CMOS-Controlled Color-Tunable Smart Display

Abstract

We demonstrate a color-tunable smart display system based on a micropixelated light-emitting diode ðLEDÞ array made from one InGaN epitaxial structure with high (0.4) indium mole fraction. When integrated with custom complementary metal-oxidesemiconductor (CMOS) electronics and a CMOS driving board with a field-programmable gate array (FPGA) configuration, this 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 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 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.

Active-Matrix GaN Micro Light-Emitting Diode Display With Unprecedented Brightness

“…Array A is similar to previously reported microdisplays [3], [18] and serves as a reference. It consists of 85 × 85 μm 2 mesas at 100-μm pitch, forming a 10 × 10 array.…”

“…LED operating voltages up to 8.3 V are possible by supplying a CMOS compatible voltage of 3.3 V (with respect to GND) on the LED_VDD terminal and −5 V on the LED_GND terminal. Note that the CMOS driver reported here is the latest development in a series of driver chips specifically designed for driving micro-LED pixel arrays [1], [10], [16]- [18]. In this section, we compare the present driver (generation 2) to the previous one (generation 1) [10], [18].…”

9.2: Invited Paper: Applications and challenges of Micro‐pixelated light‐emitting diode arrays

“…Another way is that when integrated with custom complementary metaloxide-semiconductor (CMOS) electronics and a CMOS driving board with a field-programmable gate array (FPGA) configuration, this micro-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 micro-LED pixels. [10] 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 micro -LED pixels emitting at different colors was achieved by adjusting the duty cycle, shown in Fig.…”

1.5 Gbit/s Multi-Channel Visible Light Communications Using CMOS-Controlled GaN-Based LEDs

“…Fig.1 (d) shows the layout of the CMOS driving board and corresponding data input ports. More details about the design and function of the CMOS electronics can be found in our previous publications [11] [18].…”