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, a partially transparent face thereon, tubing mounted therein and having an inside radius (r), and a plurality of concavely-curved, reflective channels each having an angle of wrap (.beta.) and positioned at a minimum distance (d) from the luminous tubing; wherein the improvement comprises each channel being substantially semi-cylindrical and having a radius (R) approximately equal to 80 to 120% of r.times.(1+1/(sin .alpha.))+d.
A direct-type back light device includes a plurality of luminescent lamps, a rectangular frame having holes formed along opposing sides with the luminescent lamps inserted into the holes, a reflecting plate formed at a bottom surface of the rectangular frame, and at least one lamp holder attached to the reflecting plate and supporting the luminescent lamps.
