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Discussion Starter · #1 ·
Just learned from a Dutch (small scale) research that a heated room and (!) heated glasses can help a lot with crosstalk on LCD (LED?) televisions: Genieten van 3DTV? Zet de verwarming hoger! (article, like the title, in Dutch
). Differences are quite noticable between say 18 degrees and 24 degrees Celsius.


They advice to either raise the temperature of your room to something like 24 degrees Celsius or switch on the television for at least 15 minutes. The biggest gain for most people however will come if you warm up your glasses somewhat, which you could do for instance by placing them in front of a radiator (placed at a safe distance!). The higher temperature helps speed up the switching of LCD.


ps: Anyone got a link to similar results in an English article?
 

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Quote:
Originally Posted by Ettepet /forum/post/19580565


Just learned from a Dutch (small scale) research that a heated room and (!) heated glasses can help a lot with crosstalk on LCD (LED?) televisions: Genieten van 3DTV? Zet de verwarming hoger! (article, like the title, in Dutch
). Differences are quite noticable between say 18 degrees and 24 degrees Celsius.


They advice to either raise the temperature of your room to something like 24 degrees Celsius or switch on the television for at least 15 minutes. The biggest gain for most people however will come if you warm up your glasses somewhat, which you could do for instance by placing them in front of a radiator (placed at a safe distance!). The higher temperature helps speed up the switching of LCD.


ps: Anyone got a link to similar results in an English article?

It is not the LC shutter glasses but the monitor which generates ghosting.

As the acronym says Liquid Cristal Display the liquid's viscosity changes with temperature and the crystals are able to rotate faster thus shortening the refresh time.


Mathew Orman
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by icester /forum/post/19580838


It is not the LC shutter glasses but the monitor which generates ghosting.

As the acronym says Liquid Cristal Display the liquid's viscosity changes with temperature and the crystals are able to rotate faster thus shortening the refresh time.

Yes, but the people who conducted the experiment found that warmer (and therefore faster switching) LCD shutter glasses help reduce crosstalk in their setup. From what I gathered they tried this with several LCD/LED televisions. At no time did I use the word 'ghosting'.
 

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Quote:
Originally Posted by Ettepet /forum/post/19580866


Yes, but the people who conducted the experiment found that warmer (and therefore faster switching) LCD shutter glasses help reduce crosstalk in their setup. From what I gathered they tried this with several LCD/LED televisions. At no time did I use the word 'ghosting'.

So,


what is crass talk in your opinion?


Mathew Orman
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by icester /forum/post/19580905


So,


what is crass talk in your opinion?

You get crosstalk with 3D shutter glasses when they don't switch fast enough to fully block the image meant for the other eye.



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Edit: To clarify "Ghosting" (with 3D shutter technology) means the display leaves part of the image visible after it was shown to the other/"previous" eye. It is visible mixed through the current image and will prove difficult/impossible to completely filter out. Of course if you look at the "blanking" period between left/right frames you will get a mix of crosstalk and ghosting with current slow switching shutter glasses & displays.
 

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Slow response by either or both liquid crystal shutter glasses and displays when cold could certainly result in crosstalk. For the glasses if the open LC shutter takes too long to become opaque then it will pass some of the next (i.e., wrong) squentially displayed image rather than fully blocking it. For displays if the reponse time is too slow because of a cold display there will be a longer period when the previous image is still slowing fading away while the new image is slowing appearing.
 

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Quote:
Originally Posted by Ettepet /forum/post/19580959


You get crosstalk with 3D shutter glasses when they don't switch fast enough to fully block the image meant for the other eye.



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Edit: To clarify "Ghosting" (with 3D shutter technology) means the display leaves part of the image visible after it was shown to the other/"previous" eye. It is visible mixed through the current image and will prove difficult/impossible to completely filter out. Of course if you look at the "blanking" period between left/right frames you will get a mix of crosstalk and ghosting with current slow switching shutter glasses & displays.

Must be your own theories.

It is not possible for LCD display to show two images at the same time. LCD has no phosphor like CRT.


The only time glasses are at fault is when their control signals are out of sync or wrong duty cycle for ON and OFF states.


So ghosting and or cross-talk has the same meaning for LCD technology.

But people often mistake crass talk with excessive parallax when they see double objects not having able to fuse it or converge on it.


Mathew Orman
 

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Discussion Starter · #11 ·

Quote:
Originally Posted by knobby /forum/post/19581241


how long would it take in microwave?

These findings are just a first step! Further research is necessary how we can super heat the glasses, while still comfortable to wear...


Quote:
Originally Posted by icester /forum/post/19581789


Must be your own theories.

It is not possible for LCD display to show two images at the same time. LCD has no phosphor like CRT.


The only time glasses are at fault is when their control signals are out of sync or wrong duty cycle for ON and OFF states.


So ghosting and or cross-talk has the same meaning for LCD technology.

But people often mistake crass talk with excessive parallax when they see double objects not having able to fuse it or converge on it.

It is fairly easy to reproduce (or refute) the influence of temperature on a few sets of 3D LCD shutter glasses. If you then want to proof that higher temperatures cause a better sync then go right ahead.
 

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Quote:
Originally Posted by Ettepet /forum/post/19582531


These findings are just a first step! Further research is necessary how we can super heat the glasses, while still comfortable to wear...




It is fairly easy to reproduce (or refute) the influence of temperature on a few sets of 3D LCD shutter glasses. If you then want to proof that higher temperatures cause a better sync then go right ahead.

Changing subject?

You claim that it is possible for LCD to display a ghost of previous picture.



I have already stated that increasing LCD operating temperature reduces the viscosity of liquid thus shortening physical refresh cycle or speed of crystal recombination. It also means that if there is ghosting, it is also reduced with temperature increase.


