| 摘要 |
868,179. Etching. COMPAGNIE FRANCAISE THOMSON-HOUSTON. Sept. 25, 1959 [Oct. 23, 1958], No. 32732/59. Class 100(2) A sheet of plastic material, e.g. "Teflon" or "Plexiglass" (Registered Trade Marks) is sprayed with molten metal, e.g. lead, zinc, silver or tin, allowed to cool, coated on its metallised surface with a photosensitive emulsion by means of a roller, allowed to dry, exposed to light through a positive film of a design, developed, and etched by immersion in a solution of a metal salt, e.g. iron perchlorate, thereafter being washed and dried. It is then coated with luminescent or transparent paint for use as an illuminated placard.
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