Will Mini LEDs Be a Substitute for OLEDs in Smartphones?
October 30, 2017
Taiwan-based LED firms, in view of tight supply of AMOLED smartphone panels and increasing competition in the LED-backlighting segment from China-based makers, are ready adopting mini LEDs for TV and smartphone backlighting applications and fine pixel pitch displays. With sizes of about 100 micrometers, mini LED chip production does not need mass transfer, a technological bottleneck for micro LEDs, the sources said. To cope with tight supply of AMOLED panels, Android smartphone vendors, especially China-based ones, are looking to adopt mini LEDs for backlighting to boost competitiveness against AMOLED-equipped devices, the sources noted. Mini LED backlighting, with local dimming design, can achieve HDR (high dynamic range) and better color rendering index than AMOLEDs, the sources said, adding mini LED panels have the same thickness as AMOLED ones. LCD panel makers AU Optronics (AUO) and Innolux have been working with Android smartphone vendors to develop mini LED backlighting solutions, the sources said. White-light (QDs or Blue with Yellow Phosphor) mini LED chips are used in backlighting, the former able to reach 100% NTSC and the latter 80-90%, the sources noted. According to Epistar, a 5-inch smartphone panel needs 20-25 LED chips or about 9,000 mini LEDs for backlighting. Epistar is ready to produce mini LEDs for smartphone and TV backlighting and fine pixel pitch displays. Lextar Electronics and Advanced Optoelectronic Technology, through cooperation with affiliated AUO and Innolux respectively, are developing mini LED backlighting for TVs, while Harvatek and Opto Tech are developing fine pixel pitch LED displays using mini LEDs.
Taiwan firms developing micro LED are also racing against time to make technological breakthroughs within 500 days, or the technology will be limited to niche-market applications, according to Chen Li-yi, chairman for Mikro Mesa Technology. Successful development of micro LED technology hinges on three elements: the base market, potential market and infrastructure investment. The base market is initial application to generate enough revenues to support development of the technology; the potential market is potential commercial application key to further development of the technology; infrastructure investment refers to establishment of a supply chain for the technology. As micro LED technology is still being developed, it has neither a base market nor investment in infrastructure. However, Chen Li-yi believes the technology will have a wide potential market covering almost all types of display applications. The choice of the base market is key to whether micro LED can become a mainstream display technology and application to large-size TVs, smartphones and VR (virtual reality)/AR (augmented reality) devices could also be a feasible base market for micro LED. Mikro Mesa is developing micro LED panels for 55-inch and above TVs. But such development of large-size applications faces technological difficulties. Micro LED panels under 10-inch involve fewer manufacturing difficulties, feature power savings and high display performance and are suitable for use in smartphones. But such application face strong competition from OLED, given Apple's adoption of OLED panels for iPhone X. Since Samsung Display, LG Display and China-based panel makers have heavily invested in development and production of OLED panels, micro LED panels will find it very hard to compete with OLED in the smartphone field. Small-size micro LED panels can also be used in VR/AR devices, but the value of such devices lies in content and software rather than the display. For 10- to 32-inch display panels, LCD technology dominates the segments and micro LED technology stands little chance of mounting a successful challenge. Therefore, 55-inch and above TV applications would be a market opportunity for micro LED technology. But as large-size LCD TVs are generally inexpensive, micro LED TVs must offer high performance-price ratios to stand a chance of unseating LCD TVs. Based on Mikro Mesa's estimate, a new method of mass transfer can reduce the time taken to produce 55-inch micro LED panels from seven hours originally to 7.5 minutes. In terms of capital expenditure, as production of micro LED panels needs array equipment but not cell equipment, the investment to set up a micro LED panel factory is only 70% and 50% of that for an LCD fab and OLED line, respectively. Mikro Mesa plans to start production of Micro LED panels for large-size TVs in 2018. The mature development of Taiwan's LCD and LED industries gives Taiwan advantages in developing micro LED. OLED panel makers, after establishing a firm foothold in the smartphone market, are making efforts to extend their presence in the large-size TV segment. And if they succeed, room for micro LED's success will shrink sharply. Micro LED faces a critical time and makers involved must accelerate their progress toward commercialization.