Mathew Orman
 

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Discussion Starter · #13 ·

Quote:
Originally Posted by icester /forum/post/19582632


Changing subject?

You claim that it is possible for LCD to display a ghost of previous picture.

No and no.


My earlier explanation was pretty clear, or at least clear enough to show I didn't claim anything of the sort.


I would think the thing to do right now is check the influence of this seemingly unexplored area of warm/cold 3D shutter glasses (which most of us have). I have greatly enjoyed reading your posts about the deeper workings and theories of 3D displays, movies, possibilities, limitations etc. I have great respect for highly knowledgeable and experienced people who share their insights with us mere mortals, like it seems you are doing.
But why battle against small incursions on what you consider right in stead of small corrections and hints of what you think is really going on?


I might be wrong but wouldn't it be much better for you to a degree aid in making a wonderfully detailed and informative FAQ here, and share knowledge wherever it is meaningful and in a way which is mutually rewarding?


Quote:
I have already stated that increasing LCD operating temperature reduces the viscosity of liquid thus shortening physical refresh cycle or speed of crystal recombination. It also means that if there is ghosting, it is also reduced with temperature increase.

And why wouldn't the same apply to LCD shutter glasses? If the LCD is too slow to make a full on/off cycle quickly enough then why couln't it show part of the previous or next image when these should be 100% blocked?
 

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Quote:
Originally Posted by Ettepet /forum/post/19582977


No and no.


My earlier explanation was pretty clear, or at least clear enough to show I didn't claim anything of the sort.


I would think the thing to do right now is check the influence of this seemingly unexplored area of warm/cold 3D shutter glasses (which most of us have). I have greatly enjoyed reading your posts about the deeper workings and theories of 3D displays, movies, possibilities, limitations etc. I have great respect for highly knowledgeable and experienced people who share their insights with us mere mortals, like it seems you are doing.
But why battle against small incursions on what you consider right in stead of small corrections and hints of what you think is really going on?


I might be wrong but wouldn't it be much better for you to a degree aid in making a wonderfully detailed and informative FAQ here, and share knowledge wherever it is meaningful and in a way which is mutually rewarding?




And why wouldn't the same apply to LCD shutter glasses? If the LCD is too slow to make a full on/off cycle quickly enough then why couln't it show part of the previous or next image when these should be 100% blocked?

Sorry,

you are right I should not have argued about irrelevant detail.


The reason I claim is not shutter glasses at fault is because there is a sufficient time for shutter ON/OFF switching action

even for the slowest shutter there is in current products.

I have worked with LC shutters since the first Sega TV LC shutters in 1985. It still have a pair and it works perfect up to 500 Hz.

The other reason is the actual switching time is so short and even if happen during refresh cycle it would only means less than 2% to 5% of ON duty cycle. Such short flash would not contribute to ghosting.


Finally in my opinion the best effective way to reduce ghosting on LCD monitor is to reduce the refresh cycle time.

Lighter crystals and liquid with less internal friction.

I bet LCD panel manufactures are working on it as we speak.

Every manufacturer wants to offer 3D monitor that is at least 120Hz capable and ghost free.



Mathew Orman
 

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Discussion Starter · #15 ·
Thanks for that.



So you have no idea how or why these people claim to get better performance out of LCD glasses which are slightly above room temperature when compared to those a few degrees below it?
 

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Quote:
Originally Posted by Ettepet /forum/post/19583282


Thanks for that.



So you have no idea how or why these people claim to get better performance out of LCD glasses which are slightly above room temperature when compared to those a few degrees below it?

Well, it is in Dutch.

So I do not know the details about the experiment.

One thing for sure TN cells do not operate well in low temperature.

If for example in the experiment they would have ghosting at 20 deg Cecilius and only changed the glasses temperature observing reduction in ghosting then that would suggest to me that there is something wrong with

the LC shutter driving circuitry which alters the timing.

Again without details I would not like to speculate much.


Main suggestion for them is to use DLP or Plasma when testing LC shutter glasses performance.


Mathew Orman
 

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Well I pauze my 3D movie at one moment where I noticed a lot of ghosting on a particular point. That was my reference point.


The room temp was 20 degrees.


I heated up te glasses, but that didn't help.


Then I heated up the panel on my reference point with a blowdryer till it felt warm. So i think that would be around 25 degreed.


I was amazed to see that the ghosting at the reference point was completly gone !! wowww


So it does work.
 

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Discussion Starter · #19 ·
Warming up the screen does appear to help lots (as many knew already).


Proof of temperature influences on the performance of shutter glasses has yet to be replicated. Maybe problems with shutter glasses occur when they are relatively cold, way below 20 degrees Celcius. Have only tested heated glasses sofar, which didn't improve performance (much).
 

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Getting back to the original poster's comments, both the television screen and the shutter glasses rely on liquid crystal mechanisms, and both are subject to temperature effects (mobility of the liquid crystal alignment). Most shutter glasses shouldn't have problems since they are designed to have a window (transmission) time shorter than the image presentation time, but if the glasses are a marginal pair, being cold might inhibit a given (left or right) lens from darkening fast enough to block the opposite stereo image presented by the display, hence ghosting. It's the darkening time which contributes to ghosting since a given lens must reach an almost opaque state before the alternate image appears on the screen.


Likewise, the screen LCD system must blank a given image before the opposite lens in the glasses becomes transparent or there will be crosstalk between the stereo image pair. That's one reason plasma displays can achieve superior stereo performance - their blanking times are much faster than current LCD panels.


To make a long story short, warming LCDs will increase their switching speed and thus may reduce crosstalk if it's due to LCD lag. Moral: don't keep your 3D LCD system in a cold environment.
 
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