BenQ XL2411T w/ Lightboost - Faulty?

Hi,

I recently purchased a XL2411T. I have done the hack to allow Lightboost to be enabled while in 2D mode as per several threads.

I have noticed that the upper left hand corner of the screen is a fair amount darker than the rest of the screen. It seems to only happen when Lightboost is enabled.

Is this a faulty screen or a side effect from the lightboost? I have only had it for 2 days so would ideally like to know if it is faulty or not to get a replacement.

Thank you

danielblackmore said:

I have noticed that the upper left hand corner of the screen is a fair amount darker than the rest of the screen. It seems to only happen when Lightboost is enabled.

Is this a faulty screen or a side effect from the lightboost? I have only had it for 2 days so would ideally like to know if it is faulty or not to get a replacement.

Click to expand...

LightBoost does push the limits of LCD technology, but I don't have such brightness non-uniformities on the XL2411T.

That said, there can be increasd artifacts in different parts of the screen (e.g. top edge versus bottom edge). LCD's that are pushed to their limits can show things like faint horizontal lines in a corner of the screen. That also occasionally happens with IPS overclocks (unrelated to LightBoost, but more related to pushing an LCD panel's to its very limits) -- as an LCD starts getting pushed to its limits, colors and uniformities can degrade. There are also LightBoost specific artifacts in that slightly different looking faint trailing artifacts may occur at the very top/bottom edges of the screen (not noticeable in games but noticeable in motion test patterns. Caused by the linear scan of the LCD panel (while backlight turned off) versus the all-at-once strobe backlight -- meaning pixels can be in slightly different stages of transition (e.g. say, 95% complete transition at bottom edge versus 99% complete at top edge, causing slight difference in trailing artifacts) when the backlight is flashed stroboscopically at a precise time. All of these minor artifacts are normal for 3D Vision (and for LightBoost) due to LCD being pushed to its very limits to make the technology possible.

However, what you said can be a defect, depending on how major. A large brightness non-uniformity (that shows up in photos, and blatantly noticeable in games) is a big problem. Is it like a corner being twice as dim / twice as bright? If you do return, tell them 3D Vision is defective -- it wouild manifest itself as a problem within 3D Vision, since LightBoost is officially enabled with 3D Vision (The LightBoost's motion blur elimination benefit is not an officially listed feature).

Hi,

Thanks for your reply.

I have noticed the feint horizontal bars across the corners which I dont really mind.

I wouldn't say the corner is twice as dark as the rest, I would estimate about 20% darker. Its not noticeable in games at all really, its just more noticeable when i'm browsing and stuff like that as I can see the gradient going across my browser window.

The dark corner does seem to reduce when I change the contrast though

I just noticed the left upper corner is indeed darker on my QE

A 20% difference seems to be quite significant (that's bigger than both of my XL2411T and VG278H), but it's within the realm of being normal for some LCD's -- they have uniformity problems of that degree in many models, even non-TN models. But this does seem quite borderline.

Alas, if this is normal for VG248QE's, then claiming a warranty may not get a better replacement model.