Abstract: In an ultraviolet exposure apparatus, substances contained in an atmosphere contacting a lens surface are reduced, the substances generating accumulations on the lens surface. Openings are formed in the wall of a lens barrel to allow the atmosphere to be replaced by a proper gas. The proper atmospheric gas may be a gas not containing oxygen such as a nitrogen gas, or clean air obtained by intentionally generating accumulations by applying ultraviolet light to source air. A ultraviolet light source is preferably cooled by a cooling system different from the cooling system of a lens optical system.

Abstract: A protective material for electronic parts comprises monoalkylated phenol.formaldehyde novolak resin having 6 to 12 carbon atoms in the alkyl group, and a process for the production of electronic parts, which comprises the following steps A to C:A. covering a device side surface of a semiconductor plate on which semiconductor elements and so forth are mounted with a protective film of a protective material comprising monoalkylated phenol.formaldhyde novolak resin having 6 to 12 carbon atoms in the alkyl group;B. finishing the other or backside surface of the semiconductor plate, not covered with the protective film, to reduce the thickness of the plate; andC. removing the protective film with a solvent.

Abstract: An automatic gas distributing device delivers gas at a constant predetermined pressure from one of a plurality of high pressure vessels arranged in a ring connection. The device has flow paths corresponding to the high pressure vessels, and is controlled by the direct application of pressures of the gas contained in the associated vessels to the relevant stop valves. The device automatically sets into operation a high pressure vessel having a lower gas pressure than other vessels. The device interrupts the high pressure vessel in operation when the gas pressure of the vessel is reduced below a control pressure, and actuates the succeeding vessel.