JPS59197120A - Ultrafine film condenser - 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 (1) Description of the technical field and application to which the invention pertains The present invention relates to a micro film capacitor, and in particular to a hybrid I
The present invention relates to chip-type microfilms and capacitors that are mounted on C and high-density wiring boards, etc.

(2) Description of conventional technology In response to the trend toward smaller and thinner devices, monolithic ICs
Many chip components are used in unachieved areas and areas where flexibility is required.

However, when it comes to capacitors, most of them are ceramic chip capacitors and tantalum chip capacitors.) Capacitors using organic films require strict soldering conditions due to the low heat resistance of the material. It had the disadvantage of not being suitable. For this reason, it has been investigated that the heat resistance can be improved by adding an outer casing, but in chip capacitors aimed at miniaturization, it is not possible to increase the thickness of the outer casing, and the dielectric constant of the organic film dielectric is higher than that of ceramic or solar oxide. Since the diameter is more than one order of magnitude larger, it is also at a disadvantage in terms of size when it comes to downsizing.

(3) Purpose of the Invention The purpose of the present invention is to improve these conventional drawbacks by arranging a heat insulating material on the outermost layer of the element in a micro film capacitor in which organic films are wound or laminated. It is characterized by its exterior. Another feature is that the lead-out portion of the electrode from the micro film capacitor element to the external terminal is formed of a material with low thermal conductivity or a lead material with a small cross-sectional area perpendicular to the direction of heat conduction. Furthermore, it is characterized by having a terminal made of a conductive material with a metal thin film formed on the surface of a metal material or insulating material with low thermal conductivity.

The present invention will be explained below with reference to the drawings.

(4) Description of structure and operation of the invention FIG. 1 is an exploded perspective view illustrating a conventional wound structure capacitor element. It consists of Figure 2 shows an embodiment of the present invention, and Figure 1 shows a capacitor element with a conventional structure, in which the outermost layer has a thickness of 30 to 300 μm.
A heat insulating material 2 with a thickness of m (microns) is arranged to form the element 3.

The heat insulating material 2 must be an insulating material, and glass cotton, asbestos, felt, wood, kraft paper, etc. are suitable, but a plastic film on which metal is not vapor-deposited may also be used.

When using a plastic film, it is generally suitable to use a film of the same type as the element dielectric material from the viewpoint of workability, or a film with higher heat resistance than the element dielectric material from a thermal viewpoint. There is.

The first implementation side chain 3 of the present invention shows a structure in which a heat insulating material 2 is disposed on the outermost layer and the element 3 is covered with a resin and assembled into a micro film capacitor (chip capacitor). Reference numerals 4al and 4b are terminal caps from which electrodes of the element are drawn out, and 5 is an insulating part of the main body made of epoxy resin or the like. Figure 4 is an exploded perspective view of Figure 3.
After packaging the element 3 in a certain shape with epoxy resin or the like and forming the main body insulating part 5, the exposed electrodes of the element 3 and the terminal caps 4a and 4b are bonded with conductive adhesive such as Ag-Pd paste. This figure shows that the chip capacitor of the first embodiment of the present invention is made by fitting and connecting through a material. The terminal caps 4a, 4b and the electrodes of the element 3 may be connected by soldering, but a conductive adhesive or the like having low thermal conductivity is more suitable.

When this type of chip capacitor is normally mounted, it is temporarily fixed with an adhesive so that the terminals are positioned on the land of a printed wiring board or alumina board, and then the whole is immersed in a jet floater and soldered. be attached. In the capacitor of the first embodiment, the outermost layer of the heat insulating material 2 and the conductive adhesive with low thermal conductivity effectively act as a heat insulating layer against the severe thermal conditions during mounting. When the dielectric is a metallized polyethylene terephthalate film, the capacitance changes within ±1% with respect to the soldering conditions at a temperature of 270°C for 10 seconds, and tan δ is below the initial specified value o, o o s. there were.

FIG. 5 shows a second embodiment of the present invention. FIG. 6 is an exploded perspective view of FIG. 5.

The chip capacitors shown in Figs. 5 and 6 are improved versions of the first embodiment shown in Figs. Instead of using conductive adhesive, lead wires 6a+6b are used.

