Which is more susceptible to burn-in?

Discussion in 'Archived Threads 2001-2004' started by John_Berger, Aug 13, 2002.

  1. John_Berger

    John_Berger Cinematographer

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    Obviously, all TV sets are susceptible to burn-in when a section of the screen is bombarded with a constant image. However, which is more susceptible to burn-in - a regular tube-based TV or a projection TV - and why?
    The science lover in me is curious. [​IMG]
     
  2. Sumir B

    Sumir B Agent

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    From what I have read, RPTVs are much more susceptible to burn-in. I, however, cannot tell you why. Sorry[​IMG]
     
  3. SteveMo

    SteveMo Stunt Coordinator

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    The phosphors burn quicker because they get more hot than the single CRT design I think.

    Just guessing here.
     
  4. Kevin P

    Kevin P Screenwriter

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    Projection TVs and CRT projectors exhibit phosphor wear/"burn in" faster than direct view sets because the phosphors are driven harder on a projection set. On a direct view set you're looking directly at the phosphor coating on the front of the CRT. Therefore, the phosphors don't have to be driven very hard to produce a bright picture. Projection sets use three small CRTs (usually 7" diagonal each) attached to a stack of lenses that then project those three 7" images onto a much larger screen (40 to 80" diagonal). Therefore, in order to produce a watchable picture, the phosphors have to be driven much harder (brighter) than on a direct view set. Brighter translates to more wear and tear on the phosphors, and greater risk of burn-in in a shorter period of time.

    That's basically the gist of it. Still, with proper care, projection CRTs will give you many years of service.

    KJP
     
  5. Jack Briggs

    Jack Briggs Executive Producer

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    What Kevin said--except that the CRTs in most RPTVs are seven inches in diameter. [​IMG]
    You can, as you probably already know, squeeze the maximum lifespan out of an RPTV and a direct-view by taking the proper precautions against burn-in (i.e., white and black levels adjusted reasonably, etc.).
     
  6. John_Berger

    John_Berger Cinematographer

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    Ah. So, there is no actual phosphor on the screen itself. Interesting. That certainly does answer the question, and a few others.
    I guess that I should lower my brightness and contrast. [​IMG] That's still impressive that the picture quality can be that good from 7" CRTs.
    Thanks, guys!
     

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