Abstract: An illuminated sign comprises two or more panels and a frame. The frame is positioned between the panels, so that the frame and the panels form a housing. A pattern made of a colored material, a light scattering material, a light reflecting material, or a combination of the above in various color is coupled to at least one of the panels and positioned inside the housing. LEDs are placed inside the housing to illuminate the pattern. The panels are made of transparent material. The frame can be an integral part of the front and rear panel.
Abstract: A method and a circuit for driving light emitting diodes (LEDs) in multiphase are provided. A string of LEDs divided into groups connected to each other in series is provided. Each group is coupled to ground through separate conductive paths. A phase switch is provided in each conductive path. Increasing the input voltage turn on the string of LEDs, group by group in the sequence downstream the string. To reduce power dissipation, the phase switch of an upstream group is turned off when next downstream group is turned on.