LED Screen and Headaches?

I'm looking to buy a T400, but I have some concerns about the LED backlight.

I have found that I tend to get headaches when people are using LED flashlights, and I also have trouble when I drive behind someone who has those LED brake lights on their car. I get headaches and feel nauseous.

I've done some research and there seems to be a small, but vocal, group of people who have problems with LED screens, but their problem occurs when the screen is at half brightness. Apparently LEDs were designed to be either on or off, and the workaround has caused some problems for people. I don't think this is my problem, but who knows.

I'd really like to get the LED backlight, but if it's going to be a headache (both literally and metaphorically), it's not worth it I guess.

Has anyone experienced headaches or eye strain as a result of the LED backlight on the screen? Any related thoughts?

Thanks

 

if I am infront of a screen enough I get a headache no matter what the screen is.

 

I have read that LED screens should be superior to CCFL for reading since they do not produce any flicker - CCFL screens are constantly, though imperceptibly, flickering. Also, the power output or brightness of a LED is apparently more easily adjusted than that of a CCFL tube, allowing an LED to be adjusted at finer gradations and to a lower level.

 

I had the same issue many years ago. It is not the screen - it is called Astigmatism. Go to eye doctor. You could need glasses with no diopter, but only to fix this like in my case.

 

I do not think it is accurate at all to say that LEDs are designed to be on or off. Certainly this was the function they were originally used (indicator lighting) for but since then they have become bright enough to be used for other purposes (task lighting, ambient lighting, backlighting). From how I understand LEDs to operate I know of no reason that operating them at 50% brightness as compared to 100% brightness would cause problems. AFAIK the brightness response curve for nearly all LEDs is almost linear as voltage is varied so not much different is going on at half brightness as compared to full brightness.

Regardless of a display being CCFL backlit or LED backlit there will be a refresh rate and I think this could be the culprit in creating eye strain/headaches for some users.

Do you get headaches when looking at a normal LCD display? I wonder if your problem has more to do with light in general rather than specific sources of light.

Anyway, if you already perceive that LED lighting gives you a headache, then why are you toying with the idea? I'd say forget about it.

 

I can tell you, in my experience, the LED backlight is MUCH easier and on the eyes. My eyes are great, and I get headaches too if I am in front of the screen to long.

The brighter and more adjustable the screen setting, the less eye strain and fewer headaches.

Glossy screens, while they look nice, can create more eye strain that matte screens.

I used to only be able to do computer work for about 7 hours before my eyes would punk out. I can go 10 now with now issue. I think the screen has some factor in this.

(Obviously, get up from the computer every hour and look far distances outside. Go outside, even for 2 minutes if you can. You will feel better a d not be as drained at the end of the day.)

 

If you are sensitive to LED, you would hate driving in Los Angeles (besides the traffic). Every stoplight has LED in it now.

Are the people sensitive to LED backlight have a glossy or matte screen? Perhaps LED + Glossy is more aggravating than LED + matte.

 

Yeah, I'm thinking that it's not worth it, but I was kind of hoping that somehow it wouldn't be a problem in this case.

Anyways, here is a link to a discussion on an apple forum about people having problems related to the LED backlight on the new macbook pros. One of the points made is that there was an issue when it came to using the LED at partial brightness, but again I don't think that's my problem.

I've never had any problems looking at regular screens for long periods of time, or at least no more problems than most people. It's just something about LEDs that bothers my eyes I guess.

I guess I'm just going to have to go with the WXGA+ TFT :/

 

The screen that is used in CCFL and LED are the same. The only differnece is back lighting. There is no flickering in CCFL, you are thinking of CRT (cathoray-tube) monitors. CRT's are your old boxy heavy TVs and Monitors.

 

The thing is that the new MBP has a super glossy, Glass Screen + LED backlight. I have never heard of LED-backlight problems with other manufacturers like Dell, HP, etc.

Perhaps the synergy of the new Glass Screen + LED backlight on new Apple MBPs cause people problems.

 

LED brake lights and cheaper LED flashlights use low frequency pulse width modulation techniques for dimming. When these lights are not lit to full brightness, they will flicker at rates that can make some people nauseous. The effects are similar to staring at an CRT monitor (or TV) with a very low refresh rate. It is the flickering that is the issue, not LED light per say.

