MicroLED Innovations

Understanding Hybrid Mass Transfer Approach for MicroLED Display Production

Team MicroLED Innovations

·

MicroLED display

MicroLED display, with their potential for superior energy efficiency, color saturation, and brightness, present a promising alternative to existing technologies. 

The global microLED mass transfer market was valued at $45.1 million in 2022 and is projected to reach $1,265.2 million by 2031 at a CAGR of 44.84% during the forecast period 2023–2031.

However, assembling these microscopic inorganic light-emitting diodes (LEDs), known as microLED chiplets, efficiently remains a challenge. 

Recent innovations have led to hybrid mass transfer approaches for efficient microLED chiplet assembly onto display backplanes. These approaches combine techniques like Fluidic Self-Assembly (FSA) and laser-based methods to address the challenges of handling delicate microLEDs at scale.  

This way, hybrid mass transfer aims for high-throughput, cost-effective, and scalable microLED display production while ensuring precision and reliability.

In this blog post, we will explore hybrid mass transfer and discover the role of innovative techniques like FSA and laser-driven methods. 

Exploring the Techniques in Hybrid MicroLED Display Production

Hybrid MicroLED display production is a complex process of transferring microscopic LEDs onto a backplane with driver circuits, offering the potential for high-resolution, high-brightness displays. Let’s dive deeper into each technique:

1. Fluidic Self-Assembly (FSA):

FSA is a technique for making MicroLED displays by shaking tiny LEDs in a liquid until they stick together on a special surface. It demonstrated its utility with 1,500 components two decades ago, but recent advancements have expanded its potential.

  • Challenges: Handling sub-50-µm chiplets poses difficulties due to their delicate nature. These tiny components are delicate, akin to handling fragile glass beads.
  • Solution: With FSA, Researchers increased solution viscosity using poloxamer, enhancing chiplet assembly. Poloxamer not only boosts momentum but also clears microscopic obstacles from binding sites, ensuring better contact between chiplets and solder.
  • Result: A lighting panel was built comprising over 19,000 microLED chiplets emitting blue light.

2. Laser-Based Mass Transfer:

Companies are actively patenting laser-based methods. These techniques ensure precise transfer without damaging microLEDs.

  • Laser Lift-Off (LLO): This method utilizes lasers to remove microLEDs from the sapphire growth precisely substrates they are initially grown on. The laser’s controlled energy allows for a clean and precise separation process, minimizing damage to the delicate microLEDs.
  • Industry Leaders: Recognizing the advantages of laser-based transfer for large-scale production, industry leaders like LG Display, AU Optronics, and eLux are actively exploring and implementing these techniques for manufacturing large-scale microLED arrays.

3. Future Directions:

  • High-Throughput Solutions: Companies like Apple, Samsung, and Sony are actively researching and developing faster and more automated mass transfer methods. This could involve innovations in robotics, conveyor belt systems, and parallel processing techniques to significantly increase production throughput and meet the demands of the market.
  • Materials Innovation: Ongoing research focuses on novel materials to enhance the performance and efficiency of the hybrid mass transfer process. Patents indicate exploration of improved solder materials, offering better thermal conductivity and adhesion properties for secure microLED attachment. 

    Additionally, research on advanced adhesives and protective coatings aims to further optimize the process by improving the reliability, flexibility, and durability of the microLED displays. 
  • Integration with Existing Tech: Recognizing the strengths of existing methods, researchers are exploring hybrid approaches that combine FSA with traditional pick-and-place techniques. 

    This integration leverages the scalability and cost-effectiveness of FSA for bulk transfer while employing the precision of pick-and-place for critical placements requiring higher accuracy.

    This combined approach has the potential to optimize production efficiency and cost while maintaining the desired level of precision for complex microLED display designs.

Patent Landscape in Hybrid MicroLED Display Production

The patent landscape in hybrid microLED display production can significantly impact industry collaborations and partnerships in several ways:

1. eLux:

  • Patent: eLux, founded in 2016, develops fluidic assembly technology to advance manufacturing process developments for microLED displays. It was awarded US patent 9,825,202 titled “Display with Surface Mount Emissive Elements.”
    This patent covers a microLED display based on massively parallel fluidic assembly. This technique is a type of FSA used in the fabrication process of microLED displays.
  • Technology: eLux aims to develop displays that harness the performance of microLEDs while leveraging the existing infrastructure of TFT LCDs.
  • Achievement: eLux claims the ability to assemble microLEDs at an impressive rate of 50 million per hour.
  • Strategic Importance: Their fluidic assembly methods could enable low-cost microLED displays for applications like video walls and, eventually, television.

2. eLux’s Collaborators:

  • In late May 2017, Hon Hai Precision Industry (Foxconn) and Sharp Corporation, in partnership with CyberNet Venture Capital, Innolux, and Advanced Optoelectronic Technology, announced an investment in eLux, Inc.
  • This collaboration underscores the significance of eLux’s research and its potential impact on the microLED industry.

3. LG Display:

  • Patents: Analyzing the patent landscape reveals trends in hybrid microLED display production, where major display manufacturers like LG Display, a leader in laser-based microLED transfer techniques, hold several key patents. 
  • Focus: Their primary focus lies in attaining precise placement of microLEDs during the transfer process while simultaneously maximizing yield. This dual emphasis ensures consistent and reliable display production with minimal waste.
  • Industry Influence: As a major player in display technology, LG’s innovations impact the entire microLED ecosystem.

4. AU Optronics (AUO):

  • Patents: AUO explores patents covering laser-assisted transfer for large-scale microLED arrays.
  • Efficiency and Precision: Their primary focus lies in optimizing production processes using these laser-based techniques, aiming to streamline manufacturing and improve overall efficiency.
  • Market Position: By focusing on efficient and scalable production methods, AUO paves the way for the broader integration of microLED displays in diverse sectors, such as consumer electronics, automotive displays, and potentially even signage and billboards.

5. Other Pioneers and Research Institutions:

Final Note

While microLED displays offer stunning visuals, their production faces challenges due to the slowness of traditional assembly methods and the difficulty of handling delicate microLEDs. Hybrid approaches combining FSA and laser-based techniques provide promising solutions. Whereas FSA enables large-scale parallel assembly, lasers ensure precise placement and minimal damage. 

Research is actively pursuing high-throughput solutions and novel materials and integrating existing methods with FSA to optimize production efficiency. Leading companies like LG Display, AU Optronics, and eLux are actively contributing through patents and implementation, shaping the future of microLEDs. 

Also, it’s not just the big players pushing things forward. Research institutions and startups are also crucial players in developing the technology and shaping the entire microLED ecosystem.