Light-collecting illumination systems are disclosed, which include a light source module, a first meniscus lens having a convex side and a concave side and a second meniscus lens having a convex side and a concave side. The concave side of the second meniscus lens is adjacent to the convex side of the...http://www.google.com.tw/patents/US7427146?utm_source=gb-gplus-share專利 US7427146 - Light-collecting illumination system
