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B Variable focal length TV / screen

  1. Oct 25, 2016 #1
    Recently I have had a lot of eye strain from excessive computer use. The problem is because your eye lenses re stuck in a fixed position.

    I wanted to know if it would be possible to make a screen that is 1m away look like it is 4m away for example. Would it be possible by making the screen out of focus somehow? Is it possible?
  2. jcsd
  3. Oct 25, 2016 #2


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    Staff: Mentor

    Interesting question. The first thought that comes to mind would be to equip each pixel with a lens that projects a near-collimated beam of light toward the user's eyes. This should make the screen appear much further away and also keep each pixel from being blurred into the others surrounding it. Unfortunately this would greatly limit the angle at which the screen can be viewed.
  4. Oct 26, 2016 #3
    You can do this already by looking through a telescope the wrong way for example. I'm still trying to think how it would "look" if each pixel had a lens / how you would have to set this up..

    Regarding the viewing angle, you could use liquid lenses that can be adjusted accordingly by using a camera that tracks your eye position.

    Another interesting idea could be to use video that has been recorded with a light-field camera, so tracking where you look on the screen will also bring into focus that area. Now that would be interesting to see, maybe this is something that can also be used in VR (but I don't know if 360 degree light-field cameras exist).
  5. Oct 26, 2016 #4


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    Science Advisor

    Look up head-up-displays (no pun intended). They are usually projecting an image at infinity.
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