Ultrahigh frame rate digital light projector using chip-scale LED-on-CMOS technology
Navid Bani Hassan, Fahimeh Dehkhoda, Enyuan Xie, Johannes Herrnsdorf, Michael J. Strain, Robert Henderson, Martin D. Dawson
Abstract
Digital light projector systems are crucial components in applications, including computational imaging, fluorescence microscopy, and highly parallel data communications. Current technology based on digital micromirror displays are limited to absolute frame rates in the few tens of kiloframes per second and require the use of external light sources and coupling optics. Furthermore, to realize gray-scale pixel values using duty cycle control, frame rates are reduced proportionally to the number of gray levels required. Here we present a self-emissive chip-scale projector system based on micro-LED pixels directly bonded to a smart pixel CMOS drive chip. The <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mn>128</mml:mn> <mml:mo>×</mml:mo> <mml:mn>128</mml:mn> </mml:mrow> </mml:math> pixel array can project binary patterns at up to 0.5 Mfps and toggle between two stored frames at megahertz rates. The projector has a 5-bit gray-scale resolution that can be updated at up to 83 kfps, and can be held in memory as a constant bias for the binary pattern projection. Additionally, 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. As a demonstration of the data throughput achievable with this system, we present an optical camera communications application, exhibiting data rates of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:mo form="prefix">></mml:mo> <mml:mn>5</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>Gb</mml:mi> <mml:mtext>/</mml:mtext> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> </mml:math> .