View Full Version : 3D and Plasma Tech Question


Brian Siano
10-20-08, 10:36 AM
I'm taking the HD plunge in the next few months, but there's a question I have about future 3D television technology.

As i understand it, LCD sets with 120hz refresh rates are well-suited for 3D, because they can run the left-and-right signals at 60hz. That's fine, and it's a good reason to consider LCD sets.

However, plasmas apparently don't need to use a feature like 120hz refresh rates. I don't quite understand the reasons why (and an FAQ'd be appreciated). But my question is whether plasmas will be capable of the speed or refresh rates required for good 3D displays in the future.

Thanks for any insights you can spare on this question.

xrox
10-20-08, 11:11 AM
I've recently read that LCDs have issues with 3D. LCD viewing angles variations play havoc with 3D perception.

As far as 3D and PDP refresh goes, I'll try and look that up fo you.

Cheers

optivity
10-20-08, 11:35 AM
plasmas apparently don't need to use a feature like 120hz refresh rates. I don't quite understand the reasons why (and an FAQ'd be appreciated)"Response time of a display technology is important in several ways but the most important is the image “lag” on screen in fast moving video or graphics. LCD displays have been the main focus of this criticism. Typical plasma displays respond similar to CRTs in nanoseconds compared to the longer milliseconds for LCD. A slower response time causes the “lag” we see when viewing fast moving video on an LCD screen, but this gap between plasma and LCD is closing to the point that in the best LCD displays “lag” becomes unnoticeable. The newest versions of LCD displays are rated at 8ms or 6 ms and some as fast as 3ms in their rise and fall response time. The remaining problem here is that the response time numbers can be misleading. It depends on how the manufacturer measures the rise and fall of the LCD response as to how it actually affects the fast moving images on screen. All things being equal, plasma displays still have the edge when it comes to response times."

(source: Plasma Versus LCD and the Winner Is……. (http://www.isfcommercial.com/docs/Plasma%20vs%20LCD.pdf) by ISF Commercial (http://www.isfcommercial.com/))

Brian Siano
10-20-08, 03:20 PM
"Response time of a display technology is important in several ways but the most important is the image “lag” on screen in fast moving video or graphics. LCD displays have been the main focus of this criticism. Typical plasma displays respond similar to CRTs in nanoseconds compared to the longer milliseconds for LCD. A slower response time causes the “lag” we see when viewing fast moving video on an LCD screen, but this gap between plasma and LCD is closing to the point that in the best LCD displays “lag” becomes unnoticeable. The newest versions of LCD displays are rated at 8ms or 6 ms and some as fast as 3ms in their rise and fall response time. The remaining problem here is that the response time numbers can be misleading. It depends on how the manufacturer measures the rise and fall of the LCD response as to how it actually affects the fast moving images on screen. All things being equal, plasma displays still have the edge when it comes to response times."

Hm. I guess I was misled when I'd see the specs on plasmas, and see references to 72hz refresh rates and such-- mainly to show that they can refresh at a rate that's a multiple of 24. So I figured that plasmas couldn't do 120hz, but there was some other quality that made up for that.

If plasmas have a refresh rate that much faster, then, how fast can they go? And could they manage future 3D requirements?

ccotenj
10-20-08, 03:32 PM
2 different things brian...

optivity
10-20-08, 03:45 PM
http://mysite.verizon.net/vzequg9f/engadgethd-1080p24.jpg

Brian Siano
10-21-08, 10:01 AM
The replies above are pretty interesting, but I still have questions. The article Optivity cited explains why many HDTVs don't properly display 24fps media properly. Now, I understand why that's relevant to watching most films, and it's something for me to look for when I'm shopping.

From what I can tell, however, plasmas don't seem to have any problems matching refresh rates in the 72hz range, and maybe even faster. However, from what I can tell, 3D displays will require even faster refresh rates: they have to present two video images, and it's desirable that each of these have a high refresh rate, too.

So on an LCD, a 120mhz refresh rate means that both signals will be displayed at 60hz; not perfect, and probably requiring some pulldown or other legerdemain, but perfectly serviceable. My question is whether a plasma would be capable of matching this performance.

xrox
10-21-08, 10:30 AM
So on an LCD, a 120mhz refresh rate means that both signals will be displayed at 60hz; not perfect, and probably requiring some pulldown or other legerdemain, but perfectly serviceable. My question is whether a plasma would be capable of matching this performance.Historically, plasma displays we're not capable of higher refresh rates because the discharge delay was too long thus limiting the addressing speed. The move to 1080p and single scan systems put even more limitation on addressing speed and brightness.

However, recent advances have reduced the discharge delay significantly enabling 100Hz and 120Hz operation at 1080p with good enough brightness. Pioneer technology along with high lumen tech will enable even faster and brighter systems in the future.

xrox
11-04-08, 04:01 PM
Brian, check this LINK (http://code.chinafpd.net/code2008/meetingfiles/FPD/523/Samsung%20SDI_The%20Future%20of%20SDI%20PDP%20Technology.pdf ) out starting at page 31