If you are sensitive to low frequency flickering and you wind up with a LED backlight that uses low frequency PWM to control screen brightness, you will have problems when the screen is not at full brightness. You might be able to avoid the problem by running the screen at full brightness, but there's no assurance that the backlight dimmer will run the LEDs constantly even at full brightness.

There are ways to dim LEDs without inducing nausea in a percentage of the population, but device manufacturers are seldom prepared to spend the money.

 

I'm not so sure that PWM dimming is the culrpit. From the brief reading that I've done, PWM units for backlights in the Macbooks in question (link below) have a minimum refresh of 100Hz and maxes at 20KHz - even the lowest refresh seems too high to cause a problem with eye strain.

Is there documented problems with LED backlighting on non-Apple products? I can't find any. It seems that this may be an apple-specific implementation. Anyway, the results are not good for these Apple users: migraines and vomiting from a couple of threads I've read.

Here is a good read: Apple MBP LED eye strain

 

It's not just the frequency but also the duty cycle. 50Hz at a 50% duty cycle is flicker free but 100Hz at a very low duty cycle can be perceptible under certain circumstances.

Having looked over that thread I'd say the issue is the psychotropic effects of flicker acting through the visual system. Certain flicker rates can have profound effects on people--altered moods, migraine headaches, or even epileptic seizures--and the Macbook effects are in line with this.

 

What are your thoughts on this being a Mac LED backlighting specific problem? When searching I can only find complaints about headaches from Mac owners.

Not surprisingly for Mac users, despite nausea, vomiting, and migraine headaches, the thought to switch to a different notebook doesn't seem to be an option in the discussions.

 

I have no idea if this is Mac specific or not.

 

Well, I know that I get headaches from LEDs out in the real world: flashlights, brake lights, etc. So that aspect of LEDs causing headaches is definitely not Mac, or even laptop, specific.

However, it may be that I would only have a problem with the Mac implementation of LED backlighting, and that the Thinkpad LED backlight would be fine.

That said, there does seem to be a relatively sizable group of people who have problems with LED lights in general. If the problem does indeed manifest itself in laptop screens, we could have a real problem if LED backlighting becomes as ubiquitous as widescreen format displays.

Either way, I'm taking the safe route at this point, and ordering a T400 with the WXGA+ TFT screen.

 

I'm having problems with headaches and eye strain since the day that I got my new Dell XPS M1530. I love the computer but I might have to send it back because it is unbearable. I get headaches within 20 minutes of use. And prior to this I never got headaches. And I spend a lot of time on the computer since I am a researcher and a student.

There is another thread in this forum that talks about this problem. It is not just apple MBP. checkit out here: (I can't post urls on this site so I omitted the prefix.)

forum.notebookreview.com/showthread.php?t=285025

 

Hmm, thanks for the feedback and link. This is definitely a problem and I wonder what laptop manufacturers are going to do about it.

I'm glad I didn't get the LED screen, especially since I saw a friend's new MBP. His screen appeared to flicker to me, but not to anybody else there.

The fact that an LED screen can be so uncomfortable (at least for people with eyes like mine), is enough to scare me off completely, even though the problem might not manifest itself in on a non-glossy T400 LED.

gpzbc's link with the prefix restored: http://forum.notebookreview.com/showthread.php?t=285025

 

For all of you doubters out there. I replaced my LED screen for a non-LED screen and the eye strain headaches were gone instantly. 100% gone!
No doubt about it.

 

I just want to re-emphasize that I traded in my LED glossy screen for a non-LED glossy screen. My eye strain headaches were gone instantly and I have never seen them since despite the fact that I am still using a glossy screen.

Oh, and by the way, I went to the eye doctor recently and my eyes are approximately the same as they have always been.

There is no doubt that LED was giving me a miserable headache. Perhaps it was me and not all users will have the same reaction. But, with that being said, I would urge all to take caution with the new LED screens.

 

goto a store and try an led screen out then youd know

 

Hmm.... but I'm assuming that trying it out would involve more than looking at it for a couple of minutes. Go to the store and type an essay on it and then see if you have the headache.

