Abstract: Provided is a thermosetting resin composition that can satisfy both low transmission loss and radiation performance even under the same curing conditions as those for conventional substrate materials for high-frequency applications, and also provided are an adhesive sheet, a prepreg, and a laminate. The thermosetting resin composition comprises a maleimide compound having at least two maleimide groups per molecule, a polyphenylene ether compound having at least two reactive organic groups per molecule, a curing accelerator, and an inorganic filler, wherein the inorganic filler is low-sodium aluminum oxide, and the low-sodium aluminum oxide has an Na+ ion content of 10 ppm or less.

Abstract: [Problems] White laminates for print wire boards heretofore have problems of discoloring of thermosetting resin portion and reduction of reflectance. In LEDs of type using UV emitting device have not been appropriate in mounting recent high luminous intensity LED, a requirement for substrates which are not discolored towards UV and heat is becoming strong, since substrates on which the LED chip is mounted are deteriorated and discolored by UV. Further, in mounting chip LED, accuracy of board thickness is also required in order to avoid liquid leakage during sealing process of the chip LED. [Means for Solving the Problems] White prepreg according to the present invention is characterized in that it comprises a dried product of a resin composition (E) impregnated on a sheet glass fiber substrate; said composition (E) containing, as essential ingredients, an epoxy resin (A) comprising a cycloaliphatic epoxy resin (A1), a glycidyl (meth)acrylate polymer (B), a white pigment (C), and a curative (D).

Abstract: An entry board for drilling improves drill machinability such as hole positional accuracy using a fine-diameter drill, and roughness of the walls of the drilled holes. The entry board has a metallic foil, and a thermosetting resin is covered on one or both sides of the metallic foil to provide a drill-penetrating layer.

Abstract: In manufacturing multilayer printed wiring boards with a cavity for mounting an electronic device, a rubber or composite rubber sheet is mounted in the cavity to prevent a prepreg resin from flowing into the cavity. The rubber sheet or composite rubber sheet is removed after applying pressure and temperature to an assembly consisting of boards to be bonded and the prepreg between them. This eliminates poor bonding which can result when resin flows into the cavity.

Abstract: A molded capacitor has capacitor elements mounted in respective inner casings filled with an insulating fluid. The capacitor elements in the inner casings are connected together to form an assembly, and the assembly is molded together in an outer housing. The inner casings may be separately molded, with the assembly of the molded inner casings containing the capacitor elements molded again to form the outer housing. The assembly may also be housed in an outer casing with an insulating gas sealed therein.

Abstract: A test device for burn-in tests of semiconductor packages. The device includes a printed circuit board provided with openings or frames for receiving the semiconductor packages to be tested and aligning the package lead with circuit board terminals. A cover plate provided with elastic bodies on a back side thereof is used to concurrently elastically press all of the leads and terminals into electrical contact. In one embodiment, elastic connectors having thin metal wires embedded therein are provided in the openings or frames to electrically connect the leads to the terminals when the cover plates is pressed downwards on the semiconductor packages.

Abstract: The present invention relates to a resin molding compound for sealing electronic parts.In general, electronic parts are sealed in ceramic packages or synthetic resin molding compounds in order to protect them from an external circumstance in the use thereof.In many cases, materials consisting of synthetic resins and inorganic fillers mainly comprising silicon oxide have been used as sealing materials for synthetic resin molding compounds.However, a defect has occurred in that since an infinitesimal quantity of radioactive elements such as uranium and thorium is contained in inorganic fillers, a memory element in electronic parts produces misactions by alpha-rays radiated from radioactive elements according to circumstances and thereby the fidelity of electronic parts is greatly influenced.

Abstract: An improved high-tension capacitor is proposed which uses no insulation oil or gas. Not only the dielectric layers in the capacitor elements are impregnated with synthetic resin, but also the capacitor elements are insulated with synthetic resin by impregnating the insulation material around the capacitor elements with synthetic resin. The insulating layer around the capacitor elements is formed with a plurality of air ducts.

Abstract: A high-tension capacitor including alternating dielectric layers and electrode layers, the dielectric layers having a synthetic resin film between a layer of highly impregnable and porous material. The capacitor elements having the alternating electrode layers and dielectric layers are surrounded by a highly impregnable electrically insulating material and the assembly is impregnated with a synthetic resin which penetrates the porous layers of the dielectric layers and the insulating material surrounding the capacitor elements. Alternatively, the capacitor elements are impregnated with a resin having a good impregnability and low viscosity and the insulation layer molded around the impregnated capacitor elements can be impregnated with a resin having good strength and high viscosity. A relaxation layer may also be interposed at regular intervals between the electrode layers and dielectric layers for absorbing the shrinking force upon hardening of the synthetic resin.