The Korean research team has developed the world’s first next-generation display technology that can simplify the process and significantly reduce incidental expenses. The new materials required for the new process were also developed for the first time in the world and are expected to significantly help the Korean industry to maintain its leadership in the next-generation display market.
The Electronics and Telecommunications Research Institute (ETRI) announced that new materials suitable for the new technique have been developed to solve the challenges of micro LED1) display technique.
The Micro LED display is a new generation self-emitting display using a micro LED2)as a pixel light source. The research team made 12 micro LEDs in 1mm2, and more vivid colors can be realized compared to the LCD screen3) or OLED4) display. It also has such high luminous efficiency that it can be used in various fields such as TV and smart watch etc.
In particular, the micro LED display controls the RGB elements separately for the precise expression of screen brightness and color, and the inorganic semiconductor can be used for a long time without worrying about the burn-in phenomenon deterioration in quality.
To develop the product, the micro LED produced by the semiconductor process must be transferred to the display panel. For 8K TV, about 100 million micro LEDs are needed, and the size is also very small, which requires a long time to transfer and link. The materials needed to make the display stand also depend on the import, so the price is very high5).
All existing methods were based on sequential processes: the âtransfer processâ then the âbinding processâ. ETRI’s research team developed the new materials, SITRAB6) adhesives, intended to be used to combine the transfer and bonding processes into a single process.
The research team applied a homogenized laser to the SITRAB film attached to the micro LED for a few seconds to develop the central process of simultaneous transfer and bonding7) to overcome the challenge.
The key to this developed process is to apply the homogenized laser over a large area but only heat the part to be fixed to mount the micro LED on a display panel substrate; this technique made it possible to avoid the inconvenience of carrying out the transfer and bonding processes separately. The new materials suitable for the relevant technique have also been independently developed to provide the possibility of using the material not only for micro LED, but also on new generation display technology such as mini LED etc.
By applying the technology developed by ETRI, the high investment costs that were previously required for transfer and bonding equipment can be reduced and the process can be simplified to increase manufacturing capacity. In addition, newly developed materials can be fixed with additional micro LEDs even when laser applied multiple times for greater convenience in repairing defective pixels.8). Therefore, the limitation of the existing process, that is, the inability to perform repair, can be solved.
The micro LED, presented for the first time by the research team, was developed with a blue color among the RGB, and the prototype with 1225 micro LEDs out of 100mm2 has been demonstrated.
In particular, the transfer and bonding material which was mainly imported from Japan could be secured to create a new market through the development of new materials without the need for local manufacture. The developed technology can also be used with locally developed equipment instead of expensive foreign equipment, making it favorable for commercialization.
By applying this technology developed by ETRI to the real industrial field, the investment cost in equipment and the processing time can be reduced to 1/10 compared to the existing technique, and the costs and time of material and repair can also be reduced. be reduced to 1/100 or less.
The research team attributed this result to the relevant equipment and process development efforts based on the know-how sought on new differentiated materials technology for 16 years by ETRI. ETRI expects relevant products such as smart watch and TV etc. be commercialized within 2 years by transferring the technology to Korean display companies, etc.
âIn the field of R&D where global display companies compete, ETRI has become the first institution to overcome the limitations of existing display. ETRI will continue its efforts to enable Korea to become the leader in new generation display and maintain its status of the country with advanced technology, âsaid Dr. Choi, Kwang-Seong, team leader of multifunctional materials for micro LEDs at ETRI and the Ministry of Science and Technology.
According to the 2020 report by market research firm Omdia, the micro LED market is expected to register an average annual growth rate of 65% until 2027 for the scale of the relevant market to reach $ 71 billion. The supply of LED smartwatches is also expected to exceed 10 million, with micro LED TVs also exceeding 3.3 million.
Using this simultaneous transfer bonding technology and laser new material application process technology, ETRI has filed and registered 32 patents and presented 5 relevant theses.
About the Electronics and Telecommunications Research Institute (ETRI)
ETRI is a government funded, not-for-profit research institute. Since its founding in 1976, ETRI, a global ICT research institute, has made immense efforts to provide Korea with remarkable growth in the field of ICT industry. ETRI makes Korea one of the world’s leading ICT nations, continuously developing the world’s first and best technologies.
This research was carried out with the support of the Material Innovation Leading Project of the Ministry of Science and ICT (MSIT), with the participation of the Korea Institute of Science & Technology, the Korea Institute of Engineering and Technology of the ceramics and the Korea Institute of Industrial Technology. as joint research institutes.
The research team announced the technology through the Latest-News Paper * at SID Display Week 2021, the world’s largest display symposium; thus making it possible to recognize the excellence of the technology.
* Thesis title: Simultaneous Transfer and Gluing Processes (SITRAB) for a mini-LED display
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1) Measuring 1/10 of the mini LED, the display uses micro LEDs measuring about 10 ~ 100Î¼m
2) Light Emitting Diode (LED). Semiconductor device emitting light when applied with forward current
3) Liquid crystal display. The phenomenon of filtering light when voltage is applied in the LCD display, which has both solid and liquid properties, is used.
4) Organic light emitting diode. The film of organic compound emitting light by reacting to voltage is used.
5) 110-inch TV recently launched in March by the Korean electronics company: around KRW 170 million
6) SITRAB (Simultaneous transfer and bond)
7) LAB (Laser-Assisted Bonding) process: bonding process of applying a homogenized laser to the chip or semiconductor package for bonding
8) Repair or recovery of the defective pixel after transfer and gluing (detach the existing LED to fix the new LED)
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