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Anyone noticing screen flicker?

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Soundchasr

Senior Member
Mar 24, 2011
196
7
Not only do I have light bleed but I'm also seeing screen flicker. I really want to keep this device but I'm getting sick of this...
 
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Cheater912

Senior Member
Jul 14, 2012
423
103
New York
The first thing I noticed when I turned on the device was the light bleed. Its pretty bad, and I normally don't mind those types of things. No flicker here though.

Sent from my Nexus 9 using Tapatalk
 

reggie14

Senior Member
May 29, 2010
186
25
I don't have light bleed, but I do see flicker if the screen brightness is turned down. It's reminiscent of the original Nexus 7, which had the exact same problem.
 

androidoholic

Senior Member
Sep 17, 2011
438
153
Simi Valley, CA
I have the flickering too...really annoying. I was hoping that this would replace my iPad but it's not looking good. Although lollipop is pretty amazing so far.
 

mkygod

Senior Member
Nov 11, 2013
188
39
Does it only happen you adjust the brightness? If so, i dont think its a big deal as long as it doesnt happen during actual usage.
 

spontaniusf

Member
Nov 7, 2012
7
0
I noticed the flicker issue when I first was using it. I then turned off auto brightness from the main settings and started using Lux Auto Brightness and the issue has been resolved as far as I can see. I suspect this is an issue with the Lollipop build's brightness manager and not a hardware issue from the backlight. Also as far as bleed goes, there is apparent bleed when viewing the screen at an angle and looking directly at the edge, however I have found that it is a complete non issue in normal use (even in a fully dark room), which stands in stark contrast to my Nexus 10 which has noticeable edge bleed when viewed straight on.
 

StuMcBill

Senior Member
Feb 13, 2010
1,895
120
No flickering, but the auto brightness is very weird! It goes from extremely bright to extremely dark without me actually moving, same light conditions?
 

bobmarleo

New member
Nov 5, 2014
3
2
Do you think that this issue can be solved via software update, or is this issue hardware related, and therefore cannot be fixed easily
 
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PartyMango

Senior Member
Feb 25, 2011
136
19
Wien/Vienna
This issue seems to be related to auto brightness/adaptive brightness: The same brightness level set manually doesn't flicker.

Seems to be a software issue to me, and it seems highly likely every Nexus 9 flickers with auto brightness on (and at low relative brightness setting) in low light environments.
 

bobmarleo

New member
Nov 5, 2014
3
2
This issue seems to be related to auto brightness/adaptive brightness: The same brightness level set manually doesn't flicker.

Seems to be a software issue to me, and it seems highly likely every Nexus 9 flickers with auto brightness on (and at low relative brightness setting) in low light environments.

But, my screen flickers when I am on a constant brightness level. But, it doesn't show up as much when the screen is on at full brightness, just when the screen is at half brightness or just below half.
 
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PartyMango

Senior Member
Feb 25, 2011
136
19
Wien/Vienna
But, my screen flickers when I am on a constant brightness level. But, it doesn't show up as much when the screen is on at full brightness, just when the screen is at half brightness or just below half.

I guess we aren't experiencing the same issue, then: My screen only flickers with adaptive brightness enabled in low light conditions, seems like it is constantly readjusting the screen between two brightness values.

My Nexus 9 doesn't flicker at any constant brightness setting.
 

Valynor

Senior Member
Nov 22, 2008
431
160
Yep, my Nexus 9 flickers as well.
About 15-20% brightness (fixed). It doesn't flicker all the time and it goes away if you change the brightness level or even by itself if you change the app you are using.
This leads me to believe this might be a software issue (N7/2013 had this too when it came out).
 

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  • 4
    i encourage you to read post #26 in this thread.

    Informative post, but this is not an issue of just normal LCD issues that may be perceived by some and not other s depending on the persons eyes. It is a distinct flicker that is a direct result of low ram. Again, low ram situations are causing the majority of the issues with this device. Anyone who has screen flicker, I guarantee if you go to developer options, process stats, while screen is flickering its in the 'critical' or 'low' ram state. I think its a bug with the GPU driver(dynamically allocated memory I believe), and low ram situations are what cause this. After a fresh reboot, the issue will disappear for a while until memory fills up- and it will as there seems to be MAJOR memory leaks with this device. I do think 2 gigs are OK as long as memory leaks are fixed.
    Maybe I'm wrong- but last few times this has happened, when I check during screen flicker, ram is low/critical. It never happens when ram is normal.
    3
    Hi

    The flickering issue is a known problem in the industry with these types of display. Backlights are controlled by PWM (pulse width modulation), where the LEDs are very quickly turned on and off thousands of times a second. We can't see this on and off happening, it's too fast, we just perceived the LEDs as being dimmer or brighter. The dimmer the display the more the LEDs are off compared to on in a second.

