Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package
Reexamination Certificate
2003-03-05
2004-07-20
Nelms, David (Department: 2818)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
C257S712000, C257S714000, C257S778000
Reexamination Certificate
active
06765285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power semiconductor device having a structure in which at least one discrete semiconductor device is disposed in a case.
2. Description of the Background Art
In a background-art power semiconductor device, a resin-sealed power semiconductor element is mounted on a cooling fin with grease interposed therebetween, to radiate the heat of the power semiconductor element (see e.g., Patent Document 1).
<Patent Document 1> Japanese Patent Application Laid Open Gazette No. 2001-250911.
The background-art power semiconductor device, however, has a problem that it is impossible to ensure sufficient heat radiation since the thermal conductivity of grease is low.
Further, since the flatness of a surface for mounting the fin has a great influence on the heat radiation, the fin mounting surface needs high-level flatness and this raises a problem that the manufacturing cost increases.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a power semiconductor device which allows an increase in radiating efficiency of a power semiconductor element and reduction in manufacturing cost.
The present invention is intended for a power semiconductor device. According to the present invention, the power semiconductor device includes a hollow case and a discrete semiconductor device having a terminal for external connection. The discrete semiconductor device is fitted in the case to be positioned and disposed on a predetermined portion inside the case with the terminal protruding outside from the case. A space defined by a surface of the discrete semiconductor device and an inner wall of the case forms a duct for a coolant used for cooling the discrete semiconductor device which is immersed therein.
The discrete semiconductor device is immersed in the coolant. Therefore, the discrete semiconductor device can be directly cooled by the coolant and this enhances the cooling efficiency of the discrete semiconductor device.
Further, the discrete semiconductor device is fitted in the case to be positioned and disposed on a predetermined portion inside the case. This enhances the mounting accuracy of a control circuit substrate and the like.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4928207 (1990-05-01), Chrysler et al.
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patent: 5198889 (1993-03-01), Hisano et al.
patent: 5672548 (1997-09-01), Culnane et al.
patent: 6313520 (2001-11-01), Yoshida et al.
patent: 2002/0185718 (2002-12-01), Mikubo et al.
patent: 60-37756 (1985-02-01), None
patent: 61-59741 (1986-03-01), None
patent: 2-166758 (1990-06-01), None
patent: 10-51169 (1998-02-01), None
patent: 2001-250911 (2001-09-01), None
Shinohara Toshiaki
Yoshida Takanobu
Mitsubishi Denki & Kabushiki Kaisha
Nelms David
Nguyen Dao H.
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