JP2778157B2 - Manufacturing method of resistor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fixed resistor, a variable resistor, a sensor resistor or a heater resistor used in various electronic devices.

2. Description of the Related Art Resistors can be roughly classified into two types depending on the paint for electrodes and / or the paint for resistors to be used. That is,
Conductive powder / resin dispersion paint or conductive powder / glass frit dispersion paint. Conventionally, the former is around 200 ° C and the latter is 800
The resistor is manufactured by external heating and baking in a hot air drying oven or infrared oven at around ℃.

Problems to be Solved by the Invention The time required for firing is 10 in the case of conductive powder / resin dispersion paint.
Minutes to 30 minutes or more, and a baking time of 45 minutes to 60 minutes in the case of a conductive powder / glass frit dispersion paint, requires a large and long baking equipment in mass production.

The present invention has been made to solve such a conventional problem, and has as its object to enable extremely high-speed sintering in seconds, and to perform sintering with high-speed and compact equipment.

Means for Solving the Problems In order to achieve the above object, the present invention uses a metal substrate having an insulating layer on the surface as a substrate for a resistor, applies a paint for electrodes and / or a paint for resistance, and then applies a high-frequency induction. The heating heats the metal part of the resistor substrate, and the heat sinters each of the paints.

Function As described above, heating by high-frequency induction directly applies high energy to the metal of the resistor substrate, so it is possible to raise the temperature at an extremely high speed, and efficiently apply the coating film from the inside of the substrate through the insulating layer on the surface. Since it can be heated, it can be fired at a higher temperature than in the case of external heating, so that the curing time can be shortened in addition to the short heating time.

Example (Example 1) A phenol / xylene resin-based carbon paint was
Total thickness of insulating layer formed with μm epoxy resin insulating paint
Screen printing on a 0.48 mm aluminum metal plate (6 × 35 mm) in a predetermined pattern (2 × 22 mm) and heating at 200 ° C. for 15 minutes in an infrared / hot air oven as a comparative example, and an induction heater (400 KHz) as an example , 5KW: Seidensha Co., Ltd.)
Then, the surface temperature of the insulating layer was set to x ° C., and the temperature was raised at a rate of 60 ° C./second, and firing was performed for a total firing time of y seconds. Note that x is 250,280,320 and y is 10,20,30.
The induction heater is heated by the heating method that adjusts the induction power after the temperature is raised so that it can be kept at each set temperature.Furthermore, the electrode pattern is printed with epoxy resin and silver paint on both ends of the carbon paint pattern. Table 1 shows the measurement results of the rate of change in resistance after each resistor fired under the same conditions as above was left for 1000 hours each in a humidity atmosphere of a60 ° C. 90 to 95% RH and in a heat resistant atmosphere of b70 ° C. .

From the results shown in Table 1, it was confirmed that under the heat-curing condition of 250 to 280 ° C. for 10 to 20 seconds, the same or better performance as that of the conventional infrared / hot air heating furnace at 200 ° C. for 15 minutes was obtained.

(Example 2) Silver / palladium / glass frit paint (C-4610 manufactured by Sumitomo Metal Mining Co., Ltd.) on a metal core ceramic substrate (6 × 35 mm) (0.4 mm iron base, insulating layer 100 μm: manufactured by Fujikura Electric Cable)
A method of screen-printing the electrode pattern with a method of firing at 850 ° C. for a total time of 45 minutes in an infrared furnace as a comparative example,
As an example, an induction heater (400 KHz, 10 kW: manufactured by Seidensha Co., Ltd.) was used, the surface temperature was set to 850 ° C., the temperature was raised at a rate of 80 ° C./sec, and the total firing time was 50 hours. Bake in seconds, and further screen-print a ruthenium oxide-glass frit resistive paint (# 4740 manufactured by DuPont) connected to the electrode under the same conditions as above, and then perform resistance-temperature characteristics (TCR) of each baked resistor And A60 as reliable comparison
Table 2 shows the measurement results of the rate of change of resistance after each 1000 hours of standing in a humidity atmosphere of 90 to 95% RH and a heat resistance atmosphere of b70 ° C.
Shown in

As is clear from the above description, in the second embodiment, the resistor can be fired in a very short time. FIG. 1 is a schematic view of high-frequency induction heating in one embodiment of the present invention, wherein 1 is a high-frequency power supply, 2 is a copper metal tube formed by flowing cooling water, 3 is a metal plate such as aluminum, and 4 is An insulating layer 5 coated on the metal plate 3, an electrode paint 5 provided on the insulating layer 4, a resist paint 6,
Is an atmosphere temperature control heater using hot air or infrared rays for keeping the ambient atmosphere temperature constant.

Advantageous Effects of the Invention As is clear from the above embodiments, the present invention applies a coating for electrodes and / or a resistor to a metal substrate having an insulating layer on the surface, and directly applies each of the coatings from the inside of the substrate by high-frequency induction heating. By baking, a very short baking time is made possible. Furthermore, since the firing time is extremely short, when mass-producing as in the prior art, there is no need for a heavy and long firing facility, and the location and the facility can be made compact.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of high-frequency induction heating in one embodiment of the present invention. 1 ... high frequency power supply, 2 ... metal tube, 3 ... metal plate, 4 ...
... insulating layer, 5 ... paint for electrode, 6 ... paint for resistance, 7 ...
… Ambient temperature control heater.

Claims (2)

(57) [Claims] An electrode paint and / or a resist paint are applied on a metal substrate having an insulating layer on the surface, and the metal substrate is heated by high-frequency induction, and the electrode paint and / or the resist is coated via the insulating layer. A method for producing a resistor, comprising heating and baking a paint for resistance. 2. The method for producing a resistor according to claim 1, wherein the electrode paint and / or the resist paint is fired by simultaneously using high-frequency induction heating and hot air and / or infrared heating.