    Over the top of this switching is a grid of pixels that also refresh and flicker independently, again to fast for us to notice, but sometimes the frequency of changes on the LCD panel line up in such a way with the frequency of the backlights that cause us to see a brief change in brightness.

    The best example many times slower of what is happening is something we've probably all seen, a blinking LED that we look at or see from the corner of our eye that appears to miss out a flash. This is because at the moment the LED flashes we blinked and missed the flash, we can with a bit of concentration deliberately blink at the right time to make it seem like the LED is constantly off. If the off blink period is very quick with a longer on period, we could do the opposite and make it seem like the LED is constantly on by blinking during it's off period. This is what is happening on these panels, for a brief period things line up so that the panel is flickering opposite to the backlight and it appears to change in brightness or flicker.

    This is why the problem is often worse at lower brightnesses, because the off period of the backlight is much longer, and we are in a dimmer environment so any flicker is immediately more apparent.

    As components vary in tolerances different devices might exhibit the problem at different brightnesses or maybe not much at all, or one person seems to tune into this brief flicker where for another person they don't notice it.

    The HTC One X had large complaints of LCD flicker, this was partly resolved by a firmware update. The update simply applied different algorithms to the pulse width modulation to dim the backlight at different frequencies to minimise the effects, probably pushing the problem to a different brightness setting where it was not so noticable. Indeed you can read reports of people that had no flickering problems before, only to start to suffer it after the fix was applied.

    Mobile devices like tablets are difficult to eliminate these problems completely because they need to support a big range of brightness and are starred at intently. They have very bright LEDs for outdoor use, but these then need a long duty cycle of being off in order to make them run at a much lower brightness. Also the LCD display with it's natural flicker which interferes with the backlight will see that frequency of that flicker change as it ages, when the device is hot or cold, or when the battery voltage is high or low. Adaptive brightness adds another set of variables to the mix, as does a fast CPU that will cause very fast voltage fluctuations which can then contribute to the problem.

    If you look at the display while it flickers from an acute angle, which means you are looking past the LCD display into the backlight directly, hence the washed out colours (not so easy on an IPS display with it's wide viewing angles) you will likely see no flickering, with the flickering returning only when you are looking directly into the screen and so looking through the LCD panel against the back light. If you could take the LCD panel and hold up against a window while it was flickering, so removing the backlight from the equation, again you would see no flicker, the problem is when they come together.

    So it isn't a fault, it doesn't indicate that the back light is about to fail, and may be reduced or eliminated by a firmware update in the future. An exchange might be lucky for you, might be worse, or exactly the same. When other people say they have a perfect display with no flicker, it may just be because they have different settings applied or just don't notice it.

    Regards

    Phil
    2
    Sorry for answering to a post that is this old!
    I recently RMAd my Nexus 9 because of the screen flicker. The new device's screen has a different hue, just as you noticed with your device. I am now hoping that this is due to a different screen being built into this unit, and maybe a screen's hue can be linked to a certain batch of screens, so you could recognize a screen's probability of starting to flicker based on its hue. Do you still remember what hue your two devices had? What hue did the device have that did not suffer from flickering?
    Greener tinted displays never flickerered. The warmer (in comparison) displays flickered, but the frequency varied device to device. However, the warmer displays also had significantly less backlight bleed and seemed more color/whites accurate overall though. Greener display seemed a bit sharper though (may just be the hue difference making it seem sharper to my eyes)

    (I've see a lot a Nexus 9s and I'm convinced there are two different display sources.)

    I currently have one of the warmer displays on a sand model. I've had it over a month and I've only had it flicker once in that whole time. Haven't seen it flick in a least a month of use since. Definitely a hardware issue from my experiences.
    2
    My second replacement tablet has this. Noticed right away. The first two did not and I had them for a couple weeks. The second replacement also has a completely different hue and brightness.

    This makes me think the flickering is a hardware issue.
    1
    Im seeing flikkering too.....
    Only when brightness is low.