Why Apple Can't Fix the iMac Yellow Tinge Problem (for now)

Discussion in 'iMac' started by Kavik, Mar 3, 2010.

  1. Kavik macrumors member

    Oct 12, 2007
    About a month ago, I posted a thread speculating the cause of the yellow tinge problem and color/tint variability on the new iMac 21" and 27" models.

    Since then, I received my 27" iMac which had the problem, and a subsequent replacement which was much better but not perfect. After following the thread on the Apple discussion forums concerning this issue, I read this patent document posted by Jacques LaPorte for U.S. Patent #20090135583A1 (received by Apple on May 28 2009) which details "a display system with a distributed LED backlight." According to the patent description, this is a new display technology which includes a "plurality of tile LED sources." Figure 1 on page 2 shows that this panel is intended for desktop systems, i.e. the iMac. Figure 2 on the third page shows the exploded view of the display panel and complicated arrangement of various layers in the panel.

    Apple itself alludes to the difficulty in using LEDs in large panels (larger than 20 inches) such as those in the iMac:

    [0012] Another challenge with utilizing LEDs in large arrays is maintaining uniformity of color in the large numbers of LEDs. ... ​

    [0013] The color and output of each LED also depend fairly sensitively on temperature. The difficulties in providing proper thermal management capability can readily lead to temperature variations across a distributed array of LED light sources. Since the color qualities of LED light sources are sensitively dependent upon their operating temperatures, such non-uniformities lead to unacceptable variations in color from one portion of the display to another.​

    Apple's patent design is an attempt to address these issues using an array of LED "tiles" to deal with thermal and structural concerns as well as individual LED variability. Perhaps some of the yellow screen problems are still due to thermal problems. Most interesting to me is the presence of multiple "backlight diffuser sheets" (item 212) which are between the LCD sub-assembly (208) and the reflector (214). As I posted in my previous thread, someone who wrote to Gizmodo claims that it is distortions in the backlight diffuser sheets which is causing the tint variability in the iMac panels.

    I have to say that this is the most plausible reason for the problem as I noticed in my own iMac what appears to be a "curtain effect" of alternating blue and yellow tint vertical columns that looks like it could be due to a diffuser material that has bunched up or irregular underneath the LCD panel. This may be due to the manufacturing process, dislocation during shipping or the inherent design of the panel.

    Which brings me to the bad news. Since this is Apple's patent and design, this is not a situation of a "few bad panels" from LG, but may be the basic nature of this display technology that would be present no matter who manufactured the part. Many on the forum have commented that the Dell 27" U2711 uses the same display. While the LCD sub-assembly itself might be shared with the Dell, they are not using Apple's patent design for the LED tile array and diffusers. Bottom line is that unless Apple were to radically redesign or switch technologies (highly unlikely until a major revision), I think that the color/tint variability issues may unfortunately be with us for the duration.
  2. StarTzar macrumors member

    Jan 31, 2010
    If you are right on this one, all I want to know from Apple, is will they agree to exchange my yellow tinged 27" iMac when and if this issue ever gets resolved?

    I suspect that AppleCare sales will hit an all time high.
  3. Lordedmond macrumors regular

    Oct 24, 2008
    Tilchestune UK
    Ok if the basic technology with LED back lit screen is flawed then why is it that the likes of Samsung can manufacture TV with LED backlight LCD without a colour cast , they can we have a 32 inch on which is perfect .

    If they can do it why cannot LG
  4. Kavik thread starter macrumors member

    Oct 12, 2007
    I think that Apple's granted patent proves that this is a substantially different design than other LED monitor displays and/or TV's, and is specifically intended for their large screen computers.

    What I was trying to get at with this post is that developing a design like this can take many months (or years), and just as long to put into production. If it truly is the *design* that is the issue, then there is no easy fix without Apple going back to the literal drawing board which could take 6-8 months or longer of reengineering, developing the new manufacturing process, working with the vendor(s), etc. Even making a minor manufacturing or material change might take quite awhile. They may have also decided that this is not practical or economically justifiable to do so, and have obviously not fixed the problem as those with week 9 iMacs with the yellow tinge have reported.
  5. mdewberry macrumors regular

    Aug 20, 2003
    Thanks for the thread - this is interesting research (albeit depressing if true)...
  6. jodr macrumors member

    Jan 18, 2010
    When I went through my own partially-yellowed screen issue with the current iMacs (I bailed after two faulty units) I was definitely frustrated - by all accounts, Apple can very capably repair this issue. Why, then, months after the problem was being written about all over the internet and spurring plenty of returns, do they continue to sell yellow models. This still appears to plague a good chunks of the iMacs in circulation at the moment. Should they not institute some kind of recall, do their own testing and replacement, and not continue to put the burden on the customers to wait for faulty models to be shipped, identified, shipped back, replaced - with the process often repeating itself. I can't believe that this is a relatively minor problem - not just based on my own experience and the experiences here, but also the leaked internal memo and the many floor models I've seen with the issue. Clearly, they're banking on people not noticing or caring, and don't mind providing lots of hassle to those who do. This just seems irresponsible and not particularly user-friendly - am I being unreasonable here?
  7. unamused macrumors 6502

    Oct 25, 2009

    spot on!

