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I am helping my friend's purchase of 55" LED TV. He likes samsung and sony. It seems Samsung has 6,7,8 series LED TVs. which series has local dimming with good calibration options with grey scale and CMS ? Any specific model numbers ?
 

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Quote:
Originally Posted by photocrazy
I am helping my friend's purchase of 55" LED TV. He likes samsung and sony. It seems Samsung has 6,7,8 series LED TVs. which series has local dimming with good calibration options with grey scale and CMS ? Any specific model numbers ?
No Samsung 2011 model has local dimming currently.


Sony has 2011 local dimming with model HX929.
 

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Quote:
Originally Posted by Granzon /forum/post/20764548


No Samsung 2011 model has local dimming currently.


Sony has 2011 local dimming with model HX929.

false; the D8000 does (called micro dimming plus)
 

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Quote:
Originally Posted by PlasmaPZ80U /forum/post/20765048


false; the D8000 does (called micro dimming plus)

I suppose that depends on what you consider local. All of the Samsungs this year are edge-lit, but some of them have a local dimming feature (as best as a local dimming feature can be implemented from the edge). The Sony HX929 is a full-array with local dimming, as does the much cheaper Vizio XVT series.


It seems as though LG will be releasing some full-array, local dimming sets in the next couple of months.
 

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Quote:
Originally Posted by PlasmaPZ80U /forum/post/20765048


false; the D8000 does (called micro dimming plus)

It certainly would not meet the definition of true backlit Local Dimming - I don't know that anyone that would agree with you on that as it has no real zones that cover the panel.



Sony HX929, Vizio/LG Model, New Sharp XF5 60"/70" (Debuts 8/4/2011) are the real deal.



Here's a UK review that confirms the Samsung D8000 "Samsung D8000 3D LED TV Is Edge-Lit But Mimics Local-Dimming Backlight"


http://www.hdtvtest.co.uk/news/samsu...0110108982.htm
 

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Cnet can call it monkey intestines with diverticulitis if it wants, but it still isn't local dimming. You can't locally dim 2 dimensional space from one dimension, no matter how much Samsung would like to insinuate you can.


They artfully call it precision dimming, instead of local dimming because it sure is not the latter.
 

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It's not edge lit from the top, bottom and sides. It's only edge lit from the sides with really long light guides to make the middle bright enough (on most models). And it's only edge lit on the top/bottom on the 65" (and presumably the 75"??).


Unless someone designed a pretty radical light guide, I don't believe you could edge light from both the sides and the top/bottom at the same time. And if you could, I doubt you could get the kind of uniformity that would make dimming all that interesting.


Even if you could overcome the engineering challenging, it's fundamentally impossible to zone dim a screen lighting it from the edges and here is why. Say you want to dim the following coordinate x = 3 and y = 4 on a locally dimmed TV that had x = 16, y = 9 LEDs. You simply lower the lighting on the LED at 3, 4 and you've only affected that zone.


On an edge lit set, you could modulate the LED at x =3 and y =4 but that would affect 3,0; 3,1; 3,2 .... 3,9 as well as 0,4; 1,4; 2;4 ... 16, 4. There is no way around this problem as the same LED(s) have to illuminate the path down the entirety of the light guide horizontally or vertically. The problem might only be "half" this severe in that I suspect nearly all of the light is gone by the time you reach the middle of the TV and the other side takes over, but it's just not possible to use a passive light guide to dim a single x,y area from the edge of the screen.
 

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Then why does the link I provided for the LG edge lit local dimming models for example that there are eightedge lit row groups and 2 edge lit columnroups allowing them to have 16 edge lit local dimming zones,

I certainly agree that the result would not be that equal. I disagree with your engineering anallyis of how edge lit local dimming is actually implemented.

Any other inputs from those of you who design and/or implement edge lit local diming models would be appreciated.
 

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Quote:
Originally Posted by walford; /forum/post/0


I thought that the edge lit local dimming wetw applied edgelit backlighting from both the sides and the top/bottom in order to apply it from two dimensions.


See the following post

http://www.avsforum.com/avs-vb/showt...3#post20763303

Most Edge-Lits have left/right side dimming, the samsung Edge-Lit local Dimmer has top/bottom dimming.
 

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Do you disagaree that he link I provided for some LD edge lit local diming models the number of rows groups(lit from the side) and the number of columngroups (lit from the top or bottom) used to calculate the number of local diming zones?
 

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Quote:
Originally Posted by walford /forum/post/20769120


Do you disagaree that he link I provided for some LD edge lit local diming models the number of rows groups(lit from the side) and the number of columngroups (lit from the top or bottom) used to calculate the number of local diming zones?

I do not know the details of the edgelite with local dimming LED arrangement, but the following is not impossible.