 

I have a T500 LED and love it. No headaches or eye strain.
But I have also turned down the brightness to fix the default washed out colors and excessive blue hue.

In the ATI Catalyst Control Center, I changed these brightness settings to.

Blue -60
Red - 35
Green -25

I also changed the Green Contrast from 100 to 95

 

@joey-t,
Tried your settings on my T400 high nit LED and they work fine for me - very good and thanks.

Gary

 

Been using my new x200s without such problem--even forgot I had worried about it before I bought it when reading such comments.

 

Sorry old thread it seems..... still valid. T400 LED means headache. Any new findings ? T61 CCFL no headache can work on it for hours. Will try CCFL X200 and report.

 

Just to confirm my initial findings, I haven't had a single eye strain headache since I got rid of my LED screen 14 months ago.

 

I'd recommend using an anti glare LED/RGB LED screen as a must since the glare type screens produce lots of reflections (especially if you have a sensitivity to bright colors). You can adjust the brightness to your liking anyway.

 

While I'm sure that anti-glare screens will help some situations, my problem was with the flicker of LED screens. It wasn't about the brightness or the glare.

This flicker test revealed the problem for me.
http://www.csse.uwa.edu.au/~lucas/background.html

On my LED screen, the images crawled around like a plate full of worms. On my non-LED screen, it was stationary and fine to look at.

And here is another flicker test.
http://www.lagom.nl/lcd-test/inversion.php

 

Just checked your links on my RGB LED screen with no flickering. It's probably your specific screen. AFAIK LEDs should flicker less than CCFLs.

 

Interesting.

I've never experienced a single headache or eye strain using my personal T400 in the twenty months I've owned it. It has an LED screen.

I replaced my work laptop with a T500 three months ago, it also has an LED screen -- I use it nine to ten hours per day.

Clearly a person's experience can vary. I'm sure this was a problem for you, I post my experience only to identify for other readers that this is not an issue for all people. As to how many people it is an issue for, readers should scan/search the forums to develop their own impression. I only know that LED backlit T500's and T400's are my company's (current) laptop for several months and I've heard of no reports of issues from my employees or other managers employees.

 

I agree. It is not a universal problem and results may vary. I'm just encouraging people to spend a little time on an LED screen to see if they are one of the ones that experience these problems.

I wouldn't call the problem widespread, but there are enough of these cases to make me concerned. Here are a few similar threads.
http://discussions.apple.com/thread.jspa?messageID=8372390
http://forum.notebookreview.com/showthread.php?t=285025

I actually suspect that the technology was new enough, or poor quality enough that it irritated those with a sensitivity to flicker. I imagine that the technology will get better and that we will see less and less of this. I'm hoping that is the case because I loved my LED screen and I hated having to give it up. So my hope is that it will no longer be a problem when I get my next computer.

 

Seems I indeed have the can of worms effect on my T400 but not on the T61. The T400 is LED. Thanks for that, now I can take the tests and do it in shops where some have WIFI connections on !!!!

No can of worms on X200s ... but yes to ghosting

 

I know this is an old thread but I want to try to save someone the headaches (pun intended) I have been through over the last few days.

In an upgrade to my Dell Vostro with WUXGA screen I just received a T510 with the 15.6" FHD Display (95% Gamut, 270nit) with LED Backlight. The instant I turned it on I felt my eyes starting to tear up.

After a few minutes it was very uncomfortable.

I assumed that it was the anti-glare coating on the screen as everything looked a little shimmery to me although the slightly smaller pixels on my Dell (glossy screen) look solid and clear.

After several days tinkering with the display settings to try to get used to the screen, my son asked why he could see multiple shadows of his finger when he moved it in front of the screen. I explained that this was because LEDs are usually dimmed by turning them on and off for different amounts of time. Then I suddenly realized this may be my issue.

I turned the screen up to full brightness and, voila, it instantly got easier on my eyes but is obviously way too bright. I have used the Nvidia controls to turn down the actual display settings as much as I can but it is pretty much too bright to use like this except in a very well lit room.

I am worried that other LED back light laptops are going to have the same issue for me but this one has to go back as it is pretty much unusable.

