CMOS-Controlled Color-Tunable Smart Display

Abstract

We demonstrate a color-tunable smart display system based on a micropixelated light-emitting diode $(\mu\hbox{LED})$ 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 $\mu\hbox{LED}$ 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 $\mu\hbox{LED}$ 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 $\mu\hbox{LED}$ 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.

Keywords

• Complementary metal–oxide–semiconductor (CMOS)
• InGaN
• $\mu\hbox{LED}$s)%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> microlight-emitting diodes (<formula formulatype="inline"><tex Notation="TeX">$\mu\hbox{LED}$</tex></formula>s)
• color tunability
• microdisplay
• visible light communications (VLC)