    I think the problem lies with the mac fanbois who will back up Jobs and Apple with fervent denial and claim it is user error as opposed to a problem or fault with apple. People need to realize that no company is perfect and call out wrongs and faults when they are due. Just like with toyota, they have gone through so much recently due to all their recalls that their reputation has started to slip.
  8. Btom macrumors 6502a

    Nov 19, 2009

    You may actually be out onto something here, and it is not a good news. There is another troubling paragraph:

    This might mean that the Apple's technology path is not solving those known problems, while Samsung's does:

    Actually there is also a VERY flat (1.2"!!), VERY sweet and even bigger 55" LED Samsung HDTV series, with totally uniform back light. I was trying very hard and couldn't see any kind of a tinge (I know, I am Samsung biased). Allegedly they use LED diodes placed along the edge of the screen.

    Now, where all this leaves us?

    Tom B.
  9. TennisandMusic

    Aug 26, 2008
    Well this is one patent no one will attempt to infringe upon.

    By the way, you should submit this to Gizmodo. It needs to get out there. It sounds like your research is spot on.
  10. Michaelgtrusa macrumors 604

    Oct 13, 2008
  11. Scott1061 macrumors newbie

    Mar 4, 2010
    Yellow screen on 27" IMAC

    My son purchased a new IMAC 27 in Canada, noticed the yellow display, returned it, got money back and went to another store and purchased another unit they had just received in stock. Same issue. He has Applecare and Apple are refusing today, to do anything to satisfy the situation saying they won't fix the screen as the dealer sent in photographs of the display and it looks OK. Dealer is not supporting him nor Apple. What can be done about this?
    I have the same issue with my 21.5 and am asking for a replacement unit but won't know until Monday.

    Thanks for anybody's suggestions on how to make Apple take responsibility for this.
  12. Kavik thread starter macrumors member

    Oct 12, 2007
    Well Tom, it seems that Apple's new backlight technology may solve 4 out of the 5 problems they listed, but obviously fails to achieve "uniform in color" at the present time. Perhaps "easy and inexpensive to manufacture" and "low in cost" are (unfortunately) the deciding variables here. If it's good enough for 95% of the customers, then perhaps it's good enough for Apple. They might just find it more cost effective to placate the discerning minority with returns, upgrades or refunds until the next major design revision.
  13. IndustrialSpace macrumors 6502a

    Dec 31, 2009
    Excellent analysis, Kavik.

    It looks like all iMacs will have this problem.
  14. California macrumors 68040


    Aug 21, 2004
    Another politically-correct green-stupid technology fail.

    The iMac 21.5 I recently returned after owning it for ONE HOUR was a real piece of work. Made the five year old iMac G5 20" it was replacing look like it was brand new in comparison.

    Reminds me of the Macbook aluminum screens that I went through... three before an okay one -- but even that I returned. Note what laptop I am now using in my signature.

    LCDs rule. For my eyes at least.
  15. H4rdc0re macrumors newbie

    Jan 29, 2009
    You might want to keep up with the news. Apple has fixed the problem and are in the process of replacing affected displays. I have mine in for repair at the moment and there are reports on this very website of people with perfect displays now after getting a replacement. And then there is the fact that most of the iMacs out there have always had great looking displays; the 27" iMac at my local Staples certainly does.
  16. vin macrumors member

    Oct 8, 2003
    Keep up with the news? Fixed? Apple is still delivering iMacs with faulty displays today.

    Good analysis from Kavik, but I hope he's wrong :)
  17. Pachang macrumors regular

    Dec 17, 2009
    Huh? didn't you say the yellowing is due to the crumpling of the LED diffuser thingy and not the backlight. Now your saying that it's due to uniformity of the heat?

    There are iMacs out there with uniform colors, so I'd say it is more likely to be the LED diffuser, than uniformity of heat.
  18. H4rdc0re macrumors newbie

    Jan 29, 2009
    There may still be some problems but the OP is talking about how they can't fix the problem. Obviously they can because the problem is not universal. There are plenty of iMacs that do not have the problem so it's obviously not a problem that can't be fixed.
  19. Mr. Biggles macrumors 6502

    Mar 12, 2009
    Western New York
    There are numerous people who claim to have perfect monitors, but when asked to post pictures for others to see, they somehow fade into the shadows or claim they don't have to prove anything. Which to me proves one thing. They have at best 'acceptable' displays, and that's debatable.

    Kavik's comments touch a nerve because if he is right, then the iMac at the present revision is a possible bust.
  20. TropoBone macrumors newbie

    Mar 10, 2010
    Hate to burst your bubble, hardcore.

    I 'enjoyed' my new iMac 27" for exactly thirty-five minutes yesterday (9th March). Serial number gave build as Week 06, 2010.

    Enough of a disappointment for this forum lurker to pull his finger out, register, and post to contradict your assertion.

    3.06 Core2 27" ordered 31/1/10.
    Reseller called last Thursday "good news, just arrived."
    Next 3200km trip to Perth (Australia) was yesterday (9/3/10).
    Picked up unit at 12:45.
    Unboxed and powered up at 1300.
    Odd screen coloration noted at 1315. Googling the problem leads me to Gizmodo and MacRumor forums.
    Did the greybar screentest with the .html from MacRumor thread.
    Confirmed a dirty yellow discoloration, about the size of a man's open hand, lower right of screen. Rough estimate 15% of screen area.
    Checked OS=6.2, did software update and checked for firmware update just in case.
    Still there. Dirty yellow smudge.
    Call Apple Support. Offered a one-offscreen replacement if I take it to approved repair centre. But there's only one approved Apple tech in my town +3000km from Perth and I'm still p!ssed at him for mangling the electromagnetic shielding and leaving two loose torque screws inside when he replaced the HD in an iBook. No way is he doing his first iMac screen replacement on my machine.
    Its a one time offer only. If the replacement LED is tinged, well, maybe I'll have to live with it :( Maybe.
    Back to Apple support guy....Known problem, no argument.
    Back in its box, lug back to DSE Wesley Centre.
    DSE staff surprised. Offered first pick of next two units if I'm prepared to wait 2 weeks till those Week 08 builds arrive. Or refund.

    I didn't like the odds that a known prob since Oct 09, still evident in a machine built mid-Feb 10, would be all gone by late-Feb 10.

    Refund please. Thank you. See you again in June/September.

    Good things about this experience?

    1. Very glad I bought from a physical store, not online. Would have been hard trying to post that thing back to Apple Online. Hard enough lugging it 250m down Murray Street.

    2. DSE Store 35, Wesley Centre Perth WA, scores many many brownie points in my book for the way they handled the problem. They've shipped thousands of macs, have Apple trained staff on the sales floor. News to them. Embarrassing even. But no dodging the problem. 10/10 to those guys.

    3. Apple Support did not bull***** me. Pronounced it DOA within 2 minutes, gave me a case number, and put forward three reasonable options, two of which were possible solutions for me.

    Disappointed? You bet. That was a special purchase. That machine's specs are just right for me. Previous iMac from 2003 ran flawlessly for 7 years in a hot and humid environment. 27" iMac? Beautiful concept. Problems in reality.

    I still want a 27" iMac. But I can't ignore discolorations when I'm photoshopping, esp when its the dirty yellow I'm trying to remove from old/scanned images!

    My options?

    I'm not ordering sight unseen.
    Suppress my dose of 'galloping-must-haves' until June/Sept for the possible speed bump up, also doubling the time since issue first reported.
    Might keep an eye out in the meantime for discounted, refurbished 27"-er at authorised resellers.
    I'll be taking a copy of the html test files to a physical store on a USB drive, and checking the display before I take it home.
  21. mjsmke macrumors 6502a

    Mar 2, 2010
    I agree. dont buy apple products online. I was told i could refund in store untill i tried to.

    I had to order mine online due to its spec...3.33GHz/8GB RAM 21.5"

    Ordered on 10/FEB/2010

    Arrived 7 days later

    phoned applecare regarding the yellow screen after 2 days of use. They said take it to a store. Store said they will replace the screen within 3 weeks!!! NOT HAPPY. several emails and phone calls and they repaired it in 4 days. HAPPY. got home switched it on.... yellow screen. NOT HAPPY. phoned up again. they said i am a priority customer and will have a replacement in 6 days. KINDA HAPPY. 2 weeks later. NO REPLACEMENT.

    I really had to kick off on the phone to apple and trading standards for them to agree to an in store refund if the replacement is not ok.

    Ive decided to refund it even if it is ok when i receive it. I dont want apple computers anymore. Even though ive been using them for over 10 years.

    I am going to make a custom PC with the same components as an iMac for the same price. but ill buy a proper screen.
  22. TropoBone macrumors newbie

    Mar 10, 2010
    Snap! Me too.

    I want 27"+. I want quad core, and I want OSX.

    Take a look at tonymacx86 and osx86. Might be a learning curve but..... "what one man can do, another can do!"
  23. Max(IT) Suspended


    Dec 8, 2009
    I have seen a lot of Samsung LED TV (I have one), and they have gradient in some way.
  24. TropoBone macrumors newbie

    Mar 10, 2010
    I missed an important point in my first reply, sparked by Hardcore's comment.

    "February 8th. Apple has initiated steps to rectify the Yellow Screens with a one-time only screen replacement service. The repair/replacement service are quoted to take 3-5 days. "

    Thats about, or a bit before, the Week 6 build date of the machine that I returned with an obvious yellow tint.

    (and a tint, a smudge with an irregular boundary, not a gradient.)

    Why keep building and shipping the problem units?

    Were they hoping that I/others would not notice?

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