means 87 through air and reflected by the backing material 89 and the second face surface 99 until refracted at the second face surface 99 the backing material 89 assumes the contour of the backing material support means 91 the design shape of the support means 91 and hence the backing material 89 will depend upon the diameter d of the light source means 87 the maximum thickness of the light transmitting body 95 in relation to the diameter d and the desired width of the light egress face surface 97 the desired distribution of light on the light egress face surface 97 can be attained by selecting the angular relation between the backing material 89 and the second face surface 99 in the arrangement of fig1 the surface of the backing material 89 diverges slightly for a first distance outwardly from the light source means 87 and then converges for the remaining distance the divergence causes some light that would otherwise have been delivered to the light egress face surface 97 in the region closer to the light source means 87 to be delivered to the light egress face surface 97 in the region further away from the light source means 87 the backing material support means 91 and hence the backing material contour can have any shape that will produce the desired light distribution at the light egress face surface 97 the backing material contour can be made up of two planar surfaces as shown by fig1 or a plurality of planar surfaces or a continuous curvature also the backing material 89 and support means 91.