| 摘要 |
Producing a sheet from a vitreous material by pressing between contra-rotating rolls to reduce at least locally the thickness of the sheet (F) to a predetermined thickness. The thickness of the sheet is reduced progressively by a sequence of successive passes through the contra-rotating rolls (1i, 2i, 3i) whilst maintaining the average viscosity of the sheet between 5.104 and 109 poise, at least before the last pass between the rolls. The sheet is reduced from its initial thickness (e) in a succession of small steps (e1 , e2 , e3 ) in order to overcome problems associated with differential shrinkage. Also claimed are (I) a device consisting of a number of pairs of contra-rotating rolls (1i, 2i, 3i), a set of conveyors (4i ) and heating systems (5I) between the pairs of rolls, and, (II) a control plate for a flat screen for displaying cathode ray images, consisting of a network of electrodes carried by a glass sheet.
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