Re: Headache, bad for eyes LCD displays

Once again Jeff, you rule!!!
Your info is ALWAYS soo good, even if I didn't need any of this
info right now, I was glad to read up on what you had to say about it.

I'm on a CRT Flat Screen Display Sony Monitor and am currently
running at the default 60hz, so am I running too low or can I speed mine up?

BTW, thanx a zillion for all the help you gave me with info about my MoBo and RAM issue.
I truely appreciated that more then you know :)
I did decide to just leave things alone and not bother with changing anything.
I'm just going to split up the left over RAM sticks between my other
machine and maybe a little one for just render node use.

Anyway, this topic was a good one, as some day I plan on moving into a flat panel monitor.

Thanx!...................................md :)


DarkScience wrote:

"Steve Reeves" <steve@xxxxxxxxxxxxxxxxxx> wrote in message news:dr7f6j$931$1$8300dec7@xxxxxxxxxxxxxxxxxxx


Does the refresh frequency make any difference to LCDs if they are running from analogue signal?



Refresh on an LCD panel is a different animal... You have the backlight, which is a 60Hz fluorescent lamp and that is a constant that doesn't change. The panel itself will also have one or two refresh rates and the typical are 60Hz (all LCDs operate at 60Hz, or at least all I know about) and occasionally 48Hz. Some LCD displays have the ability to accept signals at higher scan rates, for compatibility reasons, but they still refresh the displayed image at 60Hz. A few of the very new HDTV LCOS displays (like the new 65" model from Brillian and the >$20K pro models from JVC and Sony) now have 120Hz refresh rates. But don't plan to see that on large panel desktop monitors anytime soon. These are 1/2 to 2/3 inch LCOS chips. 120Hz for LCD and other non scan-line generating displays is the ultimate target. 120Hz will provide smooth video playback for 120, 60, 48, 30 and 24 frames per second. Current 60Hz displays have playback "judder" on 24 and 48 frame/sec media. Makes it hard to edit 24fps HD and film sources without having a CRT display or one of those super-expensive LCOS displays. Some studio-grade LCD desktop monitors also support 24Hz and 48Hz refresh to facilitate this sort of editing...

LCDs don't need the high refresh rates in order to deliver a smooth image in normal circumstances because there is no horizontal or vertical scanning, the entire display simply refreshes at once, all pixels simultaneously. The response time you see (6, 8, 11, 12, 16 milliseconds as industry norms) is measured differently from one manufacturer to the next, but it is usually the time it takes for the display pixels to go from 0 black to 100% white and back down to 0. Obviously, the faster the better as it eliminates motion blur. Anything faster than 16ms is ideal for video and gaming and the eye can still detect differences down to about 8ms. Faster than that is somewhat of a waste. On a CRT this same effect is called phosphor persistence. Trinitron style displays have phosphor rise/fall times approaching in the 3 to 5 ms range. Shadow mask displays are usually in the 6 to 9 ms range. But just as with LCDs there's exceptions to these... I've seen junk LCD monitors that have 22ms respnses and they're blurry as all *%&#$ when playing Quake.



I must admit, I assumed that it didn't because of the refresh rates of the screen - 12ms and so on. I am running my secondary monitor off a DVI port with an adapter so that I can fit the second monitors VGA cable into it and so it is not digital. Will increasing the frequency (when I install the right driver!) make a difference?



No difference for the on-screen refresh. However, it may make a difference as to how the monitor processes the incoming video signal and how that translates to what transitions to the screen.

You also have to figure that on digital connections (DVI/HDMI), there are limitations to refresh rates within the standard. Partially due to conformance, but also bandwidth limitations. The current top resolution for DVI/HDMI is 1920x1200 @ 60Hz. A dual-link connection supports up to double that and for 16:10 aspect, a 2560x1600 @ 60Hz is about the best you can get. Looks damn nice too on the Dell and Apple 30" displays.






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Check out my Tutorials:

MD arts
Mark Dunakin
md@xxxxxxxxxxx
http://www.md-arts.com .

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