TAIPEI -- The most expensive handsets in the upcoming iPhone 10th anniversary range will feature advanced organic light-emitting diode screens that have curved edges, to be solely provided by Samsung Electronics, a source familiar with the design said.

The curve will be gentler than screens in Samsung's Galaxy S7 Edge handsets. This is partly due to the challenges of making curved glass covers to match screens, according to the source.

While the curved screen will allow a viewable area of about 5.2 inches and make the iPhone even sleeker, it will not offer significant new functions, the person said.

Curved OLED screens on smartphones are pioneered by Samsung, and Chinese companies including Vivo and Huawei have also released high-end handsets with the feature. Smartphone makers have pounced on the new display as they seek to differentiate their designs from a plethora of Android phones available in the saturated global market.

Compared with current mainstream liquid crystal display technology adopted by most smartphones, OLED panels offer sharper color contrast. But Apple is a latecomer to the scene, and like the others, are not thought to be able to offer any game-changing functions with the curved screens.

Some reports suggest in recent days that Apple will only give the premium handset a flat display, but the source said that would not be using OLED optimally. Nonetheless, the design has not been finalized and could still change.

China's Biel Crystal and Lens Technology will supply the glass backs for the new handsets and, together with key iPhone assembler Hon Hai Precision Industry, will provide the front glass covers, the person said.

Together with the OLED iPhone, Apple is expected to release two other lower-priced handsets with flat screens that measure 4.7 inches and 5.5 inches, as part of its 10th anniversary range later this year.

Apple declined to comment.