Electricity: electrical systems and devices – Electrostatic capacitors – Fixed capacitor
Reexamination Certificate
1999-04-28
2001-03-13
Dinkins, Anthony (Department: 2831)
Electricity: electrical systems and devices
Electrostatic capacitors
Fixed capacitor
C361S309000, C361S321200
Reexamination Certificate
active
06201683
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ceramic electronic part and to a mounting structure therefor, and more specifically relates to an improvement in a terminal portion of a ceramic electronic part having a ceramic electronic component such as a monolithic ceramic capacitor.
2. Description of the Related Art
When a ceramic electronic part, having a ceramic electronic component, such as a monolithic ceramic capacitor, in which terminals are formed on both sides thereof, is mounted on a substrate, the ceramic electronic part is liable to cause mechanical damage to the ceramic electronic component, such as cracks due to thermal effects caused by the substrate. Such damage is especially prone to occur when a heat-producing component is located adjacent thereto, or if the substrate is made of aluminum having a high heat-dissipation rate.
In these cases, temperature differences in the ceramic electronic component of the ceramic electronic part are produced one or more times, resulting in mechanical failure of the ceramic electronic component. In particular, when the ceramic electronic component is mounted on an aluminum substrate, relatively large stresses are exerted on the ceramic electronic component by the substrate due to the large thermal expansion difference between the aluminum substrate and the ceramic electronic component, during temperature increase or decrease, similarly resulting in mechanical failure of the ceramic electronic component.
To solve the above-mentioned problem, a metal terminal member is connected to the terminal formed on the ceramic electronic component, and the ceramic electronic component is mounted on the substrate via the terminal member. This terminal member reduces the thermal conduction to the ceramic electronic component from the substrate and also alleviates the stresses exerted on the ceramic electronic component, absorbing the thermal expansion difference between the substrate and the ceramic electronic component by its own deformation.
However, the terminal member has not proved sufficiently effective in preventing mechanical failure of the ceramic electronic component under certain conditions. When thermal conditions are extreme for the ceramic electronic component in particular, mechanical failure often occurs.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a ceramic electronic part and a mounting structure therefor which is capable of solving the above-mentioned problems.
In accordance with one aspect of the present invention, a ceramic electronic part comprises a ceramic electronic component having a terminal formed at an end thereof and a terminal member formed of a metal plate which comprises a connecting portion for connecting to the terminal, an intermediate portion, and a fitting portion for connecting to a substrate sequentially along a length of the terminal member from one end to the other thereof, the terminal member being connected to the terminal via the connecting portion, wherein length of the intermediate portion measured along the length of the terminal member is at least 5 mm.
In a ceramic electronic part according to the present invention, the length of the intermediate portion may be equal to or less than 10 mm.
In a ceramic electronic part according to the present invention, the thermal conductivity of the terminal member may be equal to or less than 0.3 cal/cm/sec/° C.
In a ceramic electronic part according to the present invention, the degree of radiation of the terminal member may be at least 0.03, provided that the blackbody radiation-degree is 1.
In accordance with another aspect of the present invention, a ceramic electronic-part mounting structure comprises a substrate and a ceramic electronic component mounted on the substrate, the ceramic electronic component having a terminal formed thereon and further comprising a terminal member formed of a metal plate in which one end thereof is connected to the terminal, wherein a length of the terminal member between the ceramic electronic component and the substrate measured along the length of the terminal member is at least 5 mm.
REFERENCES:
patent: 1611183 (1926-12-01), Frasse
patent: 4158218 (1979-06-01), McLaurin et al.
patent: 2327631 (1999-02-01), None
Nakagawa Takuji
Yamada Masayuki
Dinkins Anthony
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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