The projector uses a laser diode as the light source and then magnifies an image up to 146-inches from as little as 17cm clearance between the rear of the unit and the wall. If pushed up to touching distance, the minimum image size measures 66-inches, diagonally.
http://www.avforums.com/news/ces-2014-sony-announce-short-throw-4k-laser-projector.9754