, 3b, 5a, 5b can be suppressed from generating heat, and the temperature raising performance can be improved.

As shown in the graph of FIG. 6, when the electrode heat generation temperature is the same, the width of each of the electrodes 3a, 3b, 5a, 5b is half that of the one-sided electrode in the prior art. The heating element 4
Can increase the heat generation area, thereby improving the heat generation distribution. In addition, the degree of freedom of design of the sheet heating element 1 can be increased.

Further, since the first electrodes 3a, 3b and the second electrodes 5a, 5b are electrically connected in parallel, even if one of the electrodes is cut, a current can flow through the other electrode. Thus, even if any of the electrodes are cut off, the heating element as a whole can maintain the heating action. Therefore, the reliability of the product can be improved.

[0024]

The present invention has the following effects.

That is, first, in the planar heating element according to the first aspect of the present invention having the above structure, a pair of first electrodes made of a conductive paste containing conductive powder are provided on one side of the PTC heating element. A pair of second electrodes made of a conductive paste also containing conductive powder are provided on the opposite side, and the first electrode and the second electrode are formed in the same pattern and are stacked with the PTC heating element interposed therebetween. Therefore, it is possible to flow a larger current than in the case of the one-sided electrode in the related art by flowing a current to both electrodes, thereby reducing the heat generation temperature of the electrode when the current value is the same. Therefore, it is possible to suppress the electrode from generating heat prior to the heating element during energization, and to improve the temperature raising performance. If a large current can be passed, a high-performance heater having a low resistance value can be manufactured.

Further, assuming that the electrode heating temperature is the same, the width of the electrode may be about half as compared with the case of the one-sided electrode in the prior art, so that the heating area of the heating element can be increased accordingly. , Whereby the heat generation distribution can be improved. In addition, it is possible to expand the degree of freedom in designing the planar heating element.

Further, if the heat generation temperature of the electrode can be set low even if the electrode width is small, the following effects can be obtained. That is, first, when the electrode generates heat, the heat generation distribution differs from the designed one. According to the present invention, this can be prevented, and second, the life of the electrode can be extended.
Third, when the temperature of the electrode is increased, the resistance value is further increased. According to the present invention, this can be prevented.

Further, since the first electrode and the second electrode are electrically connected in parallel, even if one of the electrodes is cut,
It is possible to pass current at the other electrode,
As a result, even if one of the electrodes is cut off, the heating element as a whole can maintain the heating action. Therefore, the reliability of the product can be improved.

Further, the present invention having the above-mentioned structure is characterized by claim 2
In the planar heating element, a pair of first electrodes are provided on one side of the heating element and a pair of second electrodes are provided on the opposite side, and the first electrode and the second electrode are formed in the same pattern to generate heat. Since the electrodes are stacked with the element interposed therebetween, it is possible to flow a larger current than in the case of the one-sided electrode in the related art by flowing a current to both electrodes, thereby generating heat of the electrode when the current value is the same. The temperature can be reduced. Therefore, it is possible to suppress the electrode from generating heat prior to the heating element during energization, and to improve the temperature raising performance. If a large current can be passed, a high-performance heater having a low resistance value can be manufactured.

Further, assuming that the electrode heating temperature is the same, the width of the electrode may be about half as compared with the case of the one-sided electrode in the prior art, so that the heating area of the heating element can be increased accordingly. , Whereby the heat generation distribution can be improved. In addition, it is possible to expand the degree of freedom in designing the planar heating element.

If the heat generation temperature of the electrode can be set low even if the electrode width is small, the following effects can be obtained. That is, first, when the electrode generates heat, the heat generation distribution differs from the designed one. According to the present invention, this can be prevented, and second, the life of the electrode can be extended.
Third, when the temperature of the electrode is increased, the resistance value is further increased. According to the present invention, this can be prevented.

Also, since the first electrode and the second electrode are electrically connected in parallel, even if one of the electrodes is cut,
It is possible to pass current at the other electrode,
As a result, even if one of the electrodes is cut off, the heating element as a whole can maintain the heating action. Therefore, the reliability of the product can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a sheet heating element according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the planar heating element.

FIG. 3 is a graph showing a relationship between a current value flowing through an electrode and a heating temperature of the electrode.

FIG. 4 is a graph showing the relationship between electrode width and electrode heating temperature.

FIG. 5 is a plan view of a sheet heating element according to a conventional example.

FIG. 6 is a cross-sectional view of the planar heating element.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sheet heating element 2 insulating film (insulating substrate) 3a, 3b first electrode 4 PTC heating element (heating element) 5a, 5b second electrode 6 insulating film (insulating cover) 7a, 7b terminal

Claims (2)

[Claims] 1. A pair of first electrodes (3a) and (3b) formed by printing and drying a conductive paste containing a conductive powder and superposed on an insulating substrate (2);
A PTC heating element (4) superimposed on the first electrodes (3a) and (3b), and a conductive paste containing a conductive powder and superposed on the PTC heating element (4) were formed by printing and drying. A pair of second electrodes (5a) (5
b) and the first electrode (3a) (3b) and the second electrode (5a)
(5b) A planar heating element formed in the same pattern, overlapping each other, and electrically connected in parallel. 2. A semiconductor device comprising: a pair of first electrodes (3a) and (3b) provided on one side of a heating element (4); and second electrodes (5a) and (5b) provided on opposite sides. First electrode (3a) (3b) and second electrode (5a)
(5b) A planar heating element formed in the same pattern, overlapping each other, and electrically connected in parallel.