Image-like illumination with LED arrays: design

An array of spatially distributed light-emitting diodes (LEDs) can produce an illumination pattern that approaches an image by individually modulating each LED. In this letter, I analyze the first-order design of such systems in order to achieve the best match between the illumination distribution and a desired image. In particular, simple formulas are given for the optimal number of LEDs, working distance, array size, and LED beam pattern. The analysis developed here may be applied to the design of LED systems such as architecture lighting, energy-efficient lighting, backlight local dimming for displays, and structured illumination microscopy with micro-LED arrays.