Nitride micro-display with integrated micro-lenses

We report progress in control of the emission from both parallel-addressed and matrix-addressed micro-array light-emitting diodes (micro-LEDs), using integrated micro-lenses. The integrated matrix-addressed device consists of a 128 × 96 element array with 470 nm emission, aligned to a 128 × 96 element sapphire micro-lens array. The lenses have a diameter of 12 µm, a centre height of 1.8 µm and a measured focal length of 8 µm. The root-mean-square (r.m.s.) roughness of the lenses, as measured by atomic force microscopy (AFM), is better than 3 nm, ensuring high optical quality. The integrated array enables the light emitted from the individual elements to be well-resolved.