| 摘要 |
The invention provides a durable multipurpose screenboard especially adapted for both the screening of projected images and for writing thereon, wherein the screenboard comprises an upper section, a core section and a base section, the upper section comprising at least two superposed layers of transparent overlay sheets, each of the sheets weighing between 20 and 120 grams per square meter and having been soaked in a solution or melt of a polymeric resin material to subsequently form an intermediate solid plastic layer, the upper surface of the upper sheet being roughened by a plurality of closely-spaced complementary depressions of depth between 0.01 mm and 0.2 mm, the core section comprising at least one paper sheet weighing between 60 and 140 grams per square meter and having been soaked in a solution or melt of a polymeric resin material to subsequently form an intermediate solid plastic layer, and the base section comprising a plastic sheet, the screenboard having a surface being adapted to both reduce glare of projected images and to erasably retain particles from writing implements pressed therealong.
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