GB542723A - Improvements in multiple divergence reflex reflecting devices - Google Patents

Abstract

542,723. Reflectors. GARBARINI, A. Aug. 12, 1939, Nos. 23304 and 23305. Convention dates, Aug. 12, 1938 and April 7, 1939. [Class 97 (i)] [Also in Group XL] A reflex reflector, of the kind comprising two part-spherical elements with their bases connected, the rear element reflecting an incident beam from a distant source back through the front element towards the source as a beam of small divergence, is caused to reflect a beam the divergence of which increases with the angle between the incident beam and the axis of the device, by forming one of the elements with two or more spherical, ellipsoidal or helical stepped surfaces of different curvature. As the reflector is approached by a vehicle on one side of its axis the incident rays from the vehicle lights become more oblique to the axis and are reflected back as a beam diverging sufficiently to reach an observer's eye at a distance from the light source which is not negligible, as it is when at a considerable distance from the reflector. Fig. 3 shows one form of reflector, comprising a front lens having a spherical surface of radius r, and a rear element having stepped reflecting surfaces C<SP>1</SP>-C<SP>4</SP> of decreasing radii R<SP>1</SP>-R<SP>4</SP>, all being concentric with the front element. The reflector may be formed as a surface of revolution through 180 degrees of the contour shown about the axis XX or the axis YY. Fig. 5 showing a front view of such a device formed in the first way. Incident rays of increasing obliquity to the axis YY are reflected successively from the surfaces C<SP>1</SP>-C<SP>4</SP> with increasing divergence. In a modification, the front element is stepped and the reflecting element has a single spherical surface. Fig. 13 shows a form to be placed substantially at ground level, a beam incident on the surfaces O, P, Q being reflected back at increasing divergencies as it passes from one to the next. In all cases axial beams, which are to be reflected as beams of small divergence, are brought to a focus at the reflecting surface, and beams oblique to the axis, which are to be reflected as divergent beams, are brought to a focus in front of or behind the reflecting surface. The device may be made of material transparent to fluoro-activating rays, and a fluorescent coating be applied in front of the reflecting layer which is otherwise directly applied to the reflecting surfaces.