Wednesday, January 10, 2007

What Is Mura??

Excerpts From This Article

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"Mura Effect type 1 corresponds to a lack of homogeneity in control circuit adjustments. From one cell to another color control can change and it will lead to permanent defects in intensity in displayed images.

Mura Effect type 2, or Cell Gap Mura comes in two forms. If liquid crystal cell sizes are superior to the normal size in an area of the panel, the images produced in this area will be brighter. This is a White Mura. In the opposite way, if the cell size is too small, it will be darker. This is a Black Mura. Cell distortions sometimes come from a « normal » defect in manufacturing, but most of the times are due to an impurity in the panel such as dust, a drop of some chemical or an accidental ionisation of liquid crystals, which then misalign. For the first two cases, it is possible to move the defect by gently pressing the panel with your fingers to move the Mura to the side from a useful area in the screen. In the case of ionisation, the defect can fade or even disappear with time. For us it was the opposite with the appearance of a Mura on two monitors after a few years of use (three and five years, respectively). It looks as if you were pushing on the screen with your fingers except now it´s permanent.

Mura Effect type 3 is related to distance or defects between the panel and liquid crystals. This occurs when the panel is sealed and side pressure is imperfect. If it´s too strong, cells are crushed and there is a bright halo in a corner along the panel."

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(Images taken from here)

Price-slashing could be a culprit in the Mura effect. Is Sony is cutting costs on the quality of the parts, on their flagship top-of-the-line LCD tv no less? It is outright unacceptable.

15 comments:

Anonymous said...

You shouldn't be cut-and-pasting images and content from copyrighted websites. Link to it, yes, but don't steal content. That's plagiarism and puts you on no higher moral ground than the company you are criticizing!

Anonymous said...

This is really interesting. Thanks for putting this in a blog. I don't understand why you would buy a TV that has white spots on the screen. If I saw that in the store, I wouldn't buy it. How can I tell if a Dell I am looking at will have white spots?

Bob in Atlanta

Anonymous said...

Bob - they didn't see it in the store when they bought it. They didn't see it until they got home, turned the backlight up to "torch mode", turned off the light sensor, eliminated ALL ambient room light (pitch black room), and then put on a blank input or source material that is unusually dark.

This is going to be a pretty funny "internet legend" about LCD displays. "Remember all those Sony XBR owners who didn't know how to ajust their display???"

LOL

Anonymous said...

You should really check out the threat on the AVS forum, maybe you would get a realistic idea of the magnatude of this problem. There is a wide variance in the degree of the problem based on the information posted there, but I seriously doubt that ALL those people are wrong when they report that they see it under viewing conditions that one might expect to encounter in the home (dark scenes viewed in a dark room, factory settings). I don't own a set but probably would if I didn't think there was a valid issue here. Why would Sony be working on a firmware "fix" if there isn't some validity to the claims? Some of us like to be informed before we make decision or spout an opinion.

Anonymous said...

Thank you so much for creating this blog. I just bought a KDL-32XBR4 yesterday night. After set up I noticed a light spots whenever the background went to black with a very noticeable one in the upper right corner. Beautiful picture when you are watching daylight scenes, but anything at night, dark room. outer space, etc- totally distracting.
After totally wasting 30 minutes with Sony on the phone ("Have you tried unplugging the TV?") I went searching online and found this blog.
Sony suggested I have the TV "serviced". I suggest they own up to the problem and make the product right. Tonight it's another trip to BestBuy for me.
-Mark in Chicago

BLACK SUN studio said...

well good to know that I am not the only one experiencing clouding issues on these fabulous Sony's. This wkend I picked up a brand new KDL40XBR4 in the box from BestBuy. This was to replace the one I bought a month ago that had clouding issues as described above (varying intensities of white clouding on the black screen across the screen, mostly in the upper corners). The guys at Best Buy were fantastic, which caught me by surprise. But much to my surprise, this new set had the same clouding issues and even worse! You don't see it if a bright colored image fills the entire screen, but you do see the clouding if the image displayed does not fill the screen i.e. 4:3 std tv or some wide screen movie formats. It is especially noticeable and distracting if watching a black/white movie. I thought I was being overly critical and unlike my character was going to settle, but no way. I have another 30 days on this set and will work with Sony and Best Buy for resolution of the problem.

Thanks for the Mura info, this will help in presenting the issue back to Best Buy and Sony.

Anonymous said...

Thanks for the info.

David said...

I have gone through 4 Samsung TV's (I understand Sony and Samsung are made by the same manufacturer). 3 of the 850 models and 1 650.
I called both Samsung AND Bestbuy where I bought them from and BOTH claimed never to have heard of the clouding that I was complaining about.
Bestbuy sent someone from their Geek Squad out and Samsung sent their own approved repair person out. Neither knew what I was talking about (nor did anyone from tech support) and said it will go away with calibration - which it didn't!
I will never buy Samsung or Sony again, because these people have to have heard of this before, which means they are not acknowledging they know.
I knew I couldn't be the only one and this blog confirms that.

Anonymous said...

I have had a SONY XBR5, three Samsung 630s, and a LG 42LG70. All of these tvs have had cloudy spots on them ('mura', 'bruising', 'blemishes', whatever), except one samsung that died out of the box. I have given up hope on getting an unflawed LCD and I am very, very, very disappointed in today's tv manufacturers. This has become an LCD nightmare for me and I am tired of fequenting futureshop for returns (I think that they are sick of me too). It's good to know that it is not just me that is having this problem, but at the same time, I feel your pain. Even when you take the tv out of the box in the store and carefully inspect it, there is still a possibility these marks will appear.

Unknown said...

Your post really cool and interesting. Thanks very much.

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Anonymous said...

I bought a sony klv32R412B.. The brand new one, when turned on, has a black spot/patch at the top end of the screen. I called sony, replacement agreed, done. This one now has cloud/mura effect when on no signal input! .. I Called sony and they say it's ok- won't be a problem. IT IS!!. I'm very disappointed.. The older CRT TVs are better than these latest ones. From pocket ones, 14, 21, 32 inch, i've used them all- sony. Didn't expect this sort of issues from a brand like Sony.. I told them - on your ads, along with features, you might as well add "Has incredible mura effect!". I hear this is seen on 4K ultra hd models too.. NOTE- this is a defect.. A TV Screen on no input signal shouls be clean; witout spots, patches, clouds.. call it whatever you like.

Anonymous said...

Normally I don't take too kind to people copying my content (not from this article or blog, but in general), but here is a case where you helped preserve some of the internet. Thank you. I will now proceed to do the same. Here's some more info about mura: http://www.magictouch.com/Mura.pdf

Anonymous said...

IM THINKING ON BUYING 2 65' INCH SONYS FOR 500.00 OFF A LIQUIDATION SITE ..ONE SAYS BAD MURA AND OTHER SAYS LIGHT LEAKAGE. I HEARD THEY COULD BE FIXED AT LEAST THE LEAKAGE? NOT SURE IF IT WOULD BE A GOOD IDEA , ANY THOUGHTS PEOPLE?