- [KIPOST] FlexiGO, "Galaxy Fold is Able to Endure 265,741 Folds"
- The part where defect starts occuring after 160,000 folds is driving system, not OLED
The durability limit required for foldable Smartphones is usually 200,000 folds. Assuming that the device is going to be used for about five years, it must endure 100 folds a day. Samsung Electronics also announced that it has tested its smartphones for 200,000 folds and unfolds in a video clip released along with the release of the Galaxy Fold.
Then if the real device is folded and unfolded for 200,000 times, what process would lead to a defect? This question can only be answered by operating a testing equipment for foldable device.
– Galaxy Fold withstands 265,741 folds
FlexiGO, an evaluation equipment manufacturer specializing in foldable Smartphones and displays, recently conducted durability tests on two Galaxy Folds. FlexiGO's 'Foldy' is an equipment that measures in real-time how waviness and brightness change during repeated folding and unfolding of the device.
FlexiGO tested the device by folding and unfolding Galaxy Fold every two seconds. The results showed that the display of the Galaxy Fold worked normally during 265,741 folds. It is even more than the required 200,000 folds mentioned earlier.
Lee Ki-yong, CEO of FlexiGO, said, "The condition of the display remained almost perfect even during about 260,000 folds." "However, the device malfunctioned due to a defect in the driving system," he explained.
The driving system here does not mean the backplane (TFT) that acts as the switch for the display. Like OLED organic layer, the backplane passed 200,000 folds test easily. However, it is speculated that the defect was caused by the bending of Flexible Printed Circuit Board (FPCB) or chipsets related to displays located near the hinges.
It is noteworthy that while Galaxy Fold's OLED display endures 260,000 folds, it shows abnormal signs in brightness from about 160,000 folds.
The Galaxy Fold's screen, which had maintained a uniform 300cd/㎡, began to show disparities by part after 160,000 folds. At 240,000 folds, just before the screen turned off, brightness of certain parts of the display were measured at up to 310cd/㎡.
CEO Lee said, "This malfunction is not a defect in the display itself, but the faulty driving system seems to have affected the operation of the display." "The OLED itself will be able to withstand 300,000 to 400,000 folds," he analyzed. In order to strengthen the durability of the Galaxy Fold in the future, it may be necessary to redesign the driving system in addition to the screen.
The bends in the folding part of the screen was not a concern. This means that there was a noticeable bend, but that did not pose a problem in using the device.
According to the test results, the screen curves, which was initially measured at 10~30μm, has increased to 30~60 μm after 200,000 folds. However, no defects such as crack or peel were found in the screen protector (changeable window) surrounding the screen.
CEO Lee Ki-Yong said, "There was a curve that could be seen with the naked eye, but there was no problem with the display function, and there was no problem using the device."
FlexiGO's durability test was conducted at room temperature and average humidity. It recently started durability tests in high temperature of 60℃ and high humidity of 90%. Since OLED is vulnerable to oxygen and moisture, the display is more likely to cause defects in environments with high temperature and high humidity.
Source: KIPOST(https://www.kipost.net) / Journalist Ahn, Seok-hyun (email@example.com)
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