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Evolution of ultra-large mini-LED technology


With the increasing demand for large size, the oversized mini technology has also been pursued by major enterprises! The founder of Mini Optoelectronics, who delivered a speech on the theme of "evolution of oversized mini technology" at the 2020miniled industrial technology summit, mentioned that there are two applications of mini technology in the future: one is the application of oversized display, and the other is the application of small-sized ultra-micro high-precision display.

Miniled will develop towards large size in the future. Compared with the previous ones, the resolution of large size will be higher and higher. At present, it can achieve 1mm and 0mm. At present, Mini Optoelectronics has introduced 0.6mm LED display. At present, 80% - 90% of the technology of mini LED is focused on small size mini LED applications, with strong endurance, which is a great advantage for consumer electronics.

The LCD back uses Mini LED technology as backlight. This backlight can dynamically partition and improve contrast and color gamut. Miniled can be used as commercial display, including conference rooms and various commercial displays. The future conference room also needs human-computer interaction, which is the future trend. Now it is defined that more than 100 inches is super size, and the To C end is the home theater system. The home theater system will gradually become practical.

At present, most of the home theaters use projection or LED with more than 100 inches. It is difficult to enter the house with more than 100 inches. The disadvantage of projection is that brightness, color and accuracy are not up to standard from the perspective of high image. In the future, the trillion-level market of super-sized mini applications will be released in the home theater system. In the future, the command and monitoring market will be 10 billion, the commercial display market will be 100 billion, and the home theater market will be a trillion market.

He also mentioned that in the display based on miniled, each pixel must be composed of three chips, red, green and blue, which are realized by driving. For example, the 110-inch area is 3 square meters, and the future standard home theater will have a resolution of only 1.2 mm, and a 4K resolution of only 0.6 mm. If the 8K resolution is 0.3 mm, then we are entering the 5G+8K era.

In the future, if the market is to expand, the mini size must be ultra-high definition, and it must also be the lowest cost. The cost of pixels is very important. The mini size has been industrialized, and used in the display wall of the command center. This price can be accepted by the market. If you enter the middle and high-end conference room, you need to reduce the cost.

The chips used by miniled currently include the front chip and the flip LED, and there are also vertical chips at present. The so-called "mini" is based on COB technology. Assume that the current minimum spacing is 0.8mm when using a formal chip; As for the mixed loading method, the spacing can be 0.7 mm. If it is inverted, it can reach 0.3 mm micron. two × The flip chip of 4mil brings many problems to be solved; The latest vertical chip requires a line at the front and back of the vertical blue-green chip, saving the minimum spacing between pixels to 0.6 mm. Assume that the pixels of the mini LED of consumer electronics are very high, and the existing chips, including the substrate and drive technology, will change. Based on the 100-inch 4K application, 0.6 mm can basically meet the requirements. If it is used for VR/AR glasses, new substrate technology, new driver technology and new chip size must be used to meet the requirements. At present, the biggest advantage of consumer class is its endurance, including higher ppi. Now the mobile phone 300-500ppi and the future 3000-5000 ppi must have smaller LED chips, updated substrate technology and driver technology.

At present, Mini is at the forefront in this field. Both the formal and flip technology have chips, which are used in 4 × 6、4 × 8 level. In the next few years, the super-large is the miniled product with more than 100 inches, which is the way of coexistence of several types of chips, but ultimately depends on the product's cost performance.

Ultra-large miniature technology, including substrate technology, glass substrate technology and drive technology. Substrate technology is mainly used in PCB substrate, and glass substrate can be less than 0.5 mm in the future. Glass substrate technology. At present, the glass substrate technology is not only consumer-grade, but also more than 100 inches. Now Mini is studying how to solve the splicing problem of glass substrate, and the technical problem of multi-layer plates on glass substrate. Splicing is a relatively important problem. Drive technology includes active TFT-based drive technology. Only this technology can significantly reduce the drive cost of miniled in the future. At present, the top four materials of mini P0.6 and P0.9 mini products include driving costs. Drive cost, substrate cost and chip cost are the top three aspects. In the future, Mini will be used more widely, which is the direction.

Chip transfer is also an important aspect of the massive transfer technology of miniled. Above P0.6, the current technology of using single chip and multiple chips is suitable, because the chip size is not so small. If the chip size is very small, there is no way to use mechanical methods, which must be solved by other methods. Therefore, the speed, accuracy and cost of the transfer are the main indicators of whether it can be applied on a large scale in the future.

Finally, he also shared the pixel engine technology released by Mini in the world for the first time last month. The pixel engine technology is that Mini Optoelectronics applies the pixel common-phase technology previously applied in OLED field to mini through hardware and software. Hardware effectively multiplies pixels by adding colors, using physical layout and software algorithms. Samsung has already used this technology on Apple's Oled screen. At present, the mini pixel engine technology has launched projects of P0.63 and P0.79. The color performance of the project is very good, the contrast is higher, and the resolution is greatly improved. Miniature covers both packaging and display, combining the packaging of midstream and downstream display applications. It is hoped that 0.4 mm will be launched in the first quarter of 2021 and 0.3 mm by the end of next year.

At present, miniled is the first to realize the application in the field of more than 100 inches. This application has been basically realized through the encouragement of OLED industry chain. In the future, there are still many problems to be overcome, including upstream chip technology, substrate technology, drive technology, transfer technology, online maintenance technology, future updated and unknown technology, which is the direction of Mini's future efforts!