CMOS-Controlled Color-Tunable Smart Display

We demonstrate a color-tunable smart display system based on a micropixelated light-emitting diode (mu LED) array made from one InGaN epitaxial structure with high (0.4) indium mole fraction. When integrated with custom complementary metal-oxide-semiconductor (CMOS) electronics and a CMOS driving board with a field-programmable gate array (FPGA) configuration, this mu LED device is computer controllable via a simple USB interface and is capable of delivering programmable dynamic images with emission colors changeable from red to green by tailoring the current densities applied to the mu LED pixels. The color tunability of this CMOS-controlled device is attributed to the competition between the screening of piezo-electric field and the band filling effect. Comparable brightness of the mu LED pixels emitting at different colors was achieved by adjusting the duty cycle. Further measurement suggests that this microdisplay system can also be used for high-speed visible light communications.