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Panasonic 2010 plasma: Floating blacks - Page 42

post #1231 of 1569
I don't buy that it is an Energy Star byproduct, that's what an untweaked Standard Mode accomplishes. But I could be wrong, I was under the impression that a mode had to be present that could pass the new energy standards and the TV didn't have to meet it at all possible setting configurations.
post #1232 of 1569
Since I've been using the LED lighting trick I've been very happy with the TV... a nice stable picture. The higher black is not that much higher than the "normal" level it's supposed to be. I just up the contrast a bit more to give the "illusion" of a deeper black level!

It doesn't take a large amount of light to trigger the sensor.... I'm just using a small rechargeable battery back with one LED resisted way down. It's focused right on that sensor. I'm seeing how many days I can get out of a charge.

It looks a little crude right now, but I think I want to make a little wooden box or something so it looks a little more "furniture" like.
post #1233 of 1569
I am of the opinion that CATS and "floating blacks" operate independently, but interact.

It seems that CATS only masks the effect by crushing blacks. When higher ambient light increases the black level, the average APL goes high enough that even the darkest signal will not hit a low enough APL to trigger the "energy saving/black level reducing" function, aka, "floating blacks".

Bottom line, you have to deal with floating blacks if you want the lowest black level these sets can produce.

An interesting side to this is that grey scale calibration should be done with care as these "floating blacks" could introduce interesting effects that require tradeoffs.
post #1234 of 1569
Im also of the opinion, when I buy into 3DTV, Ill be avoiding Panny's if they dont fix some of these issues. I love Panny, but having to troubleshoot a tv to get fix a PQ issue, is ridiculous.
post #1235 of 1569
Quote:
Originally Posted by Dayton View Post

I don't buy that it is an Energy Star byproduct, that's what an untweaked Standard Mode accomplishes. But I could be wrong, I was under the impression that a mode had to be present that could pass the new energy standards and the TV didn't have to meet it at all possible setting configurations.

I really didn't buy that BS from them for one second. It's a standard answer to get me off of the line. I told them I wasn't happy or satisfied with the way the set floated in no uncertain terms including asking why they would design a tv that exhibited such a major annoyance. She even said that now that I've noticed it I'll notice it more as your eye will pick it up more readily.

That answer pissed me off so they are going to fix my buzzing issue no matter what it takes because that can't be by design...
post #1236 of 1569
Quote:


Since I've been using the LED lighting trick I've been very happy with the TV... a nice stable picture. The higher black is not that much higher than the "normal" level it's supposed to be. I just up the contrast a bit more to give the "illusion" of a deeper black level!

Inspiring. I currently have a Samsung 50C550 that I bought because my S2 had bad floating blacks. It doesn't have exceptionally deep black level. I'm half-tempted to take it back and try a G25 with the LED trick. A panasonic with fully-floated blacks might have a comparable black level to my Samsung C500, and I feel that just about everything else about the Panasonics is better than my Samsung. Colors are better, IR is better, and quietness is better with Panasonics. Is there any way you can measure your LED-modded Panasonic so that I can compare it with Samsung black levels? Does anyone else have any input on which would have a better black level--a fully-floated Panasonic versus Samsung 50C550?
post #1237 of 1569
Quote:
Originally Posted by Camster View Post

I really didn't buy that BS from them for one second. It's a standard answer to get me off of the line. I told them I wasn't happy or satisfied with the way the set floated in no uncertain terms including asking why they would design a tv that exhibited such a major annoyance. She even said that now that I've noticed it I'll notice it more as your eye will pick it up more readily.

That answer pissed me off so they are going to fix my buzzing issue no matter what it takes because that can't be by design...

I think they do have some technical basis for stating this. Without floating blacks or rising blacks the panel would need to raise address voltage or width to compensate for impedence at high APL (floating blacks) or material changes over time (rising blacks). Raising address voltage or width will raise power consumption. Instead Panasonic messes with the initialization voltage to compensate which keeps the address voltage stable but has the drawback of shifting black levels.

That being said it still makes little sense because IIRC floating blacks have been a part of Panasonics well before power became important. And rising blacks can be compensated by having a higher black level to begin with.

So even though power is saved I still believe the main driver here is to maximize contrast at low APL (floating blacks) and at time zero (rising blacks).

If Panasonic is using the MgO single crystal (Pioneer CEL) then according to the Pioneer document on this the single crystal material should eliminate the need for floating black and/or rising black.