First, light guides are thinner than placing LED right behind the LCD panel. So, the light source is placed on the edges (left right, or top bottom). On larger panels, top bottom make more sense, because we can then have more LEDs and shorter distance for the light guides. So far so good.


Second, is there a rigid rule that edgelit panels can have only one row of LED on each side? Can a second (or even more) rows be placed adjacent to the first row? Can some of the LEDs with dedicated light guides use solely for a certain "local areas"? If this is possible, then I will tend to believe that local edgelit can have local dimming as well. It will certainly not having as many zones as a full area backlit, of course.


If the number of zones are small enough, some sort of iris control of the light guides can also be used to dim.
 

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Quote:
Originally Posted by walford; /forum/post/0


Do you disagaree that he link I provided for some LD edge lit local diming models the number of rows groups(lit from the side) and the number of columngroups (lit from the top or bottom) used to calculate the number of local diming zones?

Seems that the info comes from LG directly (baidu.com link http://wenku.baidu.com/view/748eda12...9171128b5.html )



made a mistake, CNET Quote:'' the (und8000) LEDs have been moved from the top and bottom to the sides, which should help horizontal black letterbox bars appear darker.'' http://news.cnet.com/8301-17938_105-20043742-1.html .


The top/bottom comment seems a bit strange since in another CNET link they tell that in general Edge-Lit has leds all around the picture screen http://cnettv.cnet.com/cnet-faq-led-...-50094511.html .
 

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Quote:
Originally Posted by 8mile13;20769659

The top/bottom comment seems a bit strange since in another CNET link they tell that in general Edge-Lit has leds [U
/forum/post/0


all around the picture screen[/u] http://cnettv.cnet.com/cnet-faq-led-...-50094511.html .

I totaqlly agree that in order to provide decent edgel lit local diming that Leds would exist all around the picture screen.
 

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Quote:
Originally Posted by walford /forum/post/20770314


I totaqlly agree that in order to provide decent edgel lit local diming that Leds would exist all around the picture screen.

I have reservation on the necessity of LED all around the panel to enable local dimming. Don't get confused with regular retengular coordination. It still doesn't apply.
 

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Quote:
Originally Posted by rogo /forum/post/20767322


Even if you could overcome the engineering challenging, it's fundamentally impossible to zone dim a screen lighting it from the edges and here is why. Say you want to dim the following coordinate x = 3 and y = 4 on a locally dimmed TV that had x = 16, y = 9 LEDs. You simply lower the lighting on the LED at 3, 4 and you've only affected that zone.


On an edge lit set, you could modulate the LED at x =3 and y =4 but that would affect 3,0; 3,1; 3,2 .... 3,9 as well as 0,4; 1,4; 2;4 ... 16, 4. There is no way around this problem as the same LED(s) have to illuminate the path down the entirety of the light guide horizontally or vertically. The problem might only be "half" this severe in that I suspect nearly all of the light is gone by the time you reach the middle of the TV and the other side takes over, but it's just not possible to use a passive light guide to dim a single x,y area from the edge of the screen.

Hmm, how about using fast strobing principle so only a single zone is illuminated in every row/column at a time, other zones are darkened?


Samsung seems to use some clever technique in its dimming, on the original pic illustrating it there is also some kind of local contrast enhancement.
 

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Quote:
Originally Posted by irkuck /forum/post/20770632


Hmm, how about using fast strobing principle so only a single zone is illuminated in every row/column at a time, other zones are darkened?


Samsung seems to use some clever technique in its dimming, on the original pic illustrating it there is also some kind of local contrast enhancement.

Irkuck, like a sequential strobing of the backlight? It's interesting. The problem remains that along the illuminated light guide, there will be light... If you are "4 zones in", you will get light" no matter what you do.


I watched the guys rip apart the D8000 and while it's a marvel of engineering, there is nothing along each path that can mitigate this problem. If you want to brighten say, 3,4, you will brighten 0,4, 1,4, 2,4 and 4,4, 5,4... etc. You can certainly play some nifty tricks with the other "stripes" of the display to darken them.


I'm not sure how you can darken a single x,y with a light source only along the x axis no matter however. Perhaps you can further "illuminate" what you are suggesting.
 

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Quote:
Originally Posted by irkuck /forum/post/20770632


Hmm, how about using fast strobing principle so only a single zone is illuminated in every row/column at a time, other zones are darkened?


Samsung seems to use some clever technique in its dimming, on the original pic illustrating it there is also some kind of local contrast enhancement.

Your statement leaded me to think of CRT scanning. However, it seems quite different here. If all the lights diffuse evenly across the panel, then strobing won't achieve the local dimming effect. If as I said, some LEDs are supplementally dedicated to specific zones, then there is no need to strobe.
 
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