This is because even if a conductive adhesive with low thermal conductivity is used, as the device ages, the cross-sectional area of the heat conduction path becomes large.
Even when the terminal cap is heated, the heat escapes toward the element, so it takes time for the temperature to rise. By the time the terminal cap surface temperature reaches the solder melting temperature of around 200°C, the element temperature has also reached the film's heat resistance temperature. This is because the price will be higher than that.

In FIGS. 5 and 6, if the cross-sectional area of the lead wires 6a and 6b is appropriately selected, the amount of heat conduction can be suppressed to a constant amount in proportion to the cross-sectional area. Practically 0.4~Q, 5 m
It has been found that a lead wire with a diameter of m is sufficiently effective. If the lead wires 6a and 6b are used, the electrodes of the element and the terminal cap are connected via these lead wires, so there is no need to bring the surface of the terminal cap close to the electrode of the element, and the main body made of epoxy resin etc. Thermal insulation can be achieved by making the insulating portion 5 sufficiently thick. For further perfection, place insulation material on the inner surface of the terminal cap.
It is preferable to fit it into the capacitor main body insulating part 5.

Further, the leads from the electrodes of the element are not wire rods as shown in the lead wires 6al and 6b in FIG. 6, but plate leads may be used, and they may also serve as terminals as shown in the lead plate leads 7al and 7b in FIG. can.

Although FIG. 7 alone can be used as a finished chip capacitor as the third embodiment, it is also possible to add a terminal cap to this product to obtain a product as the fourth embodiment as shown in FIG. It is also possible to use a material with low thermal conductivity for the plate-shaped leads shown in Figure 7 and the terminal caps shown in Figures 3 to 8 to reduce the heat conduction cross section. It goes without saying that materials and leads with small heat conduction cross sections may be used together to enhance the synergistic effect. do not have.

A fifth embodiment of this type of the invention is shown in FIG. The cross-sectional area of the drawer lead wires 9a and 9b is small and the wire diameter is Q, 4
The terminals 8a+sb, which are formed by means such as electroless plating on the ends of the capacitor body insulating part 5, are made by chemically forming a metal film on the surface of an epoxy resin with low thermal conductivity. It is formed by special processing. For this reason, the temperature of the terminal can be easily increased with a small amount of heat, so it can be easily soldered and mounted. Output lead wires 9a, 9b
and the plated terminals 8a, 8b are electrically connected at a connecting portion 10 at the intersection. This connection is made by solder dipping the terminals to apply pre-soldering to the entire plated terminals 8a+8b.

Although an element with a wound structure as shown in FIGS. 1 and 2 has been described as an embodiment of the present invention, the same idea applies to an element with a laminated structure, and in that case, the outermost layer is a laminated layer. Depending on the size of the margin region where there is no electrode pattern, the side surfaces of the top and bottom layers can have the same effect as placing a heat insulating material there. Furthermore, it goes without saying that the predetermined thickness of the heat insulating material may be formed by stacking or winding thin layers of 2 .mu.m to 12 .mu.m.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional capacitor element structure. Second
The figure is a perspective view of a capacitor element showing one embodiment of the present invention.
3, 5, 7, 8 and 9 are partial perspective views showing each embodiment of the present invention, and FIGS. 4 and 6 are each of FIGS. 3 and 5. It is an exploded perspective view showing how to assemble an example. Explanation of symbols 1! 1a+ lb...Dielectric film, 2.
...Insulation material, 3 ... (capacitor) element, 4a, 4b, 4C14d ... terminal cap,
5... Body insulation part, 6a, 6b... Outer lead wire, 7a+7b... Outer plate lead, 8a, 8b... Plated terminal, ga, gb・
...Output lead wire, 10...Connection part.躬 ,,3 Figure 44 4th figure outside S figure C 46' S4ρ Atsugu figure

Claims (3)

[Claims] (1) A micro film capacitor formed by winding or laminating organic films, characterized in that a heat insulating material is disposed on the outermost layer of the element and the element is packaged with a plastic resin. (2) The lead-out portion of the electrode from the capacitor element to the external terminal is made of a material with low thermal conductivity or made of a material having a small cross-sectional area orthogonal to the direction of heat conduction and is obliquely formed on the lead side. The micro film capacitor described in (1). (3) Table of metal or insulating materials with low thermal conductivity■
(1) A micro film capacitor according to the present invention, characterized in that the micro film capacitor (1) has a terminal made of a conductive material on which a metal thin film is formed.