JPH0314035Y2 - - Google Patents

Description

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

In recent years, as electronic devices have become smaller, the electronic components used in them have also become smaller and more chipped.
Capacitors are no exception.

Generally, 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. , 3′ are connected;
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 1 into an electronic device, when soldering is performed by a reflow method in which the chip capacitor 1 is placed on a printed circuit board and passed through a high-temperature atmosphere, the thickness of the exterior member 4 that covers the capacitor element 2 is Since it is thin, a large amount of heat is applied to the capacitor element 2. For example, when the capacitor element 2 is a plastic film capacitor, the capacitance changes as the plastic film shrinks and deforms due to the above-mentioned thermal influence, and in severe cases, the plastic film is damaged and insulated. Deterioration and short circuits occur, which significantly deteriorate the electrical characteristics and reliability of the chip type capacitor 1.

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

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 large thermal effects, and the electrical The purpose is to provide a chip type capacitor with good characteristics and high reliability.

The above purpose is to provide a chip type capacitor in which a 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 shielding layer that also serves as a display label consisting of a heat insulating layer with excellent heat resistance and a metal heat reflective layer laminated on the surface of this heat insulating layer. It is something.

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. 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 metallicon to both end faces.
A pair of external terminals 3, 3' formed by punching a metal plate of approximately 0.1 mm are connected, and this is covered with an exterior member 4 of synthetic resin such as epoxy using a mold. Further, the portions of the pair of external terminals 3 and 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. In order to avoid electrical connection with the external terminals 3, 3', the surface of the exterior member 4 where the pair of external terminals 3, 3' are not present, that is,
A heat shielding layer 5 consisting of a heat reflective layer 5a and a heat insulating layer 5b laminated inside the heat reflective layer 5a is formed on the top and side surfaces.

As the heat reflective layer 5a, metal foil such as aluminum is suitable, and as the heat insulating layer 5b,
For example, a thin cloth made of glass fiber or the like is suitable, and a heat reflective layer 5a is laminated on the surface of the heat insulating layer 5b to form the heat shielding layer 5, and an adhesive is applied to the heat insulating layer 5b side. The heat shielding layer 5 can be easily formed by depositing it on the exterior member 4 of the chip-type capacitor 1.

In addition, on the heat reflective layer 5a of the heat shielding layer 5,
By printing an arbitrary symbol 6 such as a mark, control symbol, or other symbol in advance and using it as a display label, it is possible to omit the step of stamping ratings, etc. in the manufacturing process of chip capacitors. Become. Further, as the heat insulating layer 5b, SiO ₂ ,
Special heat insulating ceramics mainly composed of Al ₂ O ₃ etc., polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate,
Thermoplastic resins with low thermal conductivity and excellent heat resistance, such as nylon, are also suitable. In this case, the heat insulating layer 5b
If it is formed in advance into a substantially U-shaped cross section, and the surface is coated with aluminum foil or vapor-deposited with aluminum as the heat reflection layer 5a to form the heat shielding layer 5, it is easy to incorporate it onto the exterior member 4. This can be done.

However, when heat irradiation is applied to the chip type capacitor 1, most of the heat from the heat source is reflected by the heat reflective layer 5a, and some of the heat that is absorbed by the heat reflective layer 5a and conducted inside is as follows. Heat insulation is provided by the heat insulating layer 5b located below the heat reflecting layer 5a, so that heat conduction to the capacitor element 2 is extremely small.

In order to measure the effect of this invention, the thickness is 1.5 μm and the width is
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°C, 10 seconds) was conducted using chip-type capacitors with a 0.8 mm epoxy exterior, with the heat shield layer 5 formed according to the present invention, and with the heat shield layer 5 not formed. At the end of the day,
The capacitance change rate in the case where the heat shield layer 5 was formed was several tenths or less of that of the case where the heat shield layer 5 was not formed, 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. Furthermore, in this embodiment, an example using a plastic film capacitor element was shown, but the invention is not limited to this, and a chip type capacitor using other capacitor elements such as an electrolytic capacitor element may also be used. The same applies.

As detailed above, the chip-type capacitor of the present invention has a heat insulating layer with excellent heat resistance on the surface of the exterior member excluding the surface from which external terminals are led out, and a metal heat-resistant layer laminated on the surface of this heat insulating layer. Most of the applied heat is reflected by the heat reflection layer, and some of the heat that is absorbed by the heat reflection layer and transmitted inside is reflected by the heat shield layer. Since the heat conduction to the capacitor element is extremely small, there is no risk of reduction in capacitance or insulation deterioration, resulting in good electrical characteristics and high reliability. .

Furthermore, by making the heat shielding layer double as a display label with ratings etc. printed in advance, there is no need for the stamping process of ratings etc. in the manufacturing process of chip capacitors, thereby reducing manufacturing costs. This makes it possible to provide an inexpensive chip type capacitor.

[Brief explanation of the drawing]

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 shielding layer, 5a... Heat reflective layer, 5b... Heat insulating layer, 6... Symbol.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a chip-type capacitor in which a capacitor element is covered with an exterior member and external terminals are led out, the surface of the exterior member excluding the surface from which the external terminals are led out has a heat-resistant A chip-type capacitor characterized by forming a heat shielding layer that also serves as a display label consisting of a heat insulating layer with excellent heat resistance and a metal heat reflective layer laminated on the surface of the heat insulating layer. (2) The chip-type capacitor according to claim 1, wherein the heat reflective layer is a metal foil. (3) The chip-type capacitor according to claim 1 or 2, wherein the heat insulating layer is made of glass fiber.