a motion sensing device for sensing infrared rays includes a substrate ; an optical module , including a first spacer layer , coupled to the substrate ; a first glass layer , formed on the first spacer layer ; a second spacer layer , formed on the first glass layer ; a second glass layer , formed on the second spacer layer ; a third spacer layer , formed on the second glass layer ; a first lens , bonding on a first side of the second glass layer ; and a second layer , bonding on a second side relative to the first side of the second glass layer ; and a coating layer , covered on the optical layer for shielding the infrared rays , wherein the coating layer does not cover the first lens .