A highly efficient solar focusing means being hollow and in semi-cylindrical or arcuate shape, the surface of which has such fine menisci as to act like convex lenses to focus solar rays towards the center of the focusing body, irrespective of the position of the sun, where a solar energy conversion...http://www.google.fr/patents/US4299201?utm_source=gb-gplus-shareBrevet US4299201 - Solar energy focusing means
