Example of backlight bleeding?

[daftpunkit]

I just noticed this when testing dead pixels in a dark room....

http://img484.imageshack.us/img484/1734/dell2405fpwbleed25jv.jpg

http://img456.imageshack.us/img456/4728/dell2405fpwbleed31in.jpg

look in the corners.

When they is discoloration in the top left, bottom left, bottom right corners. When i do a all Black cover.

Is this noticeable for other 2405FPW users?

I used the DPB (dead pixel buddy) to test this.

 

[daftpunkit]

also the 4 usb slots on the monitor and the memory card readers don't work. I got one cd with the monitor but doesn't have anything to install, just a readme. From what I read XP should automatically detect the usb's and memory card readers. None of it is working for me.

I have it connected thru DVI to my computer too.

 

[Burrbaby]

about the card reader - did you plug the usb cord into your monitor (square plug on one end normal rectangle on the other). the card reader doesn't interface through the dvi connection.

 

[Rage187]

lol plug in the usb cord

your hub isn't going to magically work through the DSUB or DVI it requires a cable just like every other USB hub and card reader.


and i see absolutely 0 backlight bleed.

 

[allies]

I don't see any backlight bleed at all either...

 

[Ronin]

After using several, I can't see the bleed, either.

 

[daftpunkit]

heh it was my computer not the monitor. my usb on my tower's top case is not plugged in right. But yeh, I did hook the cable up when i set it up, not that stupid . Backlight bleed is not there, but there are these lighter patches of black in the corners, the pics don't do it justice. Lets just say its not a smooth consistent black. it looks likes thats where the lamps are behind the screen. Not sure how LCDs are constructed, but if it is Liquid Crystal Display (right LCD?) then the liquid part is not so thick there? Its not apparent at all except if i do the black lvl on the DPB or when my computer boots up and goes thru the checks before entering windows.

 

[daftpunkit]

Could other electronics nearby it distort it? Like CRTS near non-shielded magnetic electronics, like speakers, would distort the screen. All I have near my LCD is my alarm clock and DVD players and 2 satellites (Logitech Z-5500s. I will move stuff around and see if that might be the case.

 

[daftpunkit]

http://pics.bbzzdd.com/users/daftpunkit/Picture.jpg

maybe that is a bit better. But look more noticeably in the top left. Don't you see that pathc of lighter black?

 

[Thorny]

I see what your talking about, but don't have a clue what it is

 

[daftpunkit]

http://img476.imageshack.us/img476/2213/picture1jn.jpg

i fiddle with my camera settings a bit, this a little more exaggerated then it shows because it picked up any brightness. Its not that bright but shows the 'problem' areas. Just asked 2 other people who has 2405FPW and a 2005FPW, and they say they have it too, just thats its a general problem iwth LCDs and their issues with blacklevels.

 

[Patt]

Very faint, but I see it too. If you have to work that hard to see it is it really an issue?

 

[Keeir]

There are a few things those spots could be

#1. Backlight Uneveness
Most LCD monitors are powered through just a few strong backlights. Across such a large panel, a bit of uneveness would not be unusual. This would occur across all colors and not be visible if the monitor is turned off.

#2. "Mura" Defect
A Mura defect is a common name for a whole range of LCD defects, but the the simplest way to sum up the group is that the many layers that make up the LCD are not positioned correctly or the actually pixels are all the same size. Again, on such a large screen, a small bit Mura defects would not be unusual. I have a small one at the top of the Dell 1905 I am typing this on.

#3. Backlight Bleed
Very similar to Backlight Uneveness, but perhaps it would be good to say that in the case of backlight bleed that the monitor is capable of producing a higher brightness than listed?
Typically something called Backlight Bleed is a very signifcant case of Backlight uneveness where it definately interfer with use of the monitor....


Anyway, I would do similar comparison tests using solid colors such as blue/red in a "normal" lighting condition to determine if your monitor has a serious problem. From the pictures, I would say your level of backlight uneveness/Mura effects is very acceptable/good given the size of the monitor as well as the price.

 

[fliguy84]

Originally posted by: daftpunkit
http://img476.imageshack.us/img476/2213/picture1jn.jpg

i fiddle with my camera settings a bit, this a little more exaggerated then it shows because it picked up any brightness. Its not that bright but shows the 'problem' areas. Just asked 2 other people who has 2405FPW and a 2005FPW, and they say they have it too, just thats its a general problem iwth LCDs and their issues with blacklevels.

i think i see somebody's face on that screen :Q jk

 

[AndrewZorn]

my first 2405fpw was like that, actually a bit worse, top left and bottom right. exchange made the problem nowhere near as bad (but its still barely there). i also have a greenish bar that runs vertical a little bit off center, but i cannot even see it when brightness is set properly (i set it to 0 looks so much better than 50)

BUT ive been thinking about exchanging this one lately too. has anyone noticed this:
i turn brightness to ZERO to make blacks blacker and the flaws i have less visible. it doesnt affect colors/whites much at ALL using DVI on my PC. however, if im using component input and i try to make it look the same as PC, i dim brightness and even by the time im down near 40 its already getting hard to see.
meaning, brightness on DVI just adjusts the blacks mostly which is what i wanted to dim, but on component (and probably the other analog sources) it dims the ENTIRE picture and NOT the blacks.

problem is not only is black more of a GRAY when brightness is at 50, but i can see the top left/bottom right bright spots as well as the vertical line when brightness is this high

any suggestions? because i kind of need to do this soon...

EDIT also like on PS2/xbox when i view it widescreen it stretches it to 16:10 not 16:9. how do i make the monitor put little black bars on teh top and bottom?