RayClouds Photoelectric Technology Co.,Ltd.
RayClouds Photoelectric Technology Co.,Ltd.


In the metaverse virtual space, the host and display industry experts from Germany, Switzerland, the United States, France, the Netherlands and other countries incarnated as the vivid virtual image, and talked about the cutting-edge technology trends and latest research results of the display industry around technical topics such as Mini/Micro LED, AR/VR, and light field display. Recently, as part of the 2022 World Display Industry Congress, a unique display technology seminar was officially launched in the metaverse virtual space, The Overseas Cloud Forum, organized by SID China, was held. The metaverse virtual conference space narrowed the distance between international speakers and the audience, and also makes the online audience feel the charm of the conference mode. The innovative holding of this forum further illustrates the rapid development and integrated application of new-generation information technologies such as 5G, AI, IoT, big data, VR/AR, and promotes the innovation and industrialization of new display technologies. 

Light field display: Improve the immersive experience of VR/AR devices

In recent years, the metaverse has developed rapidly as an integrated innovation and application integrating the Internet, big data, cloud computing, artificial intelligence, blockchain, virtual reality (VR), augmented reality (AR) and other technologies. Technology giants such as Meta, Microsoft, Sony, and Samsung rushed to enter the new track and released related VR/AR terminal products. The rise of the metaverse industry has also promoted the advancement of light field display (holographic) and VR/AR near-eye display technology. 

It is understood that the light field display is to show the light in all directions of the optical scene, including the light emitted at various distances, so it is also called holographic display.

Tomas Sluka, CEO of CREAL, believes that the naked-eye 3D display vision realized by light field display is expected to become the next generation of display technology. According to Sluka, the difficulty in implementing this technology is that the distance depth is achieved only through the naked eye. CREAL's solution is to project a series of narrow-aperture images through an array of viewpoints in the pupil. Each of these array viewpoints can provide an always-focused image, and all of these viewpoints together can present a 3D scene in front of the observer on the retina. This is sufficient to provide depth of focus for all uses, even visual parallax. According to Sluka, the light field display system developed by the CREAL team offers a very good tradeoff between resolution and the number of viewpoints. At present, the light field technology developed by the company has also been applied in VR headsets. CREAL released a forehead display with a light field of 30°FOV angle and peripheral images with an angle that more than 100°FOV, which can help users get better visual images. 

Currently, most VRAR headsets on the market only support convergence and dispersion, but do not support adjustment, which means that the image is fixed at a fixed focus depth. If the VR/AR device is equipped with a light field display, the user's eyes can focus at any depth in the VR/AR headset scene, just like looking at the real world. Based on this, optical field display has become a new technical competition point for enterprises. 

Internationally,CREAL launched prototypes of AR and VR headsets based on the company's optical field displays in January this year, optimizing virtual display scenarios. Domestically, in September this year, TCL CSOT announced that it had produced the world's first 32-inch 8K floating touch light field display and the world's first 32-inch 8K large viewing angle multi-view light field display. It is understood that TCL CSOT light field display provides the brain with "monocular stereoscopic vision" information by realizing "continuous motion parallax", "monocular stereoscopic image adjustment" and other functions, which can simulate the real visual effect of the human eye, and can alleviate the "motion sickness" problem. 

Micro LED: Key technologies in all links are accelerating industrialization

Micro LED is considered to be the third generation of new display technology, compared with the previous traditional first generation LCD and second generation OLED display, it has high resolution, high luminance, high contrast, high color saturation, low power consumption, fast response, thin thickness, long life and many other advantages, is one of the most potential new display technology. 

Ioannis John Kymissis, dean of Columbia University's School of Electronic Engineering, introduced the physical properties of Micro LEDs to attendees. He says LED have very high peak brightness, excellent color recovery, and very high luminous efficiency, so they are commonly used in consumer electronics display screens and billboards. It is worth mentioning that LED is the most efficient and controllable light source made by humans, and its luminous efficiency is very close to the thermodynamic limit. The luminous efficiency of commercial display devices can even exceed 50%, which means that for every 1 watt input to an LED product, it converts that 1 watt into more than 50% of light. In addition, the lifetime of the LED can exceed 50,000 hours, and the luminance can reach tens of millions of nits...... It can be said that LED is a very worthwhile research field of display technology.

