JPS61258402A - Semiconductor heat generating body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a semiconductor heating element having an automatic temperature control function.

"Conventional technology" Heating elements that utilize electrical resistance, especially planar heating elements, are used not only for home heating, but also for other purposes such as melting snow on roofs, preventing ice on roads, growing plants, keeping livestock, bridges, and runways warm. It has also come to be widely used in the field of writing.

Generally, sheet heating elements are often made of glass cloth mixed with carbon and synthetic resin, or those made by etching metal foil into a film.

"Problems to be Solved by the Invention J However, the conventional heating elements described above have drawbacks such as high cost, deterioration, and short lifespan, high defect rate in production, and unsatisfactory quality. This has been a major problem that has hindered its widespread use.

In order to solve the problems of the conventional heating element, the present invention has the following features:
Based on the idea of constructing a heating element by making use of inorganic gravel, sand, crushed stone, or resin berets, which can be obtained at extremely low cost, and making them conductive, we developed a system that is inexpensive, safe, and has zero
The present invention aims to provide a heating element that has a long life, is easy to manufacture and install, consumes little power, and is equipped with an automatic temperature control function.

[Means for Solving the Problems] As shown in the embodiment drawings @ Figures 1 to 6, the present invention provides conductive fine particles around non-conductive particles made of gravel, sand, synthetic resin particles, etc. The material is intimately kneaded with a synthetic resin and coated with a conductive film layer to form heat-generating particles with arbitrary electrical resistance.Most of these heat-generating particles are kneaded with a heat-resistant synthetic resin to form the desired plate shape. Alternatively, it is characterized in that it is formed into a rod-like object, and different types of electrodes are provided at intervals therein to form an electrical resistor, and the outer periphery of this electrical resistor is electrically insulated.

"Operation" When electricity is passed between both electrodes, heat is generated due to the electrical resistance in the conductive coating layer of the heat generating particles. When the temperature rises, the synthetic resin portion of the conductive coating layer expands, thereby changing the density of the mixed conductive fine particles and gradually becoming sparse. As a result, the resistance value increases and the current decreases accordingly. That is, the heating element of the present invention has a positive characteristic (PTC effect), and has the property that when the temperature rises, the current decreases, and when the temperature falls, the current returns to the initial energization state. The temperature of the heating element is automatically controlled.

Furthermore, among the PTC effects, there are ceramic heaters that have positive characteristics, but the PTC effect is extreme, and a large current flows instantly when the current is applied, and the current decreases rapidly when the selected m current is reached. . Therefore, it is difficult to manufacture a device with a large area, and a large current flows at the instant of energization. On the other hand, the PTC effect of the heating element of the present invention is such that a large current does not flow even at the moment of energization, and the current gradually decreases as the temperature rises. fll
There is k.

"Embodiments" Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway side view showing one embodiment of the heating element of the present invention. In the figure, reference numeral 1 denotes an electrical resistor that constitutes the bulk of the heating element, and is formed into a rod shape with a circular cross section.A pair of different electrodes 2°3 are provided at intervals within the resistor, and their ends protrude outward. has been done. An electrical insulating layer 4 made of synthetic resin or the like is applied to the outer periphery of the electrical resistor l.

As shown in FIG. 2, the electric resistor l has many heat generating particles 5
is kneaded with a heat-resistant synthetic resin 8, and the heat-generating particles 5 are made of expanded particles such as carbon around non-conductive particles 6 such as inorganic particles such as gravel or sand, or synthetic resin pellets. It has a structure in which a conductive exposed layer 7 made of conductive fine particles 9 having a small coefficient and a synthetic resin 10 intimately kneaded (FIG. 3) is adhered thereto. The conductive film layer 7 can be attached to the non-conductive particles 6 by using a synthetic resin 1O having good adhesive properties, or by baking and drying.

The heating element of the present invention has conductivity of 1! A conductive particulate material 9 such as carbon is used as the material of the coating layer 7 that provides properties.
The expansion is negligible, but since a synthetic resin with a large expansion coefficient is used as the other material of the coating layer 7, if there is an overcurrent between the electrodes 2 and 3, the temperature will rise due to the resistance of the coating layer 7. As the temperature rises, the synthetic resin IO will begin to expand. Then, as the synthetic resin expands, the conductive fine particle material 9 in the coating layer 7 will move as shown in FIG.
As a result, the density of the wires gradually becomes sparse, the resistance value increases, and the current flow decreases.

For this reason, when manufacturing the heating element of the present invention, it is sufficient to set a resistance value suitable for obtaining the required degree m. Further, in order to obtain the necessary temperature characteristics, it is sufficient to select the magnitude of the expansion coefficient of the synthetic resin agent to be kneaded and set its saturation temperature.

Thereby, the required temperature will be controlled automatically. For example, if the upper limit saturation temperature is to be 80°C, a synthetic resin that starts expanding at around 80°C may be used as the material.

When an inorganic material with a large specific heat, such as gravel or sand, is used as the non-conductive particles 6 of the heat generating particles 5, it is difficult to cool down once the particles are heated to -, so power consumption can be greatly reduced. Also, non-conductive
If a material with high retardancy such as synthetic resin pellets is used for the magnetic particles 6, the non-conducting MF+ particles 6 themselves expand as the temperature rises, so the PTC effect increases, making current control and temperature control more sensitive. It can be done.

5 and 6 show other embodiments of the heating element of the present invention, in which the electric resistor l is formed into a rectangular bar shape. In this case, and in the case of FIG. 5, the electrode 2.3 protrudes from both ends, but it may also protrude from only one end. Also.

FIG. 6 shows an example in which the gas resistor l is formed into a flat plate shape.

In this case, the electrodes 2.3 are protruding from the opposite sides, but the north pole 2.3 can of course be made as shown in the examples in Figures 1 and 5. Of course, the electrodes 2.3 in the examples of FIGS. 1 and 5 can also be made as in the example of FIG. 6.

"Effects of the Invention" As explained above, in the present invention, a conductive membrane layer made of conductive fine particles such as carbon and a synthetic resin is coated around non-conductive particles such as gravel. Most of the heat-generating particles were kneaded with synthetic resin and molded into electrical resistors, so P
A heating element having a TC effect can be obtained, and by selecting conductive fine particles and synthetic resin, one having a desired temperature % property and high electrical stability can be easily produced by a simple manufacturing method. In addition, the cost is low because the materials are cheap, and since gravel, sand, carbon, etc. are used, there is extremely little deterioration, so it can be used stably for a long period of time, and the shape of the heating element can be changed as desired. It has many excellent effects, including an extremely wide range of applications.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view showing an embodiment of the heating element of the present invention;
Fig. 2 is a partially enlarged cross-sectional view of the electric resistor, Fig. 3 is a partially enlarged cross-sectional view of the conductive film layer, Fig. 4 is a cross-sectional view showing the state at the time of expansion, and Fig. 5 is another embodiment. FIG. 6 is a perspective view showing an example. FIG. 6 is a perspective view showing still another embodiment.

Claims (1)

[Claims] A conductive coating layer made by kneading conductive fine particles with synthetic resin is applied around non-conductive particles to form heat-generating particles with arbitrary electrical resistance. is kneaded with synthetic resin and formed into the required plate or rod shape, and electrodes of different types are placed at intervals within the material to form an electrical resistor, and the outer periphery of this electrical resistor is electrically insulated. A semiconductor heating element characterized by: