Brad Molen, Engadget:
Suffice it to say for this review, the Epic 4G Touch doesn’t disappoint in its display either. We say this with just a smidge of surprise, since it made the screen even larger but yet used the same WVGA (800 x 480) resolution. The pixel density is obviously lower in this case, as there’s more screen space to pack the same number of pixels in. To our delight, however, the Epic’s display looked just as beautiful in spite of the size difference. This was great news to us, since we were able to enjoy the same viewing experience and do so with more real estate on the screen. And what’s better, we took the phone outside in the middle of a sunny day and were still able to see the screen clearly, despite being exposed to direct sunlight.
The Samsung Epic 4G Touch sports a 4.52-inch Super AMOLED Plus display with a RGB stripe 800×480 pixel format resulting in a resolution of 206.41 ppi. Let’s compare the resolution to the ‘regular’ Samsung Galaxy S II that features a slightly smaller 4.27-inch Super AMOLED Plus display but with the same pixel format. The resolution? 218.49 ppi. Do you think most of us can distinguish the 12.08 ppi difference? Probably not. It’s unsurprising that the slightly larger 4.52-inch Super AMOLED Plus display on the Samsung Epic 4G is just as good as the smaller one.
But the performance in direct sunlight is quite surprising. Out in direct sunlight it is difficult at best to clearly see content on a transmissive LCD or an emissive OLED display. Even with anti-reflective coatings, an optically laminated cover glass to eliminate refraction, and an extremely bright display, etc. performance in direct sunlight is poor. Only displays with reflective properties perform well. I’ll chalk this result up to Molen exaggerating a little bit. The Samsung Epic 4G Touch is probably viewable in direct sunlight, and not as bad as one might have expected from a smartphone with an OLED display.
To take things an extra step, we compared the Epic’s Super AMOLED Plus side by side with the IPS WVGA display in the T-Mobile G2x, cranking the devices’ brightness up as high as they could go. The G2x, which has a higher pixel density by nature of its 4-inch display, still appeared dimmer and more pixelated.
Now this at first is weird: how can the T-Mobile G2x appear more pixelated when the 4-inch 800×480 IPS LCD sports a resolution of 233.24 ppi? The G2x has a resolution that is 26.83 ppi denser than the Samsung Epic 4G Touch. Then it came to me.
OLED is an emissive technology. Think CRT or plasma. If you take a very close look at those pixels they are somewhat fuzzy at the edges. This isn’t necessarily a bad thing since it makes the edges smoother and closer to how things look in real life. But it isn’t the best if you’re working on the latest CAD drawing that requires precision.
LCD on the other hand is based on a mechanism that uses liquid crystals to control light that passes through square shaped pixels made up of three rectangular shaped sub-pixels*. The edges of a LCD pixel are sharp. Again, this isn’t a bad thing: LCDs are generally a whole lot better for watching computer generated films such as Pixar’s Wall-E for example. But that razor sharp edge could look more pixelated if the pixels aren’t small enough at a particular usage distance.
So that explains the initially troubling conclusion. The Super AMOLED Plus display on some Samsung smartphones can look less pixelated even at lower resolutions due to the emissive nature of OLED technology that smooth things out at the edges.
The Samsung Epic 4G Touch with the larger 4.52-inch 800×480 Super AMOLED Plus display looks fantastic, just as good as the smaller 4.27-inch version, and better than some LCDs with a higher resolution.
* In general. There are other sub-pixel structures pioneered by Clairvoyante (now Nouvoyance) such as RGBW, RGBG, etc.