I can't seem to find out what the refresh rate on this back light is but given that Lenovo's screen flicker is making this device unusable for me I don't think I should be paying the restocking fee. But we will have to see how that goes. Any suggestions?

So I can confirm that LED back light flicker can cause eye strain.

 

First make sure the refresh rate is set at highest possible. My refresh rate by default in Win 7 was set to 50hz for some reason instead of 60hz.

Next, the easiest way to see if your display is really flickering is to take a video camera or regular digital camera (video mode) and look through it. The screen will be flickering through the camera if it is at all. The LG led panel in the T400 doesn't flicker at any brightness. The Samsung only starts flickering after a few minutes and only at minimum brightness.

 

The refresh rate of video card will not affect modulation of the backlight in any way - this is completely notebook-vendor dependant.
Even high frequency backlight can appear flickery through camera, it depends on fractional reminder between screen and camera refresh frequencies, not absolute difference.
All laptop TFT screens adjust their backlight brightness by PWM (CCFL, LED, regardless). However what may vary is the frequency of modulation - obviously higher frequency makes it less percievable.

The "moving your hand in front of the screen" is the best test. If you will see shadow of the hand split into several distinct "ghosts", the backlight modulation is low-freq and such screen may cause problems on long viewing.

 

Can anyone point to specific screens/brands/laptops that do not cause this issue if one is sensitive to it? I have searched and searched and can't seem to find anyone addressing this issue.

My Lenovo has gone back and now I don't know what to buy (the local stores don't generally carry 1920X1080 laptops unless they are 17" so I can't go an look there.)

 

it's honestly called turning down the brightness.   refresh rates are the same on CCFL as they are LED panels.   the difference is that LED is typically much brighter and most people run their displays much, much too bright.

i can give myself a headache if i run my 400 cdm^2 30" CCFL IPS display at 50% brightness.   typically i run it at 25% brightness and 35% contrast during the day, and less on overcast conditions or at night.

 

"it's honestly called turning down the brightness. refresh rates are the same on CCFL as they are LED panels. the difference is that LED is typically much brighter and most people run their displays much, much too bright."

Sorry but this is absolutely incorrect. I had the Lenovo side-by-side with my Dell and tweaked every setting I could to get the screens to look the same (color, gamma, brightness of the backlight, brightness of the LCD etc.)

The only way I could look at the Lenovo for an extended period without the text appearing to shimmer was by turning the brightness up full. And, as you say, this is far too bright in most circumstances.

Yes my Dell CCFL backlight does also flicker when not on full brightness but it does not bother me for some reason (although I mostly run it at full brightness because that is not too bright like the LED.) I will see if I can measure the flicker frequency on the CCFL for comparison purposes. The finger ghosting when moving the hand in front of the screen is clearly more pronounced on the Lenovo but I am not sure what that means. The finger ghosting effect doesn't get as strong as that on the Lenovo until the Dell is down to 25% brightness.

The fact that the LED backlight is brighter may have some bearing on the situation. But probably only that the pulse width for the on-cycle is narrower for the same corresponding brightness on a CCFL screen. I suspect this has some bearing on the reaction of those people who are sensitive to this flicker. I.e. for the same relative brightness we are seeing a short very bright LED pulse but with a CCFL we are seeing a longer less bright pulse.

Trust me, I would not be paying $300 in shipping and restocking fees if turning down the brightness would solve this issue.

 

Quick question:

What are the advantages of setting the refresh rate to the highest possible setting?

By fault, on my R400, the refresh rate is set to 50hz. Following your suggestion, I changed it to 60 hz.

 

You are mixing up screen refresh and backlight modulation frequency. For LCD screens these are completely separate and independent.

Screen refresh rate defines how quickly picture could change. This generally could be set by user (50HZ, 60Hz, 75Hz, etc). It defines how quickly display "blinks" for CRT monitors only.

Backlight modulation defines how quickly backlight "blinks" to make it less than 100% bright. This could vary between different LCD panel makers, since it's being set in the panel electronics or by notebook maker when they make backlight control board. It's generally not changeable by user.

I was unable to find any percievable flicker with my W701, on any brightness. Did a moving hand test and no ghost images.