JPS63197318A - metallized film capacitor - 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 The present invention relates to a metallized film capacitor with high capacitance accuracy.

When metallized film capacitors are manufactured using normal manufacturing methods, the variation in capacitance is about ±10%.

In order to further reduce variations in capacitance, it is necessary to add a special process to the capacitor manufacturing process.

Therefore, the quality and price of metallized film capacitors with high capacitance accuracy depend on the additional steps required.

Capacitors with high capacitance accuracy are used in a wide range of applications such as oscillation circuits, and it is desirable to be able to manufacture high-quality capacitors using a mass production method.

The present invention was made to solve these problems, and it has become possible to manufacture a high-precision capacitor with a capacitance accuracy of ±1%.

Next, a method for increasing capacitance accuracy will be explained.

At the stage when a product is completed using normal production methods, there are restrictions on the measures that can be taken, and the only way to increase accuracy is by selecting the capacitance or by combining two capacitors.

In either method, a large number of capacitors that fail capacitance screening will be discarded as defective products, and the cost will be directly converted into the cost of non-defective products.

Therefore, a significant increase in product prices is inevitable.

Furthermore, this is not a very desirable method from the viewpoint of effective use of materials.

Adjustment of the capacitance can also be carried out at the initial stage of capacitor manufacture, ie, during the process of superimposing and winding two layers of metallized film.

In this method, capacitance is measured during winding of the capacitor element, and winding is terminated when the desired capacitance is reached.

Further, when a desired capacity is reached during winding, the metallized film is removed by burn-off, and thereafter only the film is wound, regardless of the capacity.

However, even in a capacitor element whose capacitance is controlled to a specified value during winding, the capacitance changes due to heat and pressure in the manufacturing process after winding, and variations in capacitance occur in the final manufacturing process.

Therefore, the capacitance accuracy according to this method is limited to approximately ±5%, and in order to achieve a higher accuracy, that is, approximately ±1%, it is necessary to consider another method.

In the manufacturing process of metallized film capacitors, the present invention focuses on metallization, heat treatment, and
After impregnation, etc., the capacitor element immediately before the exterior packaging, which is closest to the final process, is processed to obtain the specified capacity.

This method is carried out by manufacturing a capacitor element with a capacity slightly larger than the specified capacity to be obtained, and cutting a notch into the capacitor element.

In the case of a capacitor wrapped with aluminum foil and film, such a notch causes a short circuit and cannot be used, but in the case of a metallized film capacitor, the unique self-healing effect prevents a short circuit and maintains its capacity. be able to.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an element of a wound metallized film capacitor, in which (a) shows a conventional element and (b) shows an embodiment of the present invention with a notch. In the case of wound-type metallized film capacitors, wind up an element that exceeds the desired capacity by a few percent (conventional type (Fig. 1 A)), make a cut in it, adjust the capacitance, and achieve the specified value. The element is completed in the shape of the capped state (opening in Figure 1).

FIG. 2 shows an element of a laminated metallized film capacitor, in which (a) is a conventional element and (b) is an embodiment in which a notch or cutout according to the present invention is provided.

In the case of a laminated metallized film capacitor, the element (conventional type, Figure 2 A) is manufactured to have a capacitance approximately 0.5% higher than the desired capacity, and a notch or notch is made in the element to increase the capacitance. After adjustment, the device is completed in the shape of the specified capacitance (as shown in Figure 2).

There are many methods used to process these cuts and notches, such as using a cutter and using a laser. In either case, the number of man-hours is small, the work is simple, and processing can be performed with high precision.

[Brief explanation of the drawing]

Figure 1 (a) shows the conventional element structure of a wound type metallized film capacitor. Figure 1 (b) shows the element structure of the present invention of a wound type metallized film capacitor. Conventional element structure of a film capacitor Figure 2 (b) shows the element structure of the present invention of a laminated metallized film capacitor.

Claims (1)

[Claims] In a wound or laminated metallized film capacitor, the capacitor element is treated with metallicon to take out the electrodes, and then the capacitance is adjusted by notching or notching to obtain the specified capacitance. metallized film capacitor.