See the following posts for more info:
Floating Blacks Explained
Rising Blacks Explained
post #1238 of 1569
Why don't the blacks float on all Panasonic's 2010 models? I have an S2, which floats. My parents have an X24 (Costco model) and the blacks do not float.
post #1239 of 1569
Quote:
Originally Posted by buckchester View Post

Why don't the blacks float on all Panasonic's 2010 models? I have an S2, which floats. My parents have an X24 (Costco model) and the blacks do not float.

I suspect it may be that the X24 is not a Neo-PDP panel which might explain it.
post #1240 of 1569
Quote:
Originally Posted by Camster View Post

I suspect it may be that the X24 is not a Neo-PDP panel which might explain it.


I think you are correct. Seems like some problems were made worse with NeoPDP. I never saw color banding or FB's on my 2008 50" 85u.
post #1241 of 1569
Quote:
Originally Posted by ElwayLite View Post

I think you are correct. Seems like some problems were made worse with NeoPDP. I never saw color banding or FB's on my 2008 50" 85u.


Yes, the 2008 and 2009 did not have noticeable floating blacks. But the 2007 models did. Maybe xrox has some words of wisdom about this.

Larry
post #1242 of 1569
Quote:
Originally Posted by LarryInRI View Post

Yes, the 2008 and 2009 did not have noticeable floating blacks. But the 2007 models did. Maybe xrox has some words of wisdom about this.

Larry

My old Panasonic ED Plasma (2004?) had floating blacks. There are threads in the archives discussing floating blacks as early as the 7UY models I believe. This is why I tend to believe that power was not the driving factor (at least not initially).

Do you guys remember what year the first 1080p Panasonic plasma was available? Also what year was the first NeoPDP available?

The reason I ask is that the patents mention that smaller pixels (ie - 1080p) required higher power and higher light emission [NeoPDP] requires higher Xenon Gas content [part of NeoPDP] which required more voltage.
post #1243 of 1569
My 2008 was not a Neo, and I thought they started in 2009.
post #1244 of 1569
The PX600U had a 1366 x 768 screen. The PZ700u had a 1920 x 1080 screen.

EDIT: Yes, I think the neoPDP was introduced last year -- the 2009 models.

The px500u was 1366 x 768 also.

Larry
post #1245 of 1569
Quote:
Originally Posted by xrox View Post

My old Panasonic ED Plasma (2004?) had floating blacks. There are threads in the archives discussing floating blacks as early as the 7UY models I believe. This is why I tend to believe that power was not the driving factor (at least not initially).

My 657UY had unstable black detail until I got some help from an insider at Panasonic that helped my change some hex values in the service menu.

Displaying 5 and 10% patterns would loose detail after a few seconds.
This may not have been the floating blacks problem though.

I am still using this display, I hope to upgrade in 2011.

- Rich
post #1246 of 1569
Below is my speculation:

I posted earlier that the patent literature suggests that adjusting initialization (both floating and rising blacks) prevents the need to raise scan (address) voltage or width.

There is a voltage drop issue at high APL due to impedence and there is also a change in materials (MgO) with increased usage time. Both these issues cause the pixels to misfire because the voltage required for discharge is raised relative to the applied scan (address) voltage. This is due to a lack of priming electrons.

So we can then break it down into the following cases:
  • If nothing is adjusted the pixels will misfire at high APL (due to voltage drop) and also misfire after the panel ages (due to MgO sputtering).
  • If scan(address) voltage is adjusted to compensate then no misfiring will happen but power consumption will change (higher power for higher voltages).
  • If scan(address) pulse width is adjusted to compensate then no misfiring will happen but too much time is consumed (less time to emit light as scan pulse width is lengthened). Efficiency is reduced.
  • If initialization voltage is adjusted to compensate then no misfiring will happen but black level will change (higher black for higher voltages). Power is not increased.

On top of that, a smaller pixel will exaggerate the stability problem as the voltage required for discharge goes up as the pixel becomes smaller. Panasonic moved to 1080p in 2007 as you mentioned and floating blacks became prominent (coincidence?).

Also, the luminance decreases with smaller pixels and to compensate more Xenon gas is used which has the drawback of requiring more voltage to discharge which again decreases stability. Part of NeoPDP is higher Xenon Gas Pressures (2009 as you mention) and again floating blacks became prominent (coincidence?).

Quote:
Originally Posted by Panasonic patent app#20090303222 View Post

In recent years, however, there is an expectation of further improvement in image display quality of plasma display devices along with their increasing definition and screen size. One of the approaches to improve image display quality is to increase the luminance. The luminance can be effectively increased by increasing the xenon partial pressure. This, however, requires a higher voltage for an address operation and makes the operation unstable................., in order to achieve a stable address operation, it is necessary to increase the address pulse voltage

Now here is the kicker. AFAIK, all of the issues with stability could have been solved by incresing the initialization pulse number or voltage high enough (increasing the black level). This would keep the discharge start voltage low even at high APL, increased usage time, and smaller pixels, and higher Xenon Gas content.

