Eugene Michael Lang (March 16, 1919 – April 8, 2017) was an American philanthropist who founded REFAC Technology Development Corporation in 1951. REFAC held patents relating to liquid crystal displays, automated teller machines, credit card verification systems, bar code scanners, video cassette recorders, cassette players, camcorders, electronic keyboards, and spreadsheets, and filed thousands of lawsuits against other corporations to secure licensing fees or out-of-court settlements, a business practice often criticized as patent trolling. He was also the chairman of the board at Swarthmore College.