| 摘要 |
1531480 Reflective coatings R B BAGSHAW 5 Dec 1975 [20 Dec 1974 2 April 1975] 49925/75 Heading B2E [Also in Divisions El and G5] Retroreflective signs 27, or road markers 21-24, are made by embedding three-dimensional shapes, such as 47, 48, 50, 51 in Fig. 3b, in a resin or paint carrier 46 so that up to 0.25 inch of each shape projects from the surface coated with the carrier, each of the shapes having surfaces inclined to the surface and covered with retroreflective material to reflect light even at angles of incidence greater than 45‹. The shapes may be made by folding triangular pieces of retroreflective sheet comprising glass beads 63, Fig. 5, resting in dimples on a metal foil 62 with a paper or plastics backing 60, the beads being covered with a transparent, possibly coloured, layer 64 with a refractive index substantially that of water. The glass beads have a refractive index between 2.0 and 2.9. Again, the shapes may be formed as in Fig. 7, folding and combining three tapes 81, 82, 83 of the retroreflective sheet into a three-legged strip 87 which is cut into elements 91. Another form of shape may have a solid core of resin 102 surfaced with the retroreflective sheet 101, Fig. 11. Again, the solid shapes may comprise a clear resin of refractive index 1.338 to 1.70 in which the glass beads are embedded. The solid material may be used to make road marker studs, with or without hollow portions. |
