| 摘要 |
<p>1,237,201. Coated products. GAF CORP. 17 Jan., 1969 [19 Jan., 1968], No. 2910/69. Heading B2E. [Also in Divisions G2 and G3] A rear projection screen comprises a transparent base coated on one face with a mixture of finely divided 2 to 6 micron particles of amorphous silica having capillary passages therein in a transparent organic material, silica being in the proportion of 1%-5% by weight. The transparent organic material may be a nitrocellulose lacquer, or a composition of 15% vinyl resin, 3% cyclohexanone, 61% di-isobutyl ketone, 10% xylol, 10% methyl isobutyl ketone, and 1% plasticizer such as di-butyl-phthalate. The silica is initially prepared as a concentrated mixture which is subsequently diluted with more lacquer for spraying on to the base. The base may be of polymethyl methacrylate, glass or polystyrene in which latter case the lacquer is a vinyl or acrylic emulsion.</p> |
