Design of a free-form lens for LED light with high efficiency and uniform illumination Quoc Anh, Nguyen Doan ; Lai, Min-Feng ; Ma, Hsin-Yi ; Lee, Hsiao-Yi Abstract Publication: Applied Optics Pub Date: October 2014 DOI: 10.1364/AO.53.00H140 Bibcode: 2014ApOpt..53H.140Q