Rollable OLEDs are nothing new. LG has been showing its OLED-R horizontally rollable TV display on the trade show circuit for years, and BOE has shown a rollable prototype. But in late October, TCL’s China Star Optoelectronics Technology showed OLEDs at the on-line DTC 2020 that were both rollable and ink-jet printed.
The primary demo was a 17-inch, sideways rollable panel (Fig. 1). A sideways rollable display may be less practical than a horizontally rollable one. But this isn’t a product, it’s way of demonstrating the capabilities of CSOT’s panel. The company says that it has reduced the panel’s thickness and increased its flexibility by removing the color filters used in earlier versions.
Fig. 1. TCL CSOT showed this 17-inch ink-jet-printed sideways rollable OLED display at DTC 2020. The demonstrator is shown in its rolled (left) and unrolled (right) states. (Photo: Source unknown)
Question: Why use a color filter with an emissive display already having red, green, and blue (RGB) sub-pixels? The typical reason is because the RGB emission spectra overlap, and the filter is used to suppress the overlapping regions, thereby improving color purity. Is TCL sacrificing color purity for the sake of flexibility, or has it improved its IJP OLED materials so that the filter is no longer needed? Or is it a mixture both?
That brings us to some difficulties that ink-jettable materials have. Despite improvements, ink-jettable materials have lower efficiency and poorer lifetime than the evaporated materials used by LG and Samsung in their current products. Since efficiency and lifetime are already issues for OLED displays, I have to wonder whether consumers will accept the compromises likely to be present in the first wave of high-volume, flexible, IJP display products.
Okay. So when are these displays likely to be manufactured in volume?
TCL has announced it will spend US $6.8 billion on its new T8 Gen 8.5 IJP OLED fab, which will be built in Guangzhou from 2021 to 2023. In mid-October at the 2020 China International OLED Industry Conference, Zhao Bin (General Manager of TCL Huaxing R&D) said that initial volume production is scheduled for 2024, reported the Chinese-based Times Weekly. “It’s progressing smoothly,” said Zhao. The Guangzhou T8 production line project is under preparation.” (KW)
Ken Werner is Principal of Nutmeg Consultants, specializing in the display industry, manufacturing, technology, and applications, including mobile devices, automotive, and television. He consults for attorneys, investment analysts, and companies re-positioning themselves within the display industry or using displays in their products. He is the 2017 recipient of the Society for Information Display’s Lewis and Beatrice Winner Award. You can reach him at [email protected] or www.nutmegconsultants.com.
