Samsung details its flex display
The company’s third generation curved display has a 6.5 radius curvature on each side, a flexibility made possible through the use of polyimide (PI) as a substrate rather than glass traditionally used in AMOLED panels. The display may be more bendable than a human hair at less than a millimeter thick, a release stated.
With the thickness of the AMOLED substrate being less than half the thickness of glass substrates in conventional mobile LCD displays, Samsung has been able to deposit an electronic circuit onto it and evaporate a luminant RGB organic device.
Still, users won’t be able to see the extent of AMOLED’s flexibility because it is encased in plastic. Paul Semenza, an independent consultant, said the major use case he sees for dynamically flexible displays would be in smaller form factors that could roll up to fit in a pocket or purse.
Samsung’s flexible AMOLED display, outside a handset. Source: Samsung.
“If you could ship a device where it was just a piece of plastic that was an OLED, it’s incredible. If you can imagine that for your tablet or smartphone, it almost disappears,” Semenza told EE Times. “That’s what this technology in the real blue sky vision gets to…something light and form-able.”
At this point, plastic substrates are still susceptible to oxygen and water vapor and must be encapsulated by glass or another material. The need to encapsulate the OLED is limiting, despite ongoing research in labs, Semenza said.
OLEDs are still one of the best options for achieving full color and video, as other technologies such as e-ink pose obvious limitations. The AMOLED display on the Galaxy S6 has a 1,440 by 2,560 pixel resolution with a pixel density of 577 ppi, a 75% higher density than that of the Galaxy S5. The new display has more than 3.6 million RGB organic subpixels on its PI substrate, allowing the user to see finer image detail.
Moreover, the flexible display can drive each of its pixels individually to reduce power consumption. The display employs “partial operation technology” that allows a smartphone to make use of 7 mm of each column of the curved display at any one time, reducing power consumption by about 20%.
In a release, Samsung touted the display’s low latency over video. AMOLED has a response speed of 0.01 millisecond.
AMOLED can respond to image transitions quickly because of light-emitting subpixels that produce their own color. On the other hand, an LCD display passes light by changing the orientation of its liquid crystals (LC). So when the LC’s response speed slows – for example at low temperatures, transition time slows down, too. The Flexible AMOLED display…can deliver images up to hundreds of times faster than a mobile device equipped with an LCD (8ms), once new application processors are introduced.
Samsung officials expect demand for curved displays to increase in “the era of big data,” where displaying information on otherwise unused device space will become popular.
“Through the use of bended or flexible display technology, text messages, news and weather information can now be rapidly accessed over a smartphone’s edge screen which previously was wasted,” the release continued.
Semenza was skeptical about the use of “dead” space on phones, which are often quite thin with little unused space. He questioned whether curved displays would be more practical if put on the top of a phone instead of the side.
Regardless of end use case, Semenza said Samsung is leading the pack in development of flexible displays. LG is a close competitor and developing the screen for the Apple Watch, another flexible plastic-based display.
— Jessica Lipsky, Associate Editor, EE Times
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
