Abstract: A multi-layer wiring substrate includes an aluminum nitride ceramic substrate, a multi-layer wiring part having an electric insulating layer of an organic polymer, a die pad for mounting thereon an electronic part, and a thermal via of a column shape for effectively dissipating heat generated in the mounted electric part. The multi-layer wiring part is integrally formed on the ceramic substrate. The die pad is provided on a surface of the multi-layer wiring part. One end of the thermal via connects to the die pad, while the other end of the thermal via passes through the multi-layer wiring part and extends at least to the ceramic substrate. The thermal via is electrically insulated from the multi-layer wiring part. In the second multi-layer wiring substrate, at least one of end portions of the above thermal via is wider than a section of the other portion of the thermal via, resulting in further improvement of the heat dissipating property.

Abstract: A heat sink according to the invention comprises a multilayered body prepared by laying one upon the other a plurality of heat sink fin elements having pin-fin sections formed by cutting a number of slits through thin plates of a thermally conductive material with spacers, each being inserted between two adjacent heat sink fin elements to separate them by a given distance.

Abstract: A rotary anode x-ray tube includes a vacuum vessel in which a cathode, an anode target, a connecting rod, a rotor, bearings, and a heat conducting plate are arranged. The cathode electrode emits electrons. The anode target generates x-rays when electrons emitted from the cathode electrode collide with the target. The connecting rod supports the anode target. The connecting rod is constituted by a rod member consisting of a pulverized sintered material. The rotor is mounted on the connecting rod. The anode target is rotatably supported by the bearings. The heat conducting plate is arranged between the anode target and the rotor. A heat conducting plate made of a material having excellent heat conduction characteristics can be arranged between the anode target and the rotor. The connecting rod is manufactured by processes such as plasticization including tube spinning.

Abstract: A cooling apparatus for cooling a heat generating member by removing heat produced in the member comprises a cooling stud which is thermally jointed to the heat generating member, a woking fluid for removing the heat transmitted to the cooling stud by utilizing vaporization thereof, a condenser for condensing the vaporized fluid and providing the liquid phase fluid to the cooling stud, and a passage through which the liquid phase fluid passes while vaporizing to remove the heat, the liquid phase fluid being provided to the passage in the cooling stud by the condenser device.

Abstract: A semiconductor switching apparatus includes a member for radiating heat generated from semiconductor switching element chips and for reducing a thermal stress. The lengths of gate electrode wires are equally set. The semiconductor switching apparatus has a large capacity and good switching characteristics.

Abstract: A cooling apparatus for a housing which is provided with an opening at the upper part thereof, comprises a casing located on the upper part of the housing and including a bottom plate to close the opening and a chamber, a partition wall provided in the casing to divide the chamber into a first chamber section and a second chamber section, heat exchanger including at least one heat pipe provided in the casing through the partition wall with coolant therein for exchanging heat in the first chamber section with heat in the second chamber section. The heat pipe has one end portion in the first chamber section and the other end portion in the second chamber section, and inclines with the one end portion located lower than the other end portion.