Sunglasses with hi-index lens and AR coating?

Discussion in 'Glasses' started by JustLikeToSay, Apr 5, 2006.

  1. Hi all:

    I'm not sure if this group is the right place to ask about it. If I'm
    posting on the wrong group, please accept my apology and would
    appreciate it if you can guide me to the right group for the question.

    My question is: I have a pair of sun-glasses with high-index lenses.
    Everything's fine except that when the sun is shining on my face at a
    high angle from the front, I can see my the reflection of my eyes and
    face on the lenses. I've heard that high-index lens can do well with AR
    coating. I'm wondering if sunglasses with high-index lens need AR
    coating (some say it doesn't). Since it's expensive to get the coating,
    I'd like to know if I do go get the coating, will the
    seeing-my-face-in-my-glasses problem go away?

    If the lenses were polarized polycarbonate lenses, will that problem be
    there?

    Thanks in advance for your response.


    Charles
     
    JustLikeToSay, Apr 5, 2006
    #1
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  2. Sounds like you need an ar coating on the inside only. Often done on
    high quality sunglasses.

    w.stacy, o.d.
     
    William Stacy, Apr 5, 2006
    #2
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  3