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What’s Going on Inside Curved Phones?

Right after Samsung’s commercial launch of Galaxy Round, a smartphone that is curved along the horizontal axis, LG launched G Flex, which is curved along the vertical axis. It seems like the manufacturers had different use cases in mind. The Galaxy Round’s slight curvature makes it easier to grip and fit better in one’s hand, especially for people with smaller palms, and in front pockets. The G Flex, on the other hand, fits better in back pockets and touts a better viewing experience when watching video horizontally.

In terms of hardware specifications, both devices are very similar; both adopt Qualcomm’s Snapdragon 800 and offer 13 Mpx cameras. The G Flex is larger and heavier than the Galaxy Round, though it does have a significantly larger battery capacity of 3500 mAh, compared to the Galaxy Round’s 2800 mAh. The G Flex uses a curved battery produced by LG Chem.

Of course, the striking thing about both of these smartphones is the break from the flat slab form factor, which requires the display to be curved. Both smartphones use curved AMOLED displays, Galaxy Round with a 5.7” full HD (1920×1080) display and G Flex with a 6” HD (1280 x 720). Both displays are produced on plastic substrates that are laminated to carrier glass during production and then lifted off the glass. The AMOLED in the G Flex is produced by LG Display, while the Galaxy Round AMOLED is made by Samsung Display with significantly higher resolution (386 PPI as opposed to 245 PPI in the G Flex), an indication of Samsung Display’s more mature evaporation technology.

Samsung dominates AMOLED display production and smartphones using AMOLED. LG Display has focused more on using AMOLED for large TVs, including introducing the first curved TV using AMOLED earlier this year, not long after producing the first OLED TV, while focusing on LTPS and IPS LCD technologies for smartphones. In fact, according to our OLED tracking, LG Display’s production if AMOLED smartphone displays (on glass) has been declining for several quarters, while it developed production of AMOLED on plastic. Outside of Korea, AUO and Japan Display have been developing AMOLED displays for mobile applications, but are not shipping in volume.

While Samsung and LG have demonstrated the capability to produce curved displays, the next step – truly flexible displays – may be some time off. For glass-based displays, the ability to actively bend the display may require some sort of lamination to plastic; for plastic-based displays, the challenge has been creating a thin-film encapsulation that reliably protects the organic materials.

Thin devices in a curved shape also present a challenge for other components, including the PCB and battery (LG indicated that it developed a new configuration that reduces stress, improving stability and performance). Due to the physical curvature, there are limitations on the ability to position components in the case. The limitation is pushing device manufacturers to seek alternative materials for PCB board and battery casing, which will keep costs high until mass production is reached.

  • Anonymous

    Prehaps developing the use of flexible glass for the display will allow for some flexing and help solve the encapsulation issue for OLEDs.