US Patent 9443833 Transparent overlapping LED die layers

A first layer of inorganic first vertical LED dies (VLEDs) of a first color is printed on a conductor surface. A first transparent conductor layer is deposited over the first VLEDs to electrically contact top electrodes of the first VLEDs. An electrically insulated second layer of second VLEDs of a second color is printed over the first transparent conductor layer, and an electrically insulated third layer of third VLEDs of a third color is printed over the first transparent conductor layer. For a color display, the VLEDs are printed in an addressable pixel array. Since the VLEDs are printed as an ink, the overlying VLEDs in a pixel are not vertically aligned, so there is little blockage of light. If the structure is used for general illumination, the VLEDs do not need to be printed in pixel areas.