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LCD Question

Discussion in 'Projectors, Screens & Video Processors' started by Fjorko, May 8, 2003.

  1. Fjorko

    Fjorko
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    IS it true that the LCD panels in projectors can have a kind of image "burn-in" over time like a CRT tube of a TV can burn the phosphors on the screen ?:confused:

    IS it also true that LCD image intensity fades with time i.e. the picture becomes darker end less bright over time ( not relating to lamp off course ) ?:Lesson:

    Cheers:D
     
  2. gothmog

    gothmog
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    There is no image burn in in the CRT sense, now worries with games TV channel logos etc.

    The second question is a bit loaded, it is true that the bulb will emit less light over time although the amount will vary depending on many factors. The bulbs generally fail by exploding not becoming too dim :) This is why there is an hour counter that will not allow you to run the bulb past it's recommended life without changing it :D

    There is the more sinister issue of degradation of the LCD panels themselves, I've certainly heard stories of AE100's with thousands of hours on them having problems, but again most of this type of problem is likely to be product specific.

    If you're buying a new one there is no way to know in advance if it's going to age badly or indeed have any other reliability issue, only that it's a newer generation so lessons should have been learnt etc ;)

    -- Jon
     
  3. Fjorko

    Fjorko
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    OK........... so if you change bulbs when necessary.......it should be performing the way ( or close to ) it was when you first got it ( assuming no other parts have failed in the mean time )

    ?

    P
     
  4. LV426

    LV426
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    I have never seen any evidence to suggest that LCDs deteriorate over time - aside from the 'wear' on the lamp.

    I had a Sony LCD RPTV for several years and then sold it to a relative who is continuing to use it. It is now about seven years old and, with what I'd describe as a fairly 'normal' pattern of use (say, 2-3 hours a day on average) and hasn't deteriorated to any detectable extent.

    In the company for which I work, we use direct view LCD screens for certain positions. These things spend the entire working day powered on, with a fairly static menu display permanently visible on part of the screen. They show no deterioration (screen burn, or similar) after several years.
     
  5. gothmog

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    http://www.extremetech.com/article2/0,3973,1049289,00.asp

    Although the study is 'dubious' in the sense it is sponsored by TI and they got the answer they were looking for, ie DLP is great etc.

    It cannot be denied that the LCD panels of the projectors they tested did suffer damage. Whether

    a) LCD PJ design is better now
    b) These are IT projectors where lumens are king, so dimmer HC PJ's should be less prone
    c) There was a flaw in the test methodology

    can be debated, well, forever :D.

    The responses from Epson and NEC are particularly interesting, NEC seem to claim it's a know issue, the Epson guy seems to say it's a load of bunk ;)

    -- Jon
     
  6. John_N

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    interestingly enough, I did see LCD "burn in" approx 6 years ago in a piece of professional audio equipment that I was working with. This was a hard disk editing system with a colour LCD screen with soft keys, and the screen which was very bright would remain stationary for days and days on end showing the same image quite often. I did see the image "etched" permanently on the screen - which was a bit strange. However I would stress that this was quite a while ago and LCD technology has moved on, and we were also talking about images that were stationary for days and days on end at maximum power.

    There is also the chance that the LCD panel might degrade due to excessive heat over time. This is why you want to make your projector run as cool as possible.

    So overall I wouldn't worry too much.
     

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