But Panasonic wanted to maintain highest contrast at low APL and at time zero so they chose to dynamically adjust the initiallization instead (dynamic black level - with time and APL)

Hence rising blacks and floating blacks.

But the question still remains. Even before power was important (pre - 2007 I guess). Why did Panasonic choose to mess with initialization rather than just adjust scan voltages??? Unless power has always been a concern? Even so I don't recall Panasonic designs being Power savers over the competition pre 2009?

Any ideas?
post #1247 of 1569
xrox,

Hmmm. Except my 2007 px75u had a 768 line screen and the floating blacks were very annoying -- in any picture mode other than Cinema that is.

I wonder if there is also a signal processing aspect to this phenomenon?

Larry
post #1248 of 1569
Actually I thought of a good possible reason:

Other manufacturers may have needed both high black levels and scan pulse adjustments to maintain stability.

Early Panasonic probably did as well but patented dynamic initialization adjustment to generate class leading black levels (only at low APL ) while maintaining stability at high APL. Scan pulse was still adjusted for usage time (hence no rising blacks yet)

Newer Panasonic designs required higher efficiency and with the black crystal layer (more priming electrons) they were able to eliminate the scan pulse adjustments for both high APL and usage time and only use the dynamic initialization adjustment to maintain stability. This increased efficiency without impacting stability but introduced rising blacks in addition to the floating blacks.

Any other ideas?
post #1249 of 1569
Quote:
Originally Posted by LarryInRI View Post

xrox,

Hmmm. Except my 2007 px75u had a 768 line screen and the floating blacks were very annoying -- in any picture mode other than Cinema that is.

I wonder if there is also a signal processing aspect to this phenomenon?

Larry

What about the measured black level. Was it lower than previous years?
post #1250 of 1569
Quote:
Originally Posted by xrox View Post

What about the measured black level. Was it lower than previous years?


xrox,

I've posted this before in the rising black level thread but I'm sure that it has long been masked by the noise over there.

My px60u measured about 0.033 ftL
My px75u measured about 0.024 ftL
Both my px80u's measured about 0.016 ftL

The readings did not seem to change over the year I had each of them. But I didn't take the initial reading until at least 200-500 hours. The 2008 px80u's were carefully measured with a i1LT meter over the 1500 hours of use that I had the sets.


Both my 2009 X1s started out at about 0.014 ftL and now they both are at about 0.022 ftL. These measurements were taken from about 200 hours to 5000 hours of use. The instrument used was my i1 LT profiled with my certified i1 Pro.

These are all 768 line models by the way. And all readings taken in the Cinema mode.

Larry
post #1251 of 1569
Thanks Larry,

And you only noticed FB on the px75? Or was it just more severe with the px75?
post #1252 of 1569
The floating blacks wouldn't be so bad if they happened more instantaneously. For example, when a scene changes, it takes a bout a second for the brightness to shift. If it happened at the exact same time that the scene changed, it wouldn't be so bothersome. Of course, we'd still have the problem in scenes where the shot doesn't change altogether, but the camera pans to a darker area of the room.

I'm wondering if the floating blacks occur more instantaneously on the VTs since CNET confirmed seeing the float on the S and G series, but not the VT (although many people here have claimed to have seen it on the VT as well).
post #1253 of 1569
One thing I found interesting (though frustrating too) that the Panny CSR noted was using Vivid to combat this. I immediately thought of how only Vivid turned the panel off (Infinite Black) on my G10 on an all black screen but no other mode would. So it makes me think that they are doing some different things driving the panel in Vivid mode only?

It is possible they are right in the Energy Star 4.0 compliance in the sense that they would use the dim Standard setting on the G20 to get the rating which may be helped further when the blacks float down on darker content. The side effect of this could be it affects all other viewing modes except for Vivid? I may try Vivid to see if they were blowing smoke up my behind.
post #1254 of 1569
RichB do you remember what values in the service menu were adjusted?
post #1255 of 1569
More patent evidence

Issued Panasonic patents 7446734 and 7583240 describe floating blacks in a 600Hz system using up to 5 black level shifts depending on APL.

Remember that the initialization step produces black level. More initialization the higher the black level. And APL can be thought of as % of the screen at full white. Check this out:






Reasoning (pay attention to bolded areas)
Quote:
Originally Posted by Selected paragraphs from Panasonic patents 744673 and 7583240 View Post


As described above, in this exemplary embodiment, because it is considered that there is no or a small area displaying a black picture when an image having a large APL is displayed, the number of all-cell initializing operations and thus priming are increased to stabilize discharge. In contrast, when an image having a low APL is displayed, it is considered that there is a large area displaying a black picture. Thus, the number of all-cell initializing operations and the black picture level are reduced to improve black display quality. Therefore, at a low APL, luminance in the area displaying a black picture is low, and an image having high contrast can be displayed even when the image has areas having high luminance.

In the all-cell initializing operation, it is necessary to cause initializing discharge using the scan electrodes as anodes and the sustain electrodes and data electrodes as cathodes. However, phosphors having smaller electron emission factors that are applied to the data electrodes may increase discharge delay in the initializing discharge using the data electrodes as cathodes, thus causing unstable initializing discharge in some cases.

Additionally, considerations are given to increasing the partial pressure of xenon in the discharge gas filled into the panel to improve the luminous efficiency of the panel. However, an increase in the partial pressure of xenon destabilizes discharge, especially initializing discharge. This unstable discharge poses a problem of writing failure in the subsequent writing period that is caused by a narrower margin of the driving voltage in the wiring operation.

With recent higher definition of a panel, the number of discharge cells is increasing and the period of time used for writing operation of one discharge cell is reducing. In addition, to improve image display quality, such as improvement of dynamic false contour, writing operation at higher speeds, such as discussion on a driving method for increasing the number of sub-fields, is required.

Now, the all-cell initializing operation for initializing all the discharge cells serves to form wall discharge necessary for writing operation, as described above. The all-cell initializing operation also serves to generate priming (priming=excited particles) to reduce discharge delay and stabilize writing discharge. Therefore, for stable high-speed writing operation, a method of increasing priming is effective. However, simply increasing the number of the all-cell initializing operations increases black picture level and decreases contrast, thus deteriorating image display quality.
post #1256 of 1569
Quote:
Originally Posted by Daravon View Post

Inspiring. I currently have a Samsung 50C550 that I bought because my S2 had bad floating blacks. It doesn't have exceptionally deep black level. I'm half-tempted to take it back and try a G25 with the LED trick. A panasonic with fully-floated blacks might have a comparable black level to my Samsung C500, and I feel that just about everything else about the Panasonics is better than my Samsung. Colors are better, IR is better, and quietness is better with Panasonics. Is there any way you can measure your LED-modded Panasonic so that I can compare it with Samsung black levels? Does anyone else have any input on which would have a better black level--a fully-floated Panasonic versus Samsung 50C550?

I tried taking a few photos with the LED on and then off... I could visually see the difference.. but my camera could not pick up the difference in black level en on a tripod with a fixed exposure and consistent lighting.

I suspect mine is not quite as dark as it once was since it's almost 9 months old now. Maybe the black level has risen slightly? Basically, the black level does not change that much in my opinion with the LED trick. The LED just keeps it from flickering up and down.... which is what people notice.
post #1257 of 1569
Quote:
Originally Posted by NoLows121780 View Post

RichB do you remember what values in the service menu were adjusted?

Yes, but it was given to me confidentially so I will abide by that.
I seriously doubt that these hexadecimal locations and values would be applicable to any other/newer panel.

- Rich
post #1258 of 1569
Quote:
Originally Posted by xrox View Post

Thanks Larry,

And you only noticed FB on the px75? Or was it just more severe with the px75?


It's the reoccurrence of the floating black issue that kept me from getting a 2010 model.


I don't remember much detail about the px60u. Although its blacks floated it was not as annoying as the px75u.

The floating blacks were there in the px80u but at a much, much lower level. The Cinema mode was quite solid though.

The x1 has even less than the px80u but, again, not at all noticeable in the Cinema mode. I can see some floating in the Standard mode but, once more, not as bad as the px75u.

From what I've seen in the 2010 models, each picture mode has quite different levels of floating. Standard and Custom modes seem to be the worst and it is always less in the Cinema or THX modes.


Oh, yes there is one more aspect: The time constant of the float seems greater in the 2010 models than in the px75u and all the other models that I've had.


Larry
post #1259 of 1569
My G20 seems to float the same regardless of picture mode or settings for that matter. I don't think it matters what settings are used on the 2010 G's. I can't speak for any other models though.
post #1260 of 1569
Quote:
Originally Posted by Camster View Post

My G20 seems to float the same regardless of picture mode or settings for that matter. I don't think it matters what settings are used on the 2010 G's. I can't speak for any other models though.

Same for the VT25, all you can do is vary how obvious or pronounced it is but it will occur no matter what tweaking you do with the Settings.
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