US Patent 8931906 Light emitting unit array and projection system

A light emitting unit array including a plurality of micro-light emitting diodes (μ-LEDs) is provided. The micro-light emitting diodes are arranged in an array on a substrate, and each of the micro-light emitting diodes includes a reflection layer, a light emitting structure, and a light collimation structure. The light emitting structure is disposed on the reflection layer, and includes a first type doped semiconductor layer, an active layer, and a second type doped semiconductor layer that are stacked sequentially. At least a portion of the first type doped semiconductor layer, the active layer, and the second type doped semiconductor layer are sandwiched between the reflection layer and the light collimation structure.