Flexible screens: Coming soon to mobile, wearable devices
The electronics industry's enthusiasm for curved and flexible displays has the consumer market beckoning, and Kateeva—a Silicon Valley-headquartered company with operations in South Korea—has stepped forward in response, saying that it will start shipping a manufacturing equipment that could finally bring such displays to market, according to MIT Technology Review.
Here and there, manufacturing technologies and prototypes crop up—centred on display screens that are curved, can be bent, folded even. LG Display, for one, revealed last month an 18-inch transparent, flexible OLED panel that can be bent to take the shape of a thin cylinder with a radius of 3cm without botching up the function of the display (see Meet the display of the future: Flexible, transparent OLED).
MIT mentioned that Samsung has released curved phones equipped with flexible displays but ones that are fixed and cannot be bent, saying that this format is easier to seal compared to the other that is bend-capable. Samsung's flexible screen prototype reportedly met trouble with the sealing material used to protect the OLEDs used in the display from water vapour and oxygen.
Flexible OLED or organic LED is the technology behind curved, flexible screens. This device acquires its lightness and bendability by incorporating a flexible plastic substrate, replacing glass used with regular OLED.
OLED manufacturing today is limited by vacuum evaporation techniques that use shadow masks for patterning. It is a straightforward and well-established technique, but inefficient, difficult to scale and prone to yield-killing particles, according to Kateeva.
Enter inkjet printing
Inkjet printing enables deposition of patterned films without the need for shadow masks. EE Times Asia first featured Kateeva's inkjet printing equipment solution here. Dubbed Yieldjet, the solution enables the high-volume production of flexible and large-sized OLEDs. The company said the technology creates an inert environment and better controls particle contamination to boost yield.
Yieldjet is claimed to be the only platform to have a production-worthy nitrogen process chamber. Enclosing printer in nitrogen was particularly challenging because of the need for production worthy serviceability and recovery after maintenance. Kateeva engineers sharply reduced enclosure volume for fast recovery, designed in automated maintenance without air contamination and included a closed-loop nitrogen recirculation system operating at <1ppm O2/H2O.
Kateeva said Yieldjet delivers high film coating uniformity with a process window that is five times wider than standard technologies. This vastly improves process reliability and uptime.
"For more than 15 years, many researchers (including those at Epson) have been engaged in inkjet OLED R&D, and since 2000 there have been various reports on R&D advancements. We believe Kateeva's edge is enabling inkjet to make the transition from R&D to mass production," he added.
This room-sized Yieldjet will pave the way for consumer electronics with bendy display screens.
|Related Articles||Editor's Choice|