Patent ID: 6199310
Filing Date: 2001-03-13
Classification: F21V,F21Y,G09F,Y10S

Abstract:
An illuminated grid sign designed to be viewed at a maximum viewing angle (.alpha.) from a horizontal line of sight of an observer, the sign comprising:a frame having a width;a partially transparent face supported thereon;a plurality of lengthwise sections of luminous tubing mounted in the frame and having a tubing inside radius (r) and an inner surface having a reflector-closest edge, and;a plurality of concavely-curved, reflective channels each having an angle of wrap (.beta.) and a concave surface having a tubing-closest edge positioned at a minimum distance (d) from the tubing inner surface reflector-closest edge;wherein the improvement comprises each said reflective channel having a substantially semi-cylindrical shape with a radius of curvature (R) approximately equal to about 80% to about 120% of r.times.(1+1/(sin .alpha.))+d and an angle of wrap (.beta.) that is no greater than 180.degree..