The industrialization process of Micro LED requires the cooperation of enterprises, universities and research institutes in all links of the industrial chain to break through the key process technologies, and promote product applications to achieve rapid development of the industry. At present, related companies are increasing the layout of the whole industry chain of Micro LED, and manufacturers such as chips, packaging, panels, terminals, and glass are advancing to Micro LED. 

Rajesh Vaddi, a senior scientist in Corning's R&D department, first affirmed the broad application scenarios of Micro LED display in the future. Corning's glass-based product portfolio can meet the needs of LCD technology and emerging technologies such as Micro LED and Mini LED, he said. As an upstream enterprise of the industry chain, Corning's glass-based product portfolio can solve some of the complex challenges of Micro LED display integration. For example, Corning can achieve active matrix splicing or zero-border display through the integration of metallized through-holes and TFTs, and also realize the potential application of Micro LED and other display electronic backplanes. 

Micro LED is still in the early stage of development, and how to industrialize it is a problem in front of the global Micro LED industry. “To do one thing well, preparation is very important.” In the display field, the production equipment determines the product quality, performance, yield, and is directly depend on the cost. In terms of production equipment and testing methods, the participants also shared the latest progress and achievements of their team.

John Robinson, senior chief scientist of KLA, pointed out that Micro LED's small size can be easily placed into sensors, cameras, antennas and other types of devices, and the application scenarios are very broad, but its cost and manufacturing capacity are key challenges in the commercialization process of Micro LED. Robinson introduced the possibility of mass production improvements in epitaxial and Micro LED yields, backplane yields, and massive transfer and bonding rate. For all three of these ways to improve the efficiency of Micro LED mass production, KLA can provide detection optimization solutions. For example, when it comes to improving backplane yield, KLA has the Flare bp inspection tool for Micro LED backplanes, which has multimodal imaging technology that can quickly switch between light sources with different wavelengths or angles to improve defect detection and classification. In terms of massive transfer and bonding rate, the luminance, color uniformity and the defect management of redundancy and repair are all critical to successful production because the high precision LED placement machine requires mechanical and electrical bonding. KLA can provide Flare MT detection and measurement tools for the production of Micro LED massive transfer, which can provide more accurate prediction of successful bonding and provide immediate feedback for massive transfer. 

The improvement of production yield will accelerate the industrialization process of Micro LED. It is estimated in the industry that Micro LED is expected to be commercialized on a large scale in 2024, and China is expected to reach a market scale of 80 billion yuan. With the continuous advancement and improvement of Micro LED production technology and production equipment, the threshold for new companies to enter related industries will also be significantly reduced. 

Eric H. Virey, general manager of display business of Yole Intelligence, introduced the current state of Micro LED massive transfer process and production equipment. He pointed out that although the development of the Micro LED industry has slowed down in recent years, it has now entered a more virtuous cycle. Eric also said that the massive transfer problem that currently perplex the mass production of Micro LED has not been completely solved. However, the emergence of yield improvement technologies and equipment as well as process improvements methods over the past few years have improved the yield of massive transfer, making this process no longer a significant barrier to mass production of Micro LED. The existing technology and production equipment significantly reduce the technical threshold for display companies to enter the Micro LED market, and objectively it will also accelerate the industrialization of Micro LED. 

RayClouds is a high-tech enterprise focusing on optical measurement. We took the market as the guide, took scientific research as the core, and took innovation as the impetus to developed the SR-Series Spectroradiometer, which is effectively applied to the luminance and chrominance analysis of OLED, Micro/Mini LED and other luminous panels. Improving the yield of products from the aspect of imaging, and help accelerate the industrialization process of Micro LED. 

Source: 中国电子报  Official Accounts
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