Introduction

With each pixel acting as its light source, MicroLED displays offer high contrast ratios, brightness levels, and color accuracy. But, what truly sets MicroLED apart from other display technologies is its color tunability at the pixel level.

With a color tunable pixel microLED display, any color in the spectrum can be produced. This eliminates the need for separate red, green, and blue subpixels commonly used in traditional displays. This enhances the display’s color accuracy and vibrancy, including increasing the pixel density.

From a commercial standpoint, color tunable pixel technology opens up new opportunities for product differentiation and market segmentation.

The size of the micro LED market is anticipated to reach USD 1.48 billion by 2029. It is expanding at a compound annual growth rate (CAGR) of 81.80% between 2024 and 2029.

This article explores the fundamental ideas behind MicroLED display and its importance in the industry.

Innovations in Color Tunable Pixel Technology for MicroLED Displays

Color tunable LEDs combine LEDs of different color temperatures into a single unit. By controlling the intensity of individual LEDs inside the unit, you can shift or “tune” the color temperature within the fixture. This technology is a game-changer for many industries and business environments.

Moreover, the evolution of display technology has brought about significant advancements in pixel design. Traditionally, each pixel on a display comprised distinct red, green, and blue subpixels. In a subpixel-less design, each pixel is thought to be a single LED that can produce any color. 

Therefore, it eliminates the requirement for distinct red, green, and blue subpixels and considerably increases the pixel density, producing crisper and more detailed images.

Let us explore some of the key innovations in this field: 

1. Q-Pixel’s Innovations 

Q-Pixel, a startup based in Los Angeles, has developed proprietary polychromatic microLEDs and microLED displays. Their technology allows for full-color tunability across a single 4-micron pixel, replacing the conventional tuning by combining single-color LEDs. 

This has enabled Q-Pixel to achieve several world records, which includes the creation of the world’s smallest full-color pixel (at a 1-µm size). This also creates the highest-resolution active-matrix color display with a resolution of 6800 pixels per inch.

2. Porotech’s DynamicPixelTuning® Technology 

Porotech, a pioneer in micro-LED and GaN-based semiconductor material technology, has developed DynamicPixelTuning® technology. This breakthrough makes it possible to create full-color or tunable-color monochrome displays using identical pixels from a single wafer. 

The technology is set to accelerate the commercialization of micro-LEDs, mini-LEDs, and LEDs. This is to deliver next-generation display products for AR/MR/VR applications, smart wearable devices, smart displays, and large-scale direct-viewed displays.

3. Applied Materials

Applied Materials has used innovative quantum dot (QD) technology to present a novel process for full-color MicroLED displays. 

The research, led by Mingwei Zhu and his team at Applied Materials, draws comparisons between various architectures and manufacturing methods. This method uses UV MicroLEDs with red, green, and blue (RGB) QDs, offering several advantages over traditional approaches.

Patents on Color Tunable Pixel Technology for MicroLED Displays

These patents highlight the ongoing innovation in the field of color tunable pixel technology:

1. Dynamically Tunable, Single Pixel Full-Color Plasmonic Display

This patent (US10175547B2) describes a dynamically tunable, single pixel full-color plasmonic display. The technology enables color-changing surfaces that have many applications, including but not limited to displays, wearables, and active camouflage. 

The invention contemplates a novel liquid crystal (LC)-based apparatus and methods. It enables tuning and demonstrates a liquid crystal-plasmonic system that covers the full red/green/blue (RGB) color basis set as a function only of voltage.

2. A Modular Design of Continuously Tunable Full Color

This proposes a plasmonic pixel whose color can be continuously tuned over the entire hue range. This is done by adopting the modular design approach in which independently tailored plasmonic nanoantennas serve as color modules. These are combined into a composite unit cell.

3. Plasmon-Based Color Tunable Devices

This patent (US20090034055A1), titled “Plasmon-based color tunable devices,” discusses plasmon-based color tunable devices. This allows controlling the intensity, color, phase, polarization, or direction of light arriving from an independent light source. 

These plasmons are quasiparticles resulting from the quantization. The quantization of the oscillations of the free electron gas density occurs at the interface between a conductor and an insulator.

Current Market Trends in Color Tunable Pixel Technology for MicroLED Displays

Here are some of the current market trends in color tunable pixel technology for MicroLED displays:

Growing Market Size

The global market for MicroLED displays is expected to grow significantly in the coming years. 

According to ResearchAndMarkets.com, the global market for MicroLED displays is projected to grow from 2024 to 2034. The numerous advantages of MicroLED technology, including high brightness, long lifespan, and energy efficiency, drive this growth.

Investment in Research and Development

Significant investment has been made in the research and development of MicroLED technology. As of 2023, $11.5 billion has been spent on MicroLED development. Startup funding is also expected to reach a record high in 2023, exceeding $400 million.

Advancements in Manufacturing Processes

Companies are continuously innovating and improving the manufacturing processes for MicroLED displays. 

For instance, 

• Applied Materials has introduced a new method for creating full-color MicroLED displays using innovative quantum dot (QD) technology. 
• Porotech’s DynamicPixelTuningⓇ and its ability to create full-color or tunable-color monochrome displays using identical pixels from a single wafer also deserve mention.

Commercialization Efforts

Several companies are making efforts to commercialize MicroLED technology. For example, 

• Apple plans to invest more than $2 billion in establishing a smartwatch display production. This smartwatch has an 8″ MicroLED chip fab at ams OSRAM. 
• Samsung is planning to increase the manufacturing of microLED TVs in 2023.

Challenges in Color Tunable Pixel Technology for MicroLED Displays

These are the challenges and future directions in the field of color tunable pixel technology for MicroLED displays:

1. Mass Transfer Process: One of the major challenges in the mass production of MicroLED displays is the mass transfer process. 

This involves transferring millions of MicroLED chips onto circuitry, a process known as micro-assembly. The current pick-and-place approach needs to be faster and cheaper for commercialization. Alternative techniques like stamping show promise but still need help with scale-up and non-uniformity issues.

2. Color Conversion: Developers are working to address challenges such as color conversion. Techniques like quantum dot color conversion help compensate but introduce complexity.
3. Efficiency Drop: At sizes below 10 microns, MicroLED efficiency drops drastically due to surface recombination and plasma etching damage. New solutions like ALD passivation have improved efficiency to a degree, but red and UV MicroLEDs still need to catch up to blue and green.

End Note

The future of display technology, particularly MicroLED, holds exciting prospects driven by ongoing advancements. Pixel driving technology is evolving to enhance brightness uniformity, speed, grayscale, and frame rate, optimizing MicroLED performance across various applications. DynamicPixelTuning®, enabled by innovations like porous gallium nitride, promises versatile displays capable of emitting a wide range of wavelengths. 

However, several challenges remain, particularly in monolithic integration, due to material limitations, such as the inability to achieve pure red emission. Yet, with ongoing research and the exploration of novel nanostructures like nanowires, these hurdles can be overcome, paving the way for even more remarkable MicroLED display innovations.