Possible Permanent Backlight Bleed Fix for LCD TVs and Monitors w/ disclaimer - Page 2

I'm going to have to agree. While this may have perceptively 'improved' the clouding for a couple members, this is not a good idea in any sense. You really are more likely to damage your LCD screen than help fix it. I would hate for someone to press their screen too much and damage it while trying to reduce clouding.

For those owners where this method helped, its possible your screen may be improved, but I highly doubt that this direct method was the cause. I'm glad your screen has shown improvement, and hopefully you are happy with your set. But screen uniformity simply can't be fixed by tapping or rubbing.

Finally got a chance to experiment - huge improvement! I used a small paint roller and gently rolled the entire screen, which, I assume, changes the spacing between the actual lcd panel and the plastic diffusion layers beneath. Completely viewable now. I am happy with the fix but it isn't for everyone or the faint of heart.

But I agree, this thread should be closed and/or removed. It will only go downhill from here. Too many people need to have the last word.

Here's the thing: There are no diffusion layers between the part you see and the screen. You either see (a) the panel itself or (b) an external layer in the rare TVs where one is added (Sony HX929 has the Gorilla Glass front, for example, with a layer behind that and only then the panel... This construction is fairly rare.)

The "diffusion layers", the brightness enhancement films, etc. are located behind the panel, not in front of it.

Light leakage is a function of the edge LEDs not fully feeding light into the light guides on the edge of the TV and/or feeding the light in at an imperfect angle. When you see flashlighting occurring at the very edge of the screen, it's almost certainly that the edge LEDs are pointing ever so slightly toward the front of the panel such that some of the light never enters the light guides. When you see "clouding" it's a similar, but less extreme alignment flaw. I suspect the flaw can also occur when the angle is "backwards", pointing too far to the rear, but that would be unlikely to manifest itself as flashlighting, although could certainly cause "clouding".

The only reason this fix has any chance of working at all is that you might -- almost by accident -- push things into alignment when pressing on them. To do this, however, you are exerting pressure on the panel itself, which is playing no role in your problem. It's kind of like banging on the engine to get something loose in the transmission to move back into place.

The panel is the expensive, un-repairable piece of your TV. Why people would risk damage to the panel to attempt this "fix" is beyond me. It's crazy.

I don't think that you managed to move the diffuser + BEF's; you have probably just introduced mechanical stress to the way pixels rotate to let through the light -> like hydraulic valve turns to control the fluid flow. You may have equalised the stress across the whole LCD panel - removed any bias that was there due to incorrect assembly, or bad shipment / transport…..

Diffuser is further back, BEF’s are immediately behind the LCD panel. BEF’s (brightness enhancing film sheets) are also known as lens sheets. The light-manipulation “sandwich” consists of 1 thick diffuser, and 1 or 2 thinner BEF’s. Diffuser is there to disperse the light evenly across its whole area. BEF’s have 2 basic functions:
1: to refract the photons multiple times until they are angled correctly to pass through the LCD panel at right angle – “straight through”. This technic optimises brightness and contrast AND, unfortunately, is the main reason why the viewing angles suffer. Many people believe that the viewing angles are purely the function of the LCD panel type used… this is wrong! If 1 BEF is used -> manufacturer can choose if horizontal OR vertical viewing angles will be affected (of course, vertical viewing angles are less noticeable...) If 2 BEF’s are used -> both viewing angle planes are affected equally.
2: to direct the photos (that can not be angled correctly) back towards the backlight source where they are virtually re-bounced of the white plastic reflector -> re-used and re-attempted at getting them to the right angle to pass through the LCD panel. This technique can save up to 30% in backlight photon generation costs – read: electricity.

The whole sandwich has to be assembled loose and be able to move freely between LCD panel and the backlight source; however, it has to be firmly AND correctly placed to REST on the bottom plastic holders, so that the “sandwich” does not get stuck between LCD panel and the TV metal frame during assembly OR during transport.

The whole backlight generation and its manipulation is so “basic” and trivial… with so many areas where things could go wrong…. it is amazing how good the LCD TV picture actually is…. CRT TV technology is much more elegant, precise and sophisticated… with the way electron beam can be controlled (even speeded-up on large flat CRT screens to obtain same peripheral speed across full width of perfectly flat CRT screen with single point of beam generation).... but picture tube size have limits, and then there’s a vacuum, residual magnetism.... weight… bulkiness.

Boky

I just want to again clarify. "Diffuser" was a more appropriate term for CCFL based LCDs which used an array of fluorescent tubes positioned on a backplane behind the TV. Since the lamps were positioned behind the diffuser layer, the design was often quite simple.

Edge-lit LCDs -- the bulk of what's on the market today -- use a row of LEDs either on the right/left or top/bottom. For those to come remotely close to evenly illuminating the screen, a "light guide" is used in combination with a diffusing film layer.

There's a detailed paper here: http://www.ciri.org.nz/downloads/Lightpipe%20design.pdf

Unfortunately, it doesn't really cover what I'd call a modern edge-lit LCD TV. Page 9 here helps:

http://www.hitachi-displays-eu.com/d...cklighting.pdf

Another so-so reference here:

http://catalog.osram-os.com/media/_e...00016610_0.pdf

which described the light guide getting thicker far away from the light source.

This is what happens with two-sided edge-lit LCDs, the light guides are thin nearest the LEDs and then thicker toward the center. The purpose of this is to attempt to create even illumination across the display (note, I do believe most LED-based LCDs use a light guide + diffusing film + brightness enhancing film(s), but designs doubtless vary).

The imperfection of the light guide designs is one issue, but the need to perfect the light entry into the light guides (to avoid flashlighting) and to perfect the incident angle to allow for even illumination rather than "clouding" is not easy, especially when you consider the guides themselves are plastic and made to imperfect tolerances to begin with. Add in the issue of maintaining the proper spacing and you can see where things go wrong.

Again, though, whatever you do on the front of the screen is operating at this from the wrong end and risks damaging the panel, which is playing virtually no role in your problems.

I just bought a Samsung 55 led tv and it has this flashlight affect in every corner and also some clouding issues. I have tried this massaging technique and it does seem to work some. At least its a lot better than it was but its not perfect. I have 30 days to return the TV so I will keep giving this a try and if doesn't improve more, or I break it, then I will just return it.

shameful

^^^^^ agreed

Really really stupid things:

1) "Massaging" your LCD screen thinking this will repair it.

2) Breaking a TV while doing #1.

This technique is ridiculous. It's like dunking suspected witches and proving the ones that drowned weren't witches.

Samsung displays have terrible uniformity. This is well known. You aren't going to fix this by rubbing your display. And for the umpteenth time: Uniformity problems are caused by issues regarding the light guides and LED modules. The part of the TV you are rubbing is the actual LCD display which in no way is contributing to your uniformity problems.

If you went to the doctor and told him you had back pain and he said, "hey, no problem, we'll put you on dialysis", you'd think he was insane. Rubbing the LCD panel to fix a problem with the light guides and the LED modules is reasonably close to the same thing.

The reason for the light spots on the darkness of displays has nothing to do with backlight bleeding. More so your LED / LCD digitizers (display) is under pressure at certain points particularly the corners where the screws are drawing it back.

This is the reason the spots appear at the corners in particular and edges of your screen. Loosen the screws and tug on the LED display easily (not hard) and step back and notice all the light spots are 90% - 100% better.

The screws are too tight. Massaging and tapping the screen is completely ridiculous. Since i have offered the only solution that works, i appreciate it if you remember i took the time to tell everyone that encounters this issue.


Good luck.

I had a solution to this problem this weekend. My new Vizio M3D550SR had some pretty serious corner flashlighting and some bleed along the bottom edge. I noticed if you put slight pressure along the edges of the screen the light bleed would shift and disappear. I ended up cutting up some small slivers of a credit card to use as shims. Sliding these between the frame and screen at certain key prssure points along the edge of the screen almost completely eliminated the problem. I was planning on returning the set as it was pretty distracting, but now even in a totally dark room it looks pretty good. Probably not the ideal situation, but it worked.

I've been reading about this fix (redo the screws in the back) for about 5 years now, so it's not new fix. Even with the engine heads made from metal you need to follow certain procedure during assembly to avoid head warping.
It is much easier to warp the panel assembly made from plastic. I would speculate that massaging the screen pushes the panel just enough to get rid of some bending introduced during assembly and reduce the light bleed, that's why some members claimed it help them. But I also agree it's not very safe way of doing this and if you have the problem, proper way would be loosen all screws in the back and properly re-tighten them, if you don't want to return the set.

Well thanks for taking the time...that solution has been discussed a couple of hundred times over the last few years but we will do our best to make sure you get a mention.

So just to be clear, when the edge lights are in fact shining through from the bezel, that's our imagination, right, not backlight bleed? I'll be sure to tell everyone you were responsible to explaining to me why my common sense was completely invalid. Thanks!

What he is probably trying to say is, that during assembly process excessive or uneven torque applied to screws, warps the screen and causes excessive light bleeding on some sets. I have no excessive light bleeding in the corners on my set, but I believe some people have it and I also believe in some cases this could be fixed by relieving some of the stress on the panel by following above. Now if your common sense allows you to believe that or not that's another story altogether.

will this void the warranty, also how many turns 1/4?

I had quite a bit of clouding but i just noticed tonight that it is a lot better. The tv has been on most of the day so i will try it tomorrow morning when the screen is cold. But now all i have to fix is the flashlighting

if you could manage messing something up - probably it would void warranty, but probably it's safer than let's say moving the set from one place to another.
I'm sure some "talented" person could find the way to mess simplest of tasks. Also if there are tamper proof paint markings on the screw or some type of seals, to discourage opening the set I wouldn't touch that either. Since the assumption is during assembly the force of the screws somehow warped the panel, you would probably want to loosen them all and re do them by hand, not too tight or too loose, in some type of cross pattern.
Of course if the assumption was right and that's not given at all.

I just bought my first Samsung LED and the flashlight corners (all of them) and clouding spots all in the middle are driving me nuts. Some folks don't care about these things, but I think I am going to bring it back and find a plasma (I do). I thought by waiting 2-3 years that they would have worked these bugs out. I wanted to wait until the OLED's come out cheaper, but I cant keep fixing my XBR800.

Viewing angles are also poor and the image gets more washed out as you move away to the sides. You have to be right in front of it...bummer. Other than these items, it looks great.....but I sure miss my HD CRT.

Hello there,

Just wanted to give a bit of insight into this matter. First off, I am far from being a newbie and I have been building my ever evolving piece of video game heaven for around 10 years. I have 2 55" LG 3D Edge Lit LED TV's at the moment, one is the 55LW5600 and the other is the 55LM7600. I built my system so that any component can be easily changed out as the technology improves, my TV is no exception. I recently bought a newer TV but unfortunately did not get a chance to really put it through the paces over the holidays. Just recently I started playing games again and much to my dismay, I am plagued by one very noticeable hot spot in the lower right corner... I am a RewardZone Silver member, so I have 45 days to return items purchased at BestBuy. Too bad I did not notice this until after it was too late to return it. I normally inspect every aspect of any piece of electronics I buy (and return it for almost any imperfection if I find one) but the screen was perfect, so I set everything up and went back to rushing around getting ready for Christmas.

I do suffer from extreme OCD, especially when it comes to electronics and would have never considered something as silly as applying pressure to my beloved screen... In fact, it is heresy to touch any display that is not a touch screen in my house. I am experienced at fixing various components and have fixed several TV's, including my 56" Samsung DLP from two systems ago that still works to this day.

Now that you have a bit of back story, I am here to tell you that if this is done properly it actually works great!!! I did use a microfiber cloth and tried to apply the pressure gently and evenly, covering as much area as possible rather than applying pressure to a small area. I wrapped my fingers around the back of the set and used my palm to do the dirty work. I also tapped gently with the microfiber cloth covering my finger. Basically, the pressure pushes the uneven section of the light source out toward the edge where it belongs.

I know the experts say not to do this and to remove the thread, and normally I would agree with them if I did not see it work first hand. I did not damage my set at all and do recommend performing this operation with the utmost caution and a gentle touch. I am still kicking myself for not taking a before and after picture, but I can assure you all that it made a huge difference for me! I was so unbelievably disappointed because once I see something like that I obsess over it. Now I am actually enjoying my TV instead of obsessing over what I consider to be a very significant flaw.

Good luck and Godspeed!
Edited by Zomby - 1/20/13 at 12:19pm

One more thing:

While experimenting with different ways to apply pressure without causing damage I stumbled across a very effective technique. Try to wipe the screen in a circular motion, while gently pressing outward along the edge with a microfiber cloth using just slightly more pressure than you normally would to clean it. You can see the LED's changing color along the edge and the light source will guide you as you smooth it out. I actually worked along the entire edge of the TV and it seems to have made it more uniform all the way around. It does suck having to touch your screen in such a manner. I was haunted by memories of women in the office pressing on the computer screen with their fingernails or the tip of a pen. I used to cringe every time I saw the LED's turn white on the screen where they were pressing. This is almost as scary IMO but well worth it if your light bleeding is distracting enough. Anyway, use extreme caution and a microfiber cloth at all times if you dare to attempt this procedure!

Cheers!!!

Alright folks, here it is...

I have become fascinated with this because of how good it seems to work and took some before and after pics. There is beauty in simplicity!!!

Let us begin with the before:



As you can see, this was not as severe as the original spot that encouraged me to search for a solution, but the lighting still lacks uniformity along the upper edge...
Edited by Zomby - 1/15/13 at 2:18pm

This is the result after about 3 minutes of gently using the technique described in my post:



As you can clearly see, there is significantly more uniformity in the area in which I used this technique. It is not perfect mind you, but it has made such a drastic improvement to my viewing experience that I am a believer. As I stated earlier, it is heresy to touch a TV screen in my house. I don't like to touch them to clean, even with a microfiber cloth due to the chance of any contaminant trapped in the fibers that may damage your screen, which I have seen happen. Buy a Monster cleaning kit for acrylic screens and use the microfiber cloth that comes in there. It is the highest quality microfiber cloth I have found and is the only thing that is ever allowed to touch a TV screen in my home.

I did this only for a few minutes to demonstrate how effective the technique is. Gently rub in a circular motion outward along the uneven sections and work your way around the screen. If the spots are further from the edge, work them toward the edges in the same manner you would work an air bubble toward the edge of your screen protector on a touch screen if that makes sense. Please keep one thing in mind when attempting this procedure; your television screen is not meant to be touched unnecessarily, so proceed with the utmost caution and a VERY light touch. You do have to apply a small amount of pressure to achieve the results that I did, but I cannot stress to you enough that you must have patience. The longer you are willing to sit there and make things perfect, the better your results will be!

Again, good luck and Godspeed!!!
Edited by Zomby - 1/20/13 at 12:21pm

One more set of pics for you:



No, I did not mistakenly take pictures of a plasma screen!!!

Yes, the black levels and screen uniformity are pretty darn good!!!

No, this was a "legitimate" massage... but there is a happy ending!!!

And here we have an LG 55LM7600 3D 240hz Smart Edge Lit LED in three different lighting scenarios ranging from a pitch black room on the left, very low light in the middle, and slightly more light on the right. I have literally been working on it since my last post about an hour ago and the results speak for themselves! Has anyone ever seen an edge lit LED that looks this good with a black screen!?!? My camera isn't the best, but come on!!! In all fairness, this TV was much better than some of the pics I have seen in the forums of edge lit LED's, but after using this technique this one is about as uniform as anyone could hope for. I would have never expected such a great result from such a simple idea! And I most certainly would never have stumbled across this by accident since I really do avoid touching TV screens unless absolutely necessary...

Thanks for starting this thread!!!
Edited by Zomby - 1/16/13 at 9:24pm

Something helpful to consider:

"If anyone would like to try out some settings that may optimize color accuracy and black levels," go to http://www.flatpanelshd.com/ and look for the review of your set. If they did not review your exact model, find the closest one and use those settings. For example, the 55LW5600 I recently rotated out of the system was not reviewed, so I used the settings for the 55LW6500 and it looks great. It will make a drastic difference for you too. I have actually installed quite a few home theater systems for other people and it is a good tool, especially when you may not be familiar with the set you are installing. I also trust the reviews and use them when considering purchases quite frequently. We may not be able to get around all of the flaws inherent in the current technology, but you can maximize the performance of your system to help minimize their effect as much as possible.

Below are flatpanelhd's calibrated settings for the LG LM7600 as an example:

http://www.flatpanelshd.com/review.php?subaction=showfull&id=1333359799

Expert1 mode

Picture preset: Expert1
Backlight 47
Contrast 85
Brightness: 50
V/H Sharpness: 50
Tint 0
Dynamic Contrast Off
Super Resolution Off
Colour Gamut Standard
Edge enhancer Off
Color Filter Off
Noise reduction Off
Mpeg noise reduction Off
Black level Low
LED local dimming Off
TruMotion Off
Color temperature Warm
Gamma 2.2
RGB Method 2 point
R high -6
G high -11
B high 18
R low -1
G low -2
B low 4


Note: The Eco option is set to On/Off in the table because it depends on your preferences. Eco is the automatic brightness adjuster that adjusts brightness according to the surroundings. It is a practical setting if you watch TV during both daytime and nighttime but if you have a home cinema with controlled lighting, I suggest that you leave it off.
Also, the RGB high and low settings were switched around on our LM7600 sample. Check to see if they are on your TV as well.
Edited by Zomby - 1/30/13 at 12:35pm

Moderator

off topic DIY posts removed:

thread title edited to add: (not recommended by AVS)

Hi to all,

Yes, it may seem silly to try this method but it did work for me. I had backlight bleed in the centre of my screen and now it is gone. Now, it is important for me to state that I sent it in for repairs and it came back with absolutely no fix what so ever. I usually clean all my screens with microfibers when people touch my screen (some annoying people in my life) and I also just clean when there is dust.

I was about to pack the TV back up to send it back the next morning when I found this post. So I took a microfiber and ran my hard around the entire surface of the screen like I normally would when cleaning any other screen. I applied slight pressure (I've gone this before and never had an issue with other TV set) because they left smudges from my screen after the so called repair and when I was done the bleed was completely gone.

Some of you are talking about tapping the screen, I don't really recommend that. As I have said, my bleed was in the middle of my screen, maybe it doesn't work if it is in the corners but this solution definitely worked for me.

If you don't know what you are doing then don't bother doing this because before you know it you've cracked your screen.

Anyways, thanks for the tip, I saved my another repair trick and more scratches on my set.

updated thread title...thanks