Enhanced colour conversion and collimation of micro-LED devices

A pixel comprising a sub-pixel 100 is disclosed, comprising: an LED layer 110 which emits pump light having a pump wavelength; a container layer 420 defining a container volume in which a colour converting layer 130 is provided to receive pump light and emit converted light of a converted wavelength; a lens 140 having a convex surface 141 provided on the container layer; and a reflector assembly conforming to the convex surface comprising a first reflector 142 configured to reflect light at the pump wavelength and transmit light at the converted wavelength, and a second reflector 143 configured to reflect light at both the pump wavelength and the converted wavelength. The second reflector comprises a reflector aperture filled by the first reflector. Unconverted pump light is reflected, and converted light may only be emitted through the reflector aperture, thereby increasing colour saturation and collimating the emitted light beam. The pixel may comprise second and third sub-pixels (200, 300, Figure 3B). The first reflector may comprise a distributed Bragg reflector, and the second reflector may comprise a metallic material.