TiBook: Dim LCD after waking from sleep

Discussion in 'Mac Help/Tips' started by Schiffi, Jul 13, 2003.

  1. Schiffi macrumors 6502a


    May 22, 2003
    After waking my TiBook up after sleep the monitor appears dim, but slowly becomes bright. Is this normal behavior?
  2. WinterMute Moderator emeritus


    Jan 19, 2003
    London, England
    My old 400 tiBook, used to do that, it did it a little more theolder it got, the 17 does it a little, but with the auto-light adjuster it's always a little difficult to tell.

    I'd say it was pretty normal.
  3. Kwyjibo macrumors 68040


    Nov 5, 2002
    I don't have this problem, sometimes the backlight goes out tho, that may be whats happening.
  4. King Cobra macrumors 603

    Mar 2, 2002
    I don't think this is odd behavior. My ref. Apple 15 inch LCD does this all the time.

    It's a nice feeling to know your monitor doesn't try to blind you after being in a dark room for a while. :D
  5. patrick0brien macrumors 68040


    Oct 24, 2002
    The West Loop

    My 12PB has done a little of this since day one. Along with every laptop I've owned. I believe this has to do with the phosphorus in the backlight needing to reach a critical excitement mass - samer thing with CRT's needing it. Streetlights have the same effect, though they're argon or mercury vapor.

    It's normal.
  6. Daveman Deluxe macrumors 68000

    Daveman Deluxe

    Jun 17, 2003
    Corvallis, Oregon
    Pat's right on the money. To create the chemical reaction that releases light from the phosphors in the backlight tubes, a certain specific number of free electrons are needed which come from the cathode in the tube.

    When the current is first applied to the cathode, it takes some time to get up to that level. When it does, it often overshoots the mark and then quickly stabilizes at a lower level. This appears as a brief initial flash of light that quickly dims.

    At that point there are enough free electrons in the tube to sustain the reaction that generates light, but in the first few seconds and even minutes of the reaction, there are still phosphors that can accept an electron that are not being filled. You might say that there is a glut of electrons. Eventually, the supply and demand sides of the curve meet and you get the final result.

    The same thing happens with CRTs, that's why graphics designers are supposed to turn their monitors on at least fifteen minutes before they start working, for color-matching purposes.

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