Micro-LED, also known as mLED or μLED, is an array composed of micron-scale semiconductor light-emitting units. These devices convert electrical energy into light energy and are transferred in bulk to a drive circuit substrate, which can be either rigid or flexible, through mass transfer technology. Subsequently, a protective layer and external electrodes are prepared on it through methods such as physical vapor deposition, followed by encapsulation. LED materials are typically made of III-V compound semiconductors, such as gallium arsenide (GaAs) and gallium nitride (GaN), which are known for their excellent optoelectronic properties. The core structure of an LED is a p-n junction formed by p-type and n-type semiconductor materials. When a forward voltage is applied, electrons and holes from the n-type and p-type semiconductors inject into the depletion region and recombine to emit light.
Micro-LED display technology miniaturizes and matrices these light-emitting diodes, with individual light-emitting units smaller than 50 μm, densely integrated on a chip. It features two main characteristics: first, a high pixel density 2D Micro-LED array, and second, each pixel can be addressable and independently driven for emission.
Micro-LED combines new display technology with traditional LED technology, offering advantages such as self-emission, high efficiency, low power consumption, high integration, stability, and the ability to operate under all conditions. It is regarded as one of the most promising next-generation display and lighting devices. Due to its small size, high flexibility, and ease of disassembly and integration, Micro-LED can be deployed in any display application, from the smallest to the largest, and in many cases, it outperforms LCD and OLED displays.
In recent years, with acquisitions such as Apple’s purchase of Luxvue, Facebook’s acquisition of Oculus, Sharp’s acquisition of eLux, and Google’s investment in Glo, Micro-LED technology has garnered widespread attention. These major brands are interested in Micro-LED for its ability to deliver high contrast, high-speed displays with wide viewing angles, along with broader color gamuts, higher brightness, lower power consumption, longer lifespan, greater durability, and better environmental stability.
Micro-LED displays outperform OLEDs in performance and can integrate sensors and circuits, achieving thin displays with embedded sensing functions. However, Micro-LED technology still faces challenges, such as the maturity of mass transfer technology, high manufacturing costs, and low pixel efficiency. Currently, the peak efficiency of Micro-LED displays is generally below 10%, and efficiency drops even further when operating at low current densities.
In terms of applications, Micro-LED display technology is suitable for various display applications, from the smallest to the largest. It holds particular promise in areas such as smartwatches and AR/VR head-mounted displays. Smartwatches, with fewer pixels and moderate pixel density, make chip and assembly costs efficient, aligning well with the current state of Micro-LED technology development. AR/VR headsets require high brightness to compete with ambient light, where Micro-LED offers a significant advantage.
Despite challenges in the smartphone and television markets, Micro-LED’s application potential in these fields remains substantial. As technology advances and the industrialization process progresses, Micro-LED is expected to become the mainstream direction for next-generation display technology.
