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[optics] How to transport light/image in narrow tube

  1. Jan 23, 2016 #1
    Hello there!
    I'm new on the forum and english is not my first language.
    I'm working on an art project and I wonder if there's any mean by which I can transport the light from an illuminated scene across a small tube (let say not larger than 5 cm in diameter) and over some distance (let say 2 meters) and restitute that light on a large mirror.
    Please see my image below.
    Thank you!

  2. jcsd
  3. Jan 23, 2016 #2


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    Staff: Mentor

    Welcome to the PF.

    Are you familiar with fiber optic bundles? I'm not sure you will get a very bright final image, however...


  4. Jan 23, 2016 #3
    Thank you. I've read about those, I think the final image would be pixelated. I need the final image to be perfect, as if a direct reflexion on a mirror.
    I've just read about rod lenses, I think it's my best bet for the moment. Are you familiar with those?
    My other question would be, how to "expand" the final image on a large surface (on a mirror, to preserve 3D ?).
  5. Jan 25, 2016 #4


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    Gold Member

    How far do you want to transmit this image? I.e. how long is the rod?

    If the distance is short I would probably get two cheap, low powered telescopes and put them eyepiece to eyepiece. The beam in between the eyepieces should be collimated and therefore perform the same job as your rod.

    Unless your system is perfect and the resultant image is the same size as the original you will loose brightness.

    However, far simpler would be a digital camera one end and a projector the other.
  6. Jan 26, 2016 #5
    Thanks Bandit.
    The rod could measure between 300 and 100mm (the longer the better).
    I am right to think that collimated light wouldn't preserve parallax? I.e. when I look in a mirror, the reflection appears in 3D. If light is collimated before reaching the final mirror, would it still appears in 3D?
  7. Jan 26, 2016 #6


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    Can you use a webcam and mini projector?

    The internet is just a series of tubes anyway!

  8. Jan 26, 2016 #7

    Andy Resnick

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    The only real way to do as you envision is to fill the tube with a bunch of relay lenses, and since you are not a lens designer this will result in a horribly aberrated final image.
  9. Jan 26, 2016 #8
    Thanks for your input Andy. So rod lenses couldn't work? I could buy a borescope and use the middle section.

  10. Jan 27, 2016 #9

    Andy Resnick

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    Sure, a borescope/endoscope/etc could work, but modern ones simply put a small camera at the end. Old-timey ones, AFAIK, don't extend much beyond a foot or so.
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