JP4637682B2 - Solid electrolytic capacitor - Google Patents

Description

  The present invention relates to a solid electrolytic capacitor, and more particularly, to a character and polarity display of a miniaturized solid electrolytic capacitor.

  In recent years, the demand for light, thin, and small solid electrolytic capacitors has progressed, and resin-molded tantalum solid electrolytic capacitors having an outer dimension of 1.6 mm × 0.8 mm have been put into practical use. FIG. 1 shows a perspective view of such a solid electrolytic capacitor, FIG. 2 shows a top view, and FIG. 3 shows a side view. As shown in FIGS. 1 and 3, an anode lead lead terminal 2a and a cathode lead lead terminal 2b are led out from the side surface of the exterior resin 1, and the lead terminals are lead-formed for surface mounting.

  All solid electrolytic capacitors need to display characters representing the product number and the like. When the outer dimensions of the exterior resin 1 are reduced as described above, naturally, the character display area 3 of the exterior resin 1 also becomes smaller, and it becomes difficult to display characters by the ink printing method. Therefore, the character display area 3 is mirror-finished, The periphery of the character display 4 was scraped off by a laser, and the characters were printed in a form that lifted up.

In addition to the characters, the solid electrolytic capacitor needs to be printed with a polarity display 5 representing the polarity of the lead terminal. Conventionally, in an ordinary solid electrolytic capacitor having a relatively large exterior resin size, this polarity is displayed by performing ink printing after performing ink printing, laser printing, or laser printing (for example, Patent Documents) 1).
Japanese Patent Laid-Open No. 7-50227

  In recent years, the miniaturization of solid electrolytic capacitors has progressed, and the thickness of the exterior resin has been reduced accordingly. The laser printing method has a problem that the reliability of the product is deteriorated because the thickness is further partially reduced. In addition, ink printing can print only the character display area 3 with a certain margin from the edge of the exterior resin, and thus there is a problem of wasting the narrow character display area 3.

In order to solve the above-mentioned problems, the present invention provides a solid electrolytic capacitor element in which an anode lead lead terminal and a cathode lead lead terminal are connected and led out, and then printed on the upper part of the resin-coated outer resin to indicate characters and polarity. In the solid electrolytic capacitor
A part of the exterior resin upper part is made into a mirror surface state, and it is a character display part by laser printing, and the anode lead terminal side of the exterior resin upper part is a pear-finished state to be a polarity display part by ink printing,
In the solid electrolytic capacitor, the character display portion is laser printing in which characters are dug with a laser.

According to the present invention, it is possible to accurately print a complicated part number mark and lot No. of a print content even in a narrow area by laser printing that digs characters into the character display area 3 finished in a mirror surface state, and You can maintain good visibility,
In addition, by printing ink on the polarity display section finished in a pear-finished state, the polarity display can be made clear and the interpretation of the polarity can be clarified, so that misreading of the polarity in the inspection process can be prevented. it can.
Furthermore, in the character printing area, there are few portions to be scraped off by laser processing, and the resin exterior portion of the polarity display portion is not thinned by laser processing, so that a solid electrolytic capacitor with good leakage current can be obtained.

[Example]
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a solid electrolytic capacitor according to this embodiment.
First, an oxide lead layer is formed as a dielectric on a sintered body that is molded into a predetermined shape and sintered in a state where an anode lead wire is embedded in tantalum powder that is a valve action metal. A manganese dioxide layer, a carbon layer, and a silver layer were sequentially formed to obtain a capacitor element. Next, the anode lead wire of the capacitor element and the anode lead terminal 2a are connected by resistance welding, and the capacitor element and the cathode lead terminal 2b are connected via a conductive adhesive. Thereafter, the exterior resin 1 is transferred using a molding die in which the surface of the character display area 3 after molding is made into a mirror surface and the surface of the polarity display portion is made into a pear-like state with a roughness of 5.0 to 8.0 μm. It was formed by a mold.

  Next, the character display area 3 in the mirror surface state is irradiated with laser to dig the surface to a depth of 8 to 10 μm, and the character display 4 is formed by laser printing. A cured ink was applied, cured by UV irradiation for 30 seconds, and a polarity display 5 was formed by ink printing. Thereafter, lead terminals were formed to produce a chip-type solid electrolytic capacitor having a length of 1.6 mm, a width of 0.8 mm, and a height of 0.8 mm.

[Comparative Example 1]
A solid electrolytic capacitor is produced in the same manner as in the example except that the exterior resin surface is a molding die that is in a pear-finished state, the exterior resin is transfer molded, and both character display and polarity display are performed by laser printing. did.

[Comparative Example 2]
A solid electrolytic capacitor was produced in the same manner as in the example except that the exterior resin was molded on the surface of the exterior resin using a mold that was in a pear-finished state, and the exterior resin was transfer molded and both the character display and polarity display were performed by ink printing. did.

[Comparative Example 3]
A solid electrolytic capacitor was produced in the same manner as in Example, except that the outer resin was transfer-molded with a molding die in a mirror state on the outer resin surface, and both character display and polarity display were performed by laser printing. .

[Comparative Example 4]
A solid electrolytic capacitor was produced in the same manner as in Example, except that the outer resin was transfer-molded with a molding die that was in a mirror state on the outer resin surface, and both character display and polarity display were performed by ink printing. .

  About the said Example and Comparative Examples 1-4, the marking misreading rate after printing was confirmed, and the moisture-proof load test (85 degreeC, 85%, 500 hours) after soldering (260 degreeC, 10 second reflow) was done. The leakage current failure rate was confirmed. The confirmed results are shown in Table 1.

Compared with Comparative Examples 1 to 4, the examples are improved in both the marking reading failure rate and the leakage current failure rate. This is because the polarity display portion is in a pear-skinned state, so that UV ink penetrates into the formed uneven portion, is not easily peeled off, a clear polarity display is made, and the character display area is in a mirror surface state. This is because it is glossy and can be clearly distinguished from polar display.
Furthermore, since there are few exterior resin parts scraped off with the laser of a character printing area, and it is not necessary to scrape off a polarity display part with a laser, the solid electrolytic capacitor with a favorable leakage current characteristic can be obtained.

It is a perspective view of a solid electrolytic capacitor. It is a top view of a solid electrolytic capacitor. It is a side view of a solid electrolytic capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior resin 2a Anode extraction lead terminal 2b Cathode extraction lead terminal 3 Character display area 4 Character display 5 Polarity display 6 Exterior resin upper part

Claims (1)

In the solid electrolytic capacitor in which the anode lead lead terminal and the cathode lead lead terminal are connected to the solid electrolytic capacitor element, and after the lead is connected, the printed resin showing the letter and polarity is applied to the upper part of the resin-coated outer resin.
A part of the exterior resin upper part is made into a mirror surface state, and it is a character display part by laser printing, and the anode lead terminal side of the exterior resin upper part is a pear-finished state to be a polarity display part by ink printing,
A solid electrolytic capacitor, wherein the character display portion is laser printing for digging characters with a laser.

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