In display projection applications, micron scale light emitting diode (μLED) array displays present an alternative toconventional lamps as light sources, with the advantage of higher efficiency and smaller form factor (particularly if thearray is monolithic). However, μLEDs without inbuilt optics produce an emission pattern similar to a Lambertiandistribution. By employing a pair of microlens arrays aligned to the μLED array to collimate the light, and a relay lens tofocus the light onto a display panel, we can produce a display that both serves the same function as a traditionalilluminator such as one which might be found in an LCOS or a DMD display, and utilises the addressing of the array togenerate light over the desired display area only (zoning), rather than having the entire array be illuminated when thedisplay is active. Using raytracing, we find that such system is limited by the performance of small μLEDs needed andthe manufacture of the associated micro-optics.
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