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.

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[Temporal Outcast]

More details can be found at Deisgntechnica.

Geekzone also has a similar article.

Interlacing is used to reduce flicker

[GillBates0]

and does not have anything to do with the resolution. Infact, interlacing is sometimes called "interlace scanning", because the gun in the CRT draws alternate lines across the screen to reduce the visible flicker arising due to the time required to move the gun from top to bottom.

As usual, Wikipedia has a good article. To quote:

Interlacing is a method of displaying images on a raster-scanned display, such as a cathode ray tube (CRT), that results in less visible flickering than non-interlaced methods. The display draws first the even-numbered lines, then the odd numbered lines of each picture.

Re:Interlacing is used to reduce flicker

[shirai]

Interlacing is used to reduce flickering? I think not. It used to be used to reduce *bandwidth*.

An interlaced image refreshing at 60Hz (30 full fields per second divided by 2) is going to have the same flicker as a non-interlaced image refreshing at 60Hz.

This is actually a very complex subject to do with how people view images, resolution vs fields per second, what type of images you are viewing, movement vs. still images, etc. but in terms of reducing flicker, I would say, at the very least, the statement is deceptive.

In fact, one of the major problems with old Amigas running in interlaced mode was the annoying (you got it) flicker. This is because a horizontal line that was exactly 1 pixel would turn on and off every 60th of a second. So in this case, it would depend on how you defined the world flicker too.

To be fair, I think what you meant to say was that given the same bandwidth on a non-digitally compressed transmission and without digitally upconverting the signal, you can get 60 fields per second (at 30 frames per second) instead of 30 fields per second (at 30 frames per second) meaning that you will probably get less inter-frame flicker. But even this is deceptive because if you built televisions specifically for 30 frames per second, you could simply reformulate the glow on the screen to last an extra 1/60th of a second longer. But perhaps this is (a) hard to do and (b) back then they wanted the extra fields per second for smoother motion. By the way, a lot of the bandwidth savings doesn't apply to digital due to the way that digital compression works. This was a controversial point during the discussions on HDTV resolutions.

Fudge. I'm trying to cover all my bases here so I don't get flamed for not knowing what I'm talking about. Suffice it to say, interlacing and reduction of flicker do NOT walk hand in hand. It is simply one factor, of many, that comes into play.

Re:I'm Confused

[ivan256]

Isn't it about time we depricated the use of those silly acronyms we've bastardized to not mean what they originally meant anymore anyway? Wasn't VGA 640x480 at a mere 256 colors? And didn't it imply a particular ISA bus interface as well? Plus, who can keep track of what WUXGA and QWVGA and UHDWMRXGA all mean? Was somebody just leaning on the keyboard, or did they mean to say something anybody could understand like "1600x1200"? Tell us the resolution in a way that doesn't require a lookup in a massive acronym table please. That way it will be easy to compare displays to each other.

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.

Article missing critical technical information

[francisew]

Here is a link to the Samsung website about the technology: http://www.samsung.com/Products/TFTLCD/Technology/ 4colorrandering.htm

I wouldn't complain too hard about the confusion in the details. They couldn't even spell 'rendering' right on their own site (4 color randering???).

It also discusses 'physicail' pixels. I dunno about that.

They seem to have created smaller pixels, which are spatially located across a different area than normal.

They then need fewer wires to connect the given number of pixels. Meaning a higher resolution with fewer interconnects. Maybe I'm completely wrong in this 1 minutes evaluation.

The neat thing is the overlap of their 'logical' pixel arrangements. It would seem they are using traditional dithering with a complicated arrangement of pixels. This should do exactly what they state. Ther weird thing is that their sub-pixel seems to have the wrong number of color sub-elements.

One would expect a ratio of 2:1:1 for green:red:blue emitters. They have 4:2:1. Maybe their red emitters are much brighter than the blue, which would make sense.

They mention replacing some rows with white pixels, but their diagrams don't show anything. Maybe the media-relations people just don't know how the technology works, and are making stuff up until someone corrects them.

Re:Nothing is impossible

[stonecypher]

Because current LCD pixels require six lead lines, and we can't make lead lines small enough to shrink the pixels any further. The article phrases this badly: it's not that pixels can't be made smaller. It's that TFT LCD pixels' lead lines take all of the available current space, and there is no current technique on the horizon to solve this. Other monitor types do not have this particular problem; this is peculiar to LCD and OLED.