  Digital light projector systems are crucial components in applications
including computational imaging, fluorescence microscopy and highly parallel
data communications. Here we present a chip-scale projector system based on
emissive micro-LED pixels directly bonded to a smart pixel CMOS drive chip.
Enabled by the high modulation bandwidth of the LED devices, the 128x128 pixel
array can project binary patterns at up to 0.5 Mfps and toggle between two
stored frames at MHz rates. The projector has a 5-bit grayscale resolution that
can be updated at rates up to 83 kfps, and can be held in memory as a constant
bias for the binary pattern projection. Finally, the projector can be operated
in a pulsed mode, with individual pixels emitting pulses down to a few
nanoseconds in duration. Again, this mode can be used in conjunction with the
high-speed spatial pattern projection. The design of the smart pixels and LED
devices are presented along with measurements of each mode of operation. As a
demonstration of the data throughput achievable with this system we present an
optical camera communications application, exhibiting data rates of >5 Gbps,
over three orders of magnitude improvement on current demonstrations.
