[iPhone X Teardown] Apple's Strong Preference for Full-face Display (4)

2018/01/18 11:15
Norio Matsumoto
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Continued from [iPhone X Teardown] Apple's Strong Preference for Full-face Display (3)

In this way, in the case of odd-shaped panels, the number of items that need to be considered at the time of designing a driver circuit increases, compared with normal rectangular panels. If a driver circuit is designed without giving consideration to the new items, yield decreases at the time of manufacturing.

Same Pixel Layout as Galaxy

When observing the surface of the iPhone X's OLED part, we found four sub-pixels with different sizes. This pixel layout is very similar to that of the OLED panel of Samsung Electronics Co Ltd's "Galaxy Note8" smartphone.

The sub-pixel layout of the iPhone X
The "PenTile" pixel layout was employed as in the case of existing OLED displays for smartphones. The PenTile layout can improve the virtual resolution of a display having a wide pixel pitch. We found that the size of the blue sub-pixel is larger than those of the other sub-pixels. By reducing current flowing in blue sub-pixels, Apple probably slowed the speed of the deterioration of blue sub-pixels, addressing the problem of the color change of OLED display. (1) and (2) in the image are the widths of pixels. (source: Touch Panel Laboratories Co Ltd).

The sub-pixel layout of the Galaxy Note8

The pixel layout is called "PenTile." It is a technology to improve "virtual resolution" with a small number of sub-pixels by sharing some sub-pixels of adjoining pixels. It can reduce the total number of pixels, contributing to improving the yield rate of panels.

In the past, some people predicted that Apple would not use the PenTile and would employ the RGB stripe layout as in the case of the LCD panels of previous iPhones. The RGB stripe layout uses three RGB (red, green and blue) sub-pixels as one pixel and does not share sub-pixels.

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