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Thread: Optics help

  1. #1 Optics help 
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    Hi troops

    I’m looking for insight with a problem I’m having.

    The task at hand is how to make my own set of optical lenses that would allow the user/wearer to focus on a screen that will be placed around 50 to 70mm from the users eyes. (when I say make, I don’t mean manufacture the lenses, I just mean assemble into the right config etc)

    I know it can be done, for example the set of lenses used in an older camcorder, the viewfinder was no longer than that kind of distance yet you could easily focus on the image.

    I have no optical background so I’m clueless with this stuff.

    The end goal is to allow the eye to focus far off like in a viewfinder but have the image rendered at close range.

    Is there some webby that can help me out with this kind of optic production?

    I’m from the UK and would rather deal with a UK distributor if possible.
    I am contacting a bunch of suppliers tomorrow, just thought you smart peeps might have a wicked solution that I am completely overlooking

    Okay, thanks in advance for any help guys

    Lime


    Last edited by Lime; May 24th, 2012 at 02:18 PM.
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  3. #2  
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    It sounds like you are describing a very strong pair of reading glasses. Reading glasses are rated in diopters, where the diopter is 1 meter divided by the focal length. So a 2 diopter lens focuses at 1/2 meter. Since you want to focus at about .07 meters the diopter rating would be about 14 or 15. The strongest reading glasses you can buy off the shelf are 3 diopters (1/3 meter).

    People who have had their lenses removed due to cataracts, and who do not have implanted lenses, sometimes wear very thick "coke bottle lens" glasses. Maybe you can find a pair of those. I don't know what the diopter rating of such lenses might be.


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  4. #3  
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    Thanks for the feedback..

    I did read somewhere that these camcorder viewfinders allowed the eye to focus on infinity or something like that, if you get my meaning

    I'm hoping that one of the manufacturers I speak to tomorrow can put me on the right path. Might have to go get a free eye test and start quizzing the optician lol
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  5. #4  
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    they are called binoculars
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  6. #5  
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    Quote Originally Posted by Lime View Post
    Thanks for the feedback..

    I did read somewhere that these camcorder viewfinders allowed the eye to focus on infinity or something like that, if you get my meaning
    Yes, I do get your meaning. That's what reading glasses do, too. They allow you to focus on something close without using the focusing power of the crystalline lens in your eye. Those of us older folk who have lost any flexibility in our crystalline lens, cannot focus close at all. Our eyes are permanently focused at infinity, or if we are nearsighted, at some intermediate distance.
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  7. #6  
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    Ok that's fantastic, I know where to start now.

    Thank you very much Harold.
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