LED luminous letter (or caption machine) adopts light emitting diode as lighting source. It is usually installed on the top of buildings or on wall surface in the shape of given letters or signs. LED luminous letter chooses high brightness LED chips and uses specific system to take control of the dynamic video of the letters or signs. The unique designed LED luminous letter surpasses the traditional outdoor advertisement in function. Its abundance colors make it much superior than traditional neon light and make break through in application variety.