Not all RGBW Displays are Created Equal

Perhaps you may have noticed that LG introduced an RGBW OLED TV at CES, using a white OLED process together with traditional RGB+Clear color filters.

The purpose of this was ostensibly to facilitate the manufacturing of a large diagonal OLED, that is traditionally difficult with shadow mask deposition techniques.  My assumption is that they used RGBW to enhance brightness, taking advantage of their white OLED material to attain the longer 30,000 hours or more of  lifetime which is now expected for TVs.  At CES I was told that the layout was a QUAD layout, which uses 4 subpixels per pixel, unlike PenTile that uses, on average, 2 subpixels per pixel achieved through subpixel rendering.

Similarly, we are also seeing additional announcements of products by Sony using their Sony Whitemagic™ technology.

The layout of RGBW for Whitemagic also has used 4 subpixels per pixel unlike PenTile’s 2 subpixels per pixel on average.  While Sony’s stated purpose for Whitemagic has been to enhance power efficiency, a 4 subpixel per pixel layout only take advantage of the improved light throughput of clear subpixels.  It is, no doubt, an improvement to power efficiency, but it forgoes the chance to improve aperture ratio, which a significant part of what is achieved with PenTile technology.  As one moves to increasingly higher resolution formats aperture ratio becomes a major limitation, even for low temperature polysilicon (LTPS) backplanes.  For PenTile, however, the contribution of improved efficiency in our highest resolution designs is equally attributable to improvements in aperture ratio as well as the improved throughput gained from clear color filters.

Competitive RGBW is a step in the right direction, but there is no substitute for genuine PenTile technology.

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