Abstract: An exposure arrangement for use in a computer-aided design system to produce masks. The arrangement includes a cathode-ray tube which produces an image of the mask on the screen of the tube, and an optical system which projects the image of the mask onto a substrate which is to be exposed. The cathode-ray tube is a high-brightness tube in which the screen is provided with a phosphor which emits in an ultraviolet spectrum and with a cooling circuit for the phosphor. The optical system is designed for use in the ultraviolet spectrum and operates on the ultraviolet image provided by the screen of the high-brightness tube.

Abstract: The invention relates to luminescent screen comprising an optical fibre plate formed by the reunion of elementary optical fibres constituted by bars of core glass (10) enveloped by a cladding glass (12), the optical fibre plate being provided with cavities obtained after having hollowed out partially the core glass. The bottom of the cavities is covered by a deposit of a restoring material (30) which is transparent to the luminous flux, improving the surface state and the flatness of the bottom of the cavities and tending to minimize the break (32) at the intersection between the bottom and the wall of each cavity. The restoring material preferably has an optical index near that of the core glass in order to ensure the optical continuity. Said screen of high resolution and high luminous efficiency is used in display tubes such as night-vision tubes, X-ray converter tubes, slid scanning tubes, cathode ray tubes used in oscilloscopy or in television.