Key Considerations for Characterizing Mini-and Micro-LEDs

The energy efficiency, longevity, and versatility of light-emitting diodes (LEDs) have made them popular in various applications, including lighting sources in homes, offices, automotive, and electronic displays, as shown in Figure 1. LED technology continues to advance to meet evolving demands.

This progress involves integrating advanced features, such as smart lighting with internet of things (IoT) technology, and enhancing efficiency in LED lighting or indicators by improving luminous efficacy, heat management, and overall performance. Moreover, ongoing developments in display technology aim to enhance contrast ratios, energy efficiency, and resolution in LED displays, such as mini- and micro-LEDs, which comprise thousands of LEDs.

Micro-LEDs offer significant advantages over organic light-emitting diode (OLED) and liquidcrystal display (LCD) technologies, such as higher brightness, better efficiency, and the ability to integrate additional functionalities like sensors. However, their high production costs and technical complexities have limited their use primarily to niche markets such as augmented reality (AR) / virtual reality (VR) displays, automotive lighting, and transparent displays. These improvements drive a growing demand for measurement systems to evaluate LED characteristics.

Key Electrical Characteristics of LEDs

When developing or manufacturing LEDs, it is crucial to understand their electrical, optical, and light-current-voltage (LIV) characteristics to ensure optimal performance and functionality. Understanding the electrical properties ensures that the LED operates within specified voltage and current ranges, which is critical for circuit design. Conversely, optical characteristics offer insights into emitted light quality, including brightness, color accuracy, and distribution. LIV characteristics provide valuable insights into the relationship between light output, current flow, and voltage, enabling optimization of operation parameters for energy efficiency. Table 1 outlines the electrical characteristics of LEDs; Figure 2 illustrates the IV and thermal characteristics.

LED Characterization Using a Source / Measure Unit