A surface-mountable linear vibrator includes a hollow cylindrical housing of a predetermined thickness having a space therein. An elastic member is fixed to an inner surface of the housing. A vibrating body includes a yoke fixed to the elastic member to be affected by elastic force in an axial direction...http://www.google.com/patents/US7224090?utm_source=gb-gplus-sharePatent US7224090 - Surface-mountable linear vibrator
