JPH0462448B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a chip-type film capacitor using a metallized dielectric film, and in particular, to a method for manufacturing a chip-type film capacitor using a metallized dielectric film, and in particular, using a polyphenylene sulfide film as the dielectric film; The present invention relates to a method for manufacturing a chip-type film capacitor that enables dip soldering by performing heat treatment before forming electrodes on the end face.

[Prior Art] Conventionally, chip-type film capacitors of this type have a structure in which metallized polyester films are wound in layers to form a capacitor element, and electrodes are provided on the end faces of the capacitor element. Depending on the requirements, external terminals are connected to the end electrodes and covered with epoxy or the like.

[Problems to be solved by the invention] However, in the above conventional chip-type film capacitor, the melting point of the polyester film is
Since the temperature is as low as 230°C and the shape of the capacitor is extremely small, reflow soldering is barely possible by limiting the heat conditions for soldering. Therefore, performing dip soldering on this chip-type film capacitor at a soldering temperature of approximately 260°C may cause large fluctuations in capacitance due to thermal deformation of the polyester film, poor connection of end electrodes, or a decrease in dielectric strength. This causes the reliability of the capacitor to be so low that it cannot be used, and is practically impossible to implement.

The present invention was devised in view of the above points, and
An object of the present invention is to realize a method for manufacturing a chip-type film capacitor, which can obtain a chip-type film capacitor that can be tape-soldered without reducing reliability by increasing heat resistance and preventing thermal deformation.

[Means for Solving the Problem] In order to achieve the above-mentioned object, the present invention forms a capacitor element by overlapping and winding metallized polyphenylene sulfide films, and the capacitor element is heated at 230°C to 270°C. The gist of the present invention is to provide a method for manufacturing a chip-type film capacitor, characterized in that electrodes are formed by thermally spraying an electrode material onto the end face of the capacitor element after heat treatment at a temperature of .

[Function] As described above, the present invention forms a capacitor element with a metallized dielectric film using polyphenylene sulfide, which has a melting point (285°C) higher than the soldering temperature (260°C) during dip soldering. death,
Since this is heat-treated at a temperature slightly lower than the melting point of polyphenylene sulfide and around the soldering temperature in dip soldering (230°C to 270°C), the chip mold manufactured by the present invention Even when dip soldering is applied to a film capacitor, thermal deformation of the dielectric film hardly occurs.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a perspective view showing a chip-type film capacitor manufactured according to the present invention connected to a lead frame. In the figure, 1 is a chip-type film capacitor, and 2 is a metalized polyphenylene sulfide 3 is a capacitor element, and 4 is an electrode.

To manufacture the chip-type film capacitor 1, first, a metalized polyphenylene film is formed by vapor-depositing aluminum onto the surfaces of a pair of dielectric films made of polyphenylene sulfide except for the margins at one end. Rufid film 2
The capacitor element 3 is formed by overlapping and winding so that the margin portions are arranged at different ends. Next, the capacitor element 3 is flattened by hot pressing and heat treated at a temperature of 230°C to 260°C for several minutes to several tens of minutes, and then electrode material is sprayed onto both end faces of the capacitor element to form the electrodes 4. The chip type film capacitor 1 is formed by forming the chip type film capacitor 1. The material constituting the electrode 4 is as follows:
Since an alloy containing tin, lead, zinc, antimony, etc. as main components and having a solidus temperature of 260° C. or higher is used, softening of the electrode 4 during dip soldering can be prevented.

After the chip-type film capacitor 1 formed by the above-described method is healed, external terminals 6 provided in the lead frame 5 are connected as necessary.
is welded to the electrode 4 on the end face, and then, as shown in FIG. 2, a molded sheathing 7 of thermosetting resin such as epoxy is applied, and then the frame portion 5a of the lead frame 5 is cut and removed, and the external terminal 6 is sheathed. If it is bent along line 7, weather resistance, handling properties, etc. will be further improved.

The external terminal 6 is made of a metal plate approximately 0.1 mm thick, and its end is bent upward at a substantially right angle to form a connecting piece 6a for connection to the chip-type film capacitor 1. Connection piece 6a
Both ends of the lower end are cut out to form a T-shape. Therefore, since the elasticity of the bent portion is weakened, the chip-type film capacitor 1
When welding the external terminal 6 to the chip-type film capacitor 1, even if there is some manufacturing error in the length of the capacitor 1, the bending angle of the bent portion will be an angle corresponding to the length of the capacitor 1.
The connection between the electrode 4 and the connecting piece 6a of the external terminal 6 is good. Furthermore, when a pair of welding electrodes is brought into contact with both ends of the upper part of the connection piece 6a and electricity is applied between both welding electrodes, the welding current is The flow concentrates in the upper part of the connecting piece 6a, thereby stabilizing the welding condition. Furthermore, the upper part of the connecting piece 6a bites into the electrode 4 due to the pressure of the welding electrode, so
Even if molding pressure is applied when applying the exterior 7, the electrode 4
Thermosetting resin does not flow into the space between the connecting piece 6a and the connecting piece 6a, and there is no possibility of an electrically disconnected state, so that a highly reliable connection is possible.

FIG. 3 shows external terminals connected to chip-type film capacitors formed by varying the heat treatment temperature in the manufacturing method shown in the above-mentioned embodiments.
This shows the characteristics when a material coated with epoxy resin is immersed in a solder bath at 260°C for 10 seconds. The chip-type capacitor mentioned above uses two 4-μm metalized polyphenylene sulfide films to have a capacitance of 0.01 μF. Figure 3A is the capacitance change rate with respect to processing temperature, Figure 3B
indicates the incidence of insulation defects with respect to processing temperature. As is clear from the figure, when the heat treatment temperature is 230℃ or higher, the absolute value of the capacitance change rate is small, within 1%, while when the heat treatment temperature is 270℃ or lower, no insulation failure occurs. .

[Effects of the Invention] As described above in detail, the present invention forms a capacitor element using a metallized polyphenylene sulfide film having a high melting point as a metallized dielectric film, and Since the electrodes are thermally sprayed after being heat-treated at a temperature slightly lower than the melting point of the dielectric film and around the soldering temperature in dip soldering, the dielectric film hardly undergoes thermal deformation even during dip soldering, and is As a result, a highly reliable chip-type film capacitor can be obtained in which fluctuations in capacitance are extremely small, the connection between the capacitor element and the end face electrode is strong, and the dielectric strength is high.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a state in which a chip-type film capacitor manufactured by the method of one embodiment of the present invention is connected to a lead frame, FIG. FIG. 3A is a graph showing the capacitance change rate versus heat treatment temperature, and FIG. 3B is a graph showing the insulation defect occurrence rate versus heat treatment temperature. 1... Chip type film capacitor, 2... Metallized polyphenylene sulfide film, 3...
Capacitor element, 4...electrode.

Claims (1)

[Claims] 1. A capacitor element is formed by overlapping and winding metallized polyphenylene sulfide films,
A method for producing a chip-type film capacitor, which comprises heat-treating the capacitor element at a temperature of 230° C. to 270° C. to cause it to shrink, and then thermally spraying an electrode material onto the end face of the capacitor element to form an electrode. 2. The method for manufacturing a chip-type film capacitor according to claim 1, wherein the solidus temperature of the sprayed electrode material is 260° C. or higher.