Abstract: Disclosed herein are techniques for micro-light emitting diodes (micro-LEDs). According to certain embodiments, a micro-LED device includes a micro-LED comprising a semiconductor mesa structure configured to emit light, a spacer layer on the micro-LED, and a micro-lens on the spacer layer and configured to extract and collimate the light emitted by the micro-LED, where a thickness of the spacer layer is selected such that a focal point of the micro-lens is at a front surface of the semiconductor mesa structure.

Abstract: A micro-light emitting diode includes a semiconductor mesa structure that includes at least a portion of an n-type semiconductor layer, an active region configured to emit visible light, and a p-type semiconductor layer. The micro-LED device also includes an insulator layer that includes an undoped semiconductor passivation layer grown on sidewalls of the semiconductor mesa structure, and a dielectric passivation layer characterized by a refractive index lower than a refractive index of the undoped semiconductor passivation layer. The micro-LED device further includes a reflective metal layer deposited on the dielectric passivation layer, and a micro-lens configured to collimate the visible light emitted by the active region, where a ratio between a width of the micro-lens and a width of the active region may be greater than about 1.5.

Abstract: An optical structure is disclosed for use in an augmented reality display. The structure includes a waveguide (52) and an input diffractive optical structure (54) configured to receive light from a projector and couple the received light into the waveguide (52). An output diffractive optical structure (60) is configured to receive light from the input diffractive optical element (54) in an input direction, wherein the output diffractive optical structure comprises at least a first diffractive optical element (30) and a second diffractive optical element (32) with different respective diffraction efficiencies, wherein the first diffractive optical element has a relatively high diffraction efficiency and the second diffractive optical element has a relatively low diffraction efficiency and the first and second diffractive optical elements are overlaid on one another in or on the waveguide. The output diffractive optical structure (60) comprises a first portion (62) and a second portion (64).