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How do you convert an LED infrared light source into visible light?

Discussion in 'Electrical Engineering' started by Beachcomber, Nov 26, 2006.

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  1. Beachcomber

    Beachcomber Guest

    Does anyone know what material(s) fluoresce under infrared light? For
    those that are familiar with them, there are small plastic cards used
    by TV technicians that will glow visibly when an infrared TV remote
    control is pointed to a spot on the card in close proximity. I am
    looking for the specific mineral or manufactured material that does

    I am aware that you can point these infrared controller sources at a
    small inexpensive TV camera and more, likely than not, you will be
    able to see the LED "light" in a video image of the signal.

    Note that this is not the same as ultraviolet fluorescence, which, of
    course, is much more common.

  2. Al

    Al Guest

    You might try the sci.optics newsgroup. They jaw about stuff like this
    all the time. They are heavy on the science.

  3. JohnR66

    JohnR66 Guest

    Radio Shack used to sell a little card that would glow red when held in the
    IR beam of a remote. Edmund scientific may sell this material now.
  4. John Gilmer

    John Gilmer Guest

    Didn't you have to "charge" the card first by exposing it to UV light?

    The IR light would "trip" electrons/holes that were boosted to a higher
    state and cause then to fall to some intermediate state and emitting a
    photon in the visible light range.
  5. Beachcomber

    Beachcomber Guest

    No, I have one of the cards. It lights up pretty much instantly when
    exposed to infrared light (such as from a remote control). It tells
    the technician that the IR diode is producing at least some IR energy.

    Maybe you are thinking of those glow in the dark devices or coating
    materials, which, as far as I know, charge up under visible light.

    I've never seen one of these that worked well (stayed on and glowing
    all night after a full charge). When I was a kid, radioactive Radium
    glow-in-the-dark watches were common. They would glow in complete
    darkness but they supposedly killed a lot of workers in the
    manufacturing plant.

    What I am looking for is the mineral or rare-earch material that will
    light up in the presence of infrared. Something commonly available
    would be nice, but it seems to be a trade secret.

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