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Making LCD Displays Snappier
newSlashUser points out a very interesting article at ExtremeTech about a new means of more quickly
controlling LCD panel response, so the old complaint that LCD panels make poor displays for gaming and high-motion video may be whittled down a bit. As a bonus, the change is all in the controller, so it doesn't require any change in the way the panels are manufactured.
is the fixed resolution they come with. Many applications I use for 3D require at a minimum 1280X1024, but work best at 1600X1200. So I wouldn't say that slow draw is the only problem, as this site states.
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The number of areas where CRTs were superior to LCD displays continues to dwindle. It used to be they were only smaller/lighter. But in exchange for that, you paid 4x as much, and if you typed faster than 40wpm all you'd see is a grey smudge for 15 seconds (I remember the monochrome, passive matrix screen on my Powerbook 145b). Now the prices are becoming dollar-for-dollar competitive with CRTs, they are still smaller/lighter, and now they might actually be able to handle Quake 3 Arena and look as good as my 20" monitor (and yeah -- they are pretty close to that now, especially with a still image, but...). I think the days of the CRT really are numbered this time around.
If you can get your LCD controller to run at 60-80Hz, you should be able to implement this technique in software: compute change-corrected frames, where the ``feed-forward'' bits disappear faster than the human persistence rate. There's plenty of CPU for this, and the psychovisuals help: any reasonable transient errors in the LCD response are likely to be masked by the fact that the changing pixels are likely changing due to motion...
I had always just sort of assumed that controllers already did this, since it's so obvious. Even better would be to have the controller actually measure the pixel modulation (which it it should be able to do using the same mechanism it uses to change it) and use feedback, which would likely provide even faster response.
Sadly, at the end of the day, the 40Hz limit on skewing reasonably priced panels over the full range will continue to be a problem. With feedback and feedforward techniques, can one use higher pixel modulation voltages to improve this as well? I don't know, but I would guess one could...
Organic LEDs are on the way in probably about 5 years or so, and I am willing to wait for them. Cheaper to produce, no backlight, and flexible. Production screens for cell phones and camcorders are being produced, so it's only an engineering step to up-size them. They are also more durable and scaleable than LCDs.
It's nice that LCDs are getting better, but even better stuff is just down the pike.
Vote monkeys into Congress. They are cheaper and more trustworthy.
Two polarizing filters encase the liquid crystals in the LCD. One filter is etched with horizontal lines; the other with vertical. Light enters the liquid-crystal compartment parallel to the first filter's lines and follows the path of the liquid crystals. If the liquid crystals become energized, the crystals and light rays do not twist to become parallel with the second filter. Light rays reach the second filter perpendicular to its lines and cannot pass through to the viewer's screen image. If the crystals are not energized, they twist themselves and the light rays to allow light to pass through and illuminate the LCD.
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taken from
http://www.smartcomputing.com/editorial/article
--- Metamoderating abusive downgraders since my 300th post.
As others have pointed out, the LCD stops the transmission of light when voltage is applied, hence giving you black.
But one other nit-pick: "I don't understand why you need power to produce black" - No you don't need power. You need Voltage. The LCD cell acts like a capacitor and does not pass DC electricity though it. So no current, and hence no power used.
Leakage would probably be in the micro-amp range.
--jeff
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Apple's LCD displays are probably the best that exist, beating out SGI by a large margin. I've never had a moment's problem playing Quake or Unreal Tournament on my TiBook or G4, using either the Studio or Cinema display.
Perhaps the solution isn't more hacks, but better hardware. Sure, it comes at a price, but I'd rather drop an extra couple hundred for something that actually works.
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I think LCDs could be improved a little bit in the dark color range. Unlike a CRT, which is a black surface on which color is added, LCDs are a white surface on which color is subtracted by blocking the light.
IMO, the image on LCDs already looks a lot better than that of CRTs, and doesn't fatigue me as much. In fact, no matter what refresh rate I was using with my CRT, I could always see the flicker for some reason. My eyes actually hurt after looking at the monitor for a few hours. This problem got worse proportionally with larger displays, so graphical work was always very tiring. The LCD fixed that. Yes, there is a refresh rate, but it works differently than that of a CRT, so I cannot see the LCD refresh.
I think the advantages of LCDs outweigh the disadvantage of slower animation. Most work I do is either textual (writing or coding) or graphical. There is rarely any fast action going on. (I occasionally play Quake II, the only game I ever bought, but with a CRT. I just don't play for very long. Why should I? There's so much to life that if I'm not working, I prefer to do things unrelated to computers.)
As for television (and this is a weak argument as I rarely watch TV), I think LCDs already accomodate that format quite well. The colors look great. Yeah, fast action isn't as good, but oh well. :-)
Like I said before, the only thing I would improve about the LCD is its reproduction of really dark colors--that is, better blocking of the light.
My time spent with Philips Flat Displays in Philips Components allowed me time to see this and many other LCD-ish technologies. If you look here at the papers about Motion Compensation, that is the stuff I saw, and in fact, our group was working on the drive electronics to make it work. David Parker, one of the authors on a couple of those papers, is a very cool guy, as were all of the guys at PRL in Redhill, England.
Unfortunately, the LCD panel business slipped into commodity mode too quickly, where 15-inch panels and the displays containing them had to be super-cheap, and that was where Philips wanted to be, so we tabled the project. The simulations, though, showed a drastic difference is clarity and response time, resulting in sharp images suitable for television or video gaming.
As an aside, someone asked about applying voltage to get black. This works best with active matrix displays, while passives use the normally-black approach (apply voltage to get white). If you remember your old laptop displays from back then, dark vertical lines in dialog boxes and the like created vertical lines that ran the height of the screen thanks to voltage leaking to all of the dots in a column, which is not a big problem for actives.
There is a lot of cool stuff in the future of displays. LCD tech of today sorta sucks/ Look for some very cool stuff in multidomain displays and OLED/PolyLED displays.
teh way lcd screens work is (through magic) they seperate the white backlight into vertical bands of red, green, and blue (not necessarily in that order).... so you have three sub pixels per pixel, each one is individually controlled.
(that is what microsoft's cleartype(tm) leverages... since, the order of the subpixels are known, you can render to individual subpixels by using color values... and stuff)
(grc.com has a better explination of cleartype)
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20 January 2017: the End of an Error.