JPH0328501Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a chip type capacitor, and in particular, by forming a heat reflective layer on the exterior member of the chip type capacitor,
This article relates to chip-type capacitors with improved heat resistance during soldering, etc.

In recent years, with the miniaturization of electronic devices, the electronic components used therein have also been miniaturized and chipped, and capacitors are no exception.

In general, a chip type capacitor 1 using a capacitor element such as a tantalum capacitor, an aluminum electrolytic capacitor, or a film capacitor has a capacitor element 2 connected to a pair of external terminals 3 made of minute metal pieces, as shown in FIGS. 1 and 2. Connect 3',
It has a structure in which it is covered with a synthetic resin exterior member 4 by molding, and symbols 6 such as ratings are stamped and displayed on the exterior member 4 as necessary.

However, when incorporating the chip capacitor into an electronic device, when soldering is performed by a reflow method in which the chip capacitor is placed on a wiring board and passed through a high-temperature atmosphere, the thickness of the exterior member that covers the capacitor element is thin. Therefore, a large amount of heat is applied to the capacitor element. For example, when the capacitor element is a plastic film capacitor element, the plastic film shrinks and deforms due to the above-mentioned thermal effects, causing a change in capacitance, and in extreme cases, the plastic film is damaged and the insulation deteriorates. and short circuits, which significantly deteriorate the electrical characteristics and reliability of such chip capacitors.

Conventionally, as a countermeasure to this problem, materials with low thermal conductivity or high heat reflectivity have been selected for exterior members, but exterior members should originally have good electrical and environmental properties. The reality is that it is not always possible to achieve a sufficient heat resistance effect due to the demands and balance with these various properties.

This invention was devised to solve the above problems, and even when heat is applied during soldering etc., the internal capacitor element is not affected by the heat, and the electrical characteristics The purpose is to provide a chip type capacitor with good performance and high reliability.

The above purpose is to provide a chip-type capacitor in which the capacitor element is covered with an exterior member and external terminals are led out, which is the gist of the present invention. This is achieved by a chip-type capacitor characterized by forming a heat-reflecting layer made of paint.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

3 to 5 show a chip type capacitor (in this case, an example using a plastic film capacitor element) according to an embodiment of the present invention, and in the figures, the chip type capacitor 1 is ,
For example, the capacitor element 2 is made by laminating and winding a metallized polyester film, flattening it by heat pressing, and applying metallization to both end surfaces.
It has a structure in which a pair of external terminals 3 and 3' formed by punching out a metal plate of approximately 0.1 mm are connected, and this is covered with an exterior member 4 made of a synthetic resin material such as epoxy using a mold. . Further, the portions of the external terminals 3, 3' that are led out of the exterior member 4 are arranged on the end surface and the lower surface of the exterior member 4. Furthermore, a heat reflective layer 5 is formed on the surface of the exterior member 4 where the external terminals 3, 3' are not present, that is, on the top surface and side surfaces.

The materials constituting the heat reflective layer 5 are as follows:
A heat-resistant ceramic paint consisting mainly of a mixture of metal oxides such as SiO ₂ , TiO ₂ , MgO and stainless steel powder and a binder added thereto is suitable. After being diluted and deposited on the exterior member 4 of the chip-type capacitor 1 by spraying or coating, the heat-reflecting layer 5 is formed by leaving it at room temperature or drying it by heating. An arbitrary symbol 6 such as a rating, a mark, a management symbol, or other symbol is written on the upper surface of the heat reflective layer 5.

However, when the chip capacitor 1 is irradiated with heat, most of the radiant heat from the heat source is reflected by the heat reflective layer 5, and the heat conduction to the capacitor element 2 is small.

In order to measure the effectiveness of this invention, we used a 1.5 μm thick and wide
Capacitance is achieved by laminating and winding a 4.5mm polyester film and a metallized film with aluminum vapor deposited on it.
A 0.1 μF capacitor element is formed and the average thickness is
A heat resistance test (conditions: 230℃,
When tested for 10 seconds), the capacitance change rate was about 1/10th of that with the heat reflective layer compared to the one without, and the insulation resistance also showed a high value.

In this embodiment, protruding pieces 7, 7' having a substantially U-shaped cross section are formed integrally with the external terminals 3, 3' and are arranged around the capacitor element 2, thereby also providing heat shielding. It is something that produces an effect. In addition, although this embodiment shows an example using a plastic film capacitor element, the present invention is not limited to this, and the same applies to chip type capacitors using other capacitor elements such as electrolytic capacitor elements. It can be applied to

As detailed above, the chip-type capacitor of the present invention has a heat-reflecting layer made of a heat-reflecting paint containing metal oxide and stainless steel powder as its main components on its exterior member, so that the applied heat is Since only a very small amount of heat is reflected by the heat-reflecting layer and conducted to the capacitor element, there is no risk of capacitance reduction or insulation deterioration in the capacitor element, resulting in good electrical characteristics. and is highly reliable.

[Brief explanation of drawings]

Figures 1 and 2 show a conventional chip capacitor, with Figure 1 being a perspective view of the product in progress, Figure 2 being a perspective view of the finished product, and Figures 3 to 5 showing the structure of the present invention. Fig. 3 is a perspective view of the finished product, Fig. 5 is a perspective view of the finished product, and Fig. 5 is a perspective view of the finished product.
FIG. 1... Chip type capacitor, 2... Capacitor element, 3, 3'... External terminal, 4... Exterior member,
5...Heat reflective layer.

Claims (1)

[Scope of utility model registration request] In chip-type capacitors in which the capacitor element is covered with an exterior member and external terminals are led out, a heat reflective layer made of a heat reflective paint whose main components are metal oxide and stainless steel powder is formed on the exterior member. Features of chip type capacitor.