| 摘要 |
The improved projection screen of the invention comprises a substrate of extended area upon which has been deposited, as by printing, or casting, in accordance with the method, a pattern of liquid-containing elements of desired shape and size, which are then solidifed as by drying or chilling, in accordance with the method, to permanent light-affecting form. In one embodiment, the liquid includes a thixotropic agent to aid in shape retention during permanent solidification. Such liquid may comprise a polymer such as polyvinyl chloride, or the like, to which has been added a hardening agent and/or slip agent. Permanent solidification can be accomplished by drying, catalysis, temperature reduction or elevation or any other suitable means. In another embodiment, a substrate can be extrusion casted or the like with one surface bearing the desired optical shape, or the surface of a preformed heat deformable substrate can be heated and deformed to the desired optical configuration and then solidified, as by chilling. the solidified optical elements can be in any desired size, pattern, shape and profile thickness and may be transparent or opaque, with or without light-defracting inclusions and/or matte surface portions or the like. The substrate surface to which the elements are attached may be specular, semi-specular, non-specular or transparent and the substrate may be rigid or flexible. The optical elements and/or the substrate can be metallized, if desired. The method is rapid, simple, inexpensive and reproducible and has great flexiblity. The projection screen produced by the method has carefully controlled optical properties which can be tailored for desired applications.
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