Abstract: A shadow mask is applicable to forming a minute film on a substrate by evaporation or the like. The shadow mask comprises a support film, a stopper film, a polyimide film and a thin plate. The support film has enough mechanical strength necessary for forming predetermined sized holes. The stopper film is formed on the support film and is used as an etching stopper while forming the holes in the support film. The polyimide film is formed on the stopper film and bonds the stopper film to the thin plate. The thin plate is formed on the polyimide film and is made of a material which is the same as that of the substrate on which the film is formed or a material whose thermal expansion rate is substantially the same as that of the substrate. Openings of the shadow mask are formed at predetermined regions through the support film, the stopper film, the polyimide film and the thin plate. Each of the openings has a tapered portion and a projected portion.

Abstract: A method of removing liquid from a suspension by concurrently subjecting the suspension to the action of a pulsed electrical field and optionally a concurrent sonic or ultrasonic field so as to remove liquid from the suspension. The suspension is moved into a liquid removal chamber between opposing electrodes one of which is permeable to the liquid. The sonic or ultrasonic field may then be optionally applied to the suspension concurrently with the pulsed electrical field, at a frequency and amplitude adapted to cause liquid to separate from the suspension particles. The concurrently applied electrical field between the electrodes causes the particles to migrate away from the permeable electrode and liquid to migrate toward the permeable electrode. Liquid is then removed through the permeable electrode. The method requires less energy to remove a unit of liquid, has a more advantageous rate of liquid removal and achieves a lower moisture content than if a steady electrical field is applied.