4ms Displays Around The Corner

[pakotlar]

Viewsonic is releasing their new VX line of LCD's, and they are purported to run 4ms across the entire color range. Now this is a PR release, but interesting nonetheless.

For reference I believe that Phosphor response time (CRT's) is ~ 2ms. This is OTOH.

Check it out http://www.viewsonic.com/xtreme/.

 

[suryad]

Wow

 

[Nite_Hawk]

Looks good, though I have a couple of questions:

1) What are their tolerances per transition? How close do they need to get to a target grey level before they claim that it's "good enough"?

2) Is this the time it takes to go from one grey level to the next and back, or just from one grey level to another? Most manufacturers list their response times as white to black to white or black to white to black, which obviously takes longer than white to black or black to white.

3) They say it takes 4ms on average across the entire color space per transition. What are the upper and lower bounds and for what color ranges? This is better than just quoting the best cases like most manufacturers do, but it still could mean most transitions are < 4ms while a couple of cases are significantly worse.

Other than that though, the displays look very good. I'm curious if they are using the feed-forward technology that was supposed to appear a year or two ago. Based on the way they are marketing it I'm guessing they are using it or something like it.

Nite_Hawk

 

[Sxotty]

As long as they are measured in the same way as the old viewsonic monitors than it is still significant progress...

 

[mczak]

The VX924 and VX724 are the first desktop displays to combine ViewSonic’s proprietary Dynamic Structure™ and Amplified Impulse™ video response acceleration technologies

"Amplified Impulse" sounds to me like they are using a method also known as "overdrive" (that is, when transitioning from dark gray to lighter gray, which would take ages, you apply the voltage corresponding to white for an initial short duration).
Sounds good to me, it's not quite a very new trick, but displays which use it are still very rare.
Though no mention of display technology, are they still using TN+film as is usually the case with these fast displays? I'll be impressed when I see a 1600x1200 20" MVA display with 4ms switching time at an affordable price, I'd probably even buy it

 

[pakotlar]

The VX924 and VX724 are the first desktop displays to combine ViewSonic’s proprietary Dynamic Structure™ and Amplified Impulse™ video response acceleration technologies

"Amplified Impulse" sounds to me like they are using a method also known as "overdrive" (that is, when transitioning from dark gray to lighter gray, which would take ages, you apply the voltage corresponding to white for an initial short duration).
Sounds good to me, it's not quite a very new trick, but displays which use it are still very rare.
Though no mention of display technology, are they still using TN+film as is usually the case with these fast displays? I'll be impressed when I see a 1600x1200 20" MVA display with 4ms switching time at an affordable price, I'd probably even buy it

hah, well yeah, i would like that too

 

[ANova]

Grey to grey is 4ms while black to white is 5ms.

 

[Nite_Hawk]

Grey to grey is 4ms while black to white is 5ms.

This is why we think they probably are using the feed-forward technology (or Amplified Impulse/Overdrive as mczak put it). gray to gray transitions should end up being faster than white to black transitions as it takes less time to raise or lower the voltage to the intermediate state so long as you get the timing right and cut it off at the correct grey level. Traditionally you have to worry about stablization time, but with these kinds of displays that is not the case.

Should be interesting to see it in action. Since it's an electronic enhancement rather than a panel enhancement, these kinds of displays shouldn't be significantly more expensive than traditional ones now that they appear to have it working correctly.

Nite_Hawk

 

[ANova]

Since it's an electronic enhancement rather than a panel enhancement, these kinds of displays shouldn't be significantly more expensive than traditional ones now that they appear to have it working correctly.

Nite_Hawk

They are set to be launched at only $40 more then their current panels, so you would be correct.

 

[Mintmaster]

This is why we think they probably are using the feed-forward technology (or Amplified Impulse/Overdrive as mczak put it).

I've always wondered why they didn't do this a long time ago. If LCD pixels are slow to switch, why not just jolt them with a pulse? I figured the difficulty had to do with being able to control the timing on a fine time scale for all pixels. Maybe they're able to address each pixel over a small time scale now, like <1ms. Hopefully there won't be any overshoot problems.

 

[Nite_Hawk]

This is why we think they probably are using the feed-forward technology (or Amplified Impulse/Overdrive as mczak put it).

I've always wondered why they didn't do this a long time ago. If LCD pixels are slow to switch, why not just jolt them with a pulse? I figured the difficulty had to do with being able to control the timing on a fine time scale for all pixels. Maybe they're able to address each pixel over a small time scale now, like <1ms. Hopefully there won't be any overshoot problems.

I'm curious about this as well. The technology has been known about for some time, and it was claimed that these displays would already be on the shelf. Apparently it must be more difficult of a problem to solve than they first thought. Still, if viewsonic has figured it out, it can't be very much longer until the other companies get products on the shelves. Between this tech and replacing the backlights with arrays of independent LEDs, LCD displays could be getting much much better (granted, the combination of the two techs could make for some interesting implementation challenges).

Nite_Hawk

 

[Fox5]

Will LCDs one day surpass CRTs in response times, or is that impossible?

 

[London Geezer]

Will LCDs one day surpass CRTs in response times, or is that impossible?

Nothing's impossible.

 

[Moloch]

Will LCDs one day surpass CRTs in response times, or is that impossible?

How would you rate a crts response time?
I know they have ghosting, like cds(but not nearly as bad), but what is typical rating?

 

[Sxotty]

In the link he had it said like 2ms I think...

 

[Nite_Hawk]

Will LCDs one day surpass CRTs in response times, or is that impossible?

How would you rate a crts response time?
I know they have ghosting, like cds(but not nearly as bad), but what is typical rating?

You can rate the response time of a CRT based on how long it takes for a phosphor to decay. CRTs can be built with very very short phosphor decays, but the problems is that the shorter they are, the more often you need to refresh the screen to avoid flickering. Displays with a short phosphor decay will appear to flicker worse at 60hz than a display with a long phosphor decay (but at the same time, the display with a short phosphor decay will ghost and blur less).

Ultimately, it's best to choose a phosphor decay that will not cause noticable ghosting, but will not appear to flicker badly (especially if you assume that most people leave their displays set at 60Hz).

Nite_Hawk