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

Anyone?

[wankledot]

This sounds exactly like sub-pixel antialiasing, which is the basic for lots of things, including OS X's font smoothing on LCDs, and Microsoft's type technology... I forget its name.

Is it really as simple as that? because that's been around for at least 25+ years in theory, a bit less in practice.

All new technology? Unlikely

[ikewillis]

Subpixel rendering has been around for quite a long time. Two things that I can think of right off the bat are Microsoft's ClearType and FreeType, both of which have hinting engines which support subpixel rendering.

Subpixel rendering takes into account the physical position of the red, green, and blue subpixels of an LCD display, and can therefore provide up to 3X the horizontal resolution of a typical display (with distortion, of course)

Here's a nice writeup

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.

I wrote a program to simulate it

[Dink Paisy]

I know this is so late that everyone has moved on to the next story, but curious about the idea, I wrote a program to simulate the idea using my shadow mask CRT monitor, and compare it to downsampling and true 640x480. It may work on aperture grill and LCD monitors as well, but it probably won't look as good. Download here. Sorry; it's a windows binary only, and it requires .NET.

For best results set your resolution low, otherwise it has very visible moire patterns. As a side effect of the conversion, the image gets darker. My program also has a colour cast, which the article claims is due to adding the white pixel. The article also says that Samsung has overcome this problem.

It works by setting up the subpixels as a 640x480 square grid, with each pixel consisting of a starting pixel, and the right, lower, and lower right subpixels. Subpixel values are calculated using the average intensity of the corresponding colour value in each of the four pixels the subpixel is a part of.

Visually, aside from the darkness and colour cast which are artifacts of the simulation and wouldn't appear in the real product, it looks decent. It's blurrier than a true 640x480 display, but retains more detail than the 320x240 downsampled version.