| 摘要 |
<p>1530630 Retro reflective road studs FERRO CORP 19 Dec 1975 [10 March 1975] 52178/75 Heading E1G A retro reflective device comprises a concave-convex lens 16 having a cube-corner array 20 disposed across its concavity so that a parallel beam of light emerging from the concave surface is reflected back by the cube corners and emerges from the convex surface as a parallel beam of greater width. The cube-corner array 20 in the form of a tape secured to the concave side of the lens 16. The device is attached to a vertical or sloping abutment on a road stud 25. The centres of curvature of the lens may be in the same or different horizontal planes.</p> |
