Samsung to use Sub-Pixel VGA Screens

pdawerks writes "Samsung Electronics has developed a new graphics chip that will allow half VGA screens to produce VGA resolution. The novelty is specially aimed at future mobiles with VGA screens that will be less than 2.4 inches. It generates color using an entirely new driving method called sub-pixel unit driving methodology." Not sure if I think it is exactly new or not, but it's nifty.

Comments

It's not subpixel as with ClearType !

[GrAfFiT]

The article suggests that they added "White pixels". Additionally, the problem of dark screen due to the increased pixel density on high resolution panels has been solved using 4-color (R-G-B-W) rendering algorithm, improving the brightness of TFT-LCD panels. That's radicaly different than ClearType. ClearType uses the normalized RVB subpixels arrangement to triple the "perceived" resolution. That's because the humain eye is more sensitive to luminance than to chrominance (try to recognize colors in the dark, you can't, but you can still read B&W text). The problem here is not text aesthetics. It's global luminosity, as your backlight often has to battle with sunlignt. They add more "white pixels" to enhance the luminosity. In percentage, the number of "color" pixels are lower in this system. But the eye won't actually see the difference.

Re:It's not subpixel as with ClearType !

[shirai]

Note that white pixels aren't a magic bullet. You get some brightness but give up saturation. It works like this:

Given four pixels of RGBW, you can get your brightest color by having all four pixels on. This would result in total brightness of:

1 white pixel for every combination of RGB and

1 white pixel for every white pixel.

So you get the equivalent of 2 white pixels for every 4 pixels or a factor of 1/2 let's say.

In regular RGB, you get a factor of 1/3 because you get the equivalent of 1 white pixel for every set of RGB pixels.

Looking at this, you get 50% more maximum brightness from RGBW vs RGB.

It's not a magic bullet because you lose saturation. For example, if you want a fully saturated red, in the RGBW format, you get 1 full red pixel for every four pixels. In RGB, you get 1 full red pixel for every three pixels. So RGBW gives a factor of 1/4 while RGB gives a factor of 1/3 for a fulls aturated red. This is a reduction in brightness of a full saturation red of 25%.

In other words, your brightest color is 50% higher in RGBW but you brightest red (at full saturation) is 25% less which means you have to fudge around with values to get a picture that seems to make sense or you get a bright picture with dark spots with a lot of saturation in them. So you might, programatically (and this is probably what samsung is doing) increase full saturation red to include white in it. This makes the color brighter but also reduces the saturation.

A lot of projectors with a white component have two modes. A dimmer mode that doesn't use the "W" pixel at all but has richer colors (used for movie viewing) and a presentation mode that does use the "W" when brightness is a factor such as in a meeting (e.g. the room may have light leaking in from windows).

Not saying it is good or bad. Just that a RGBW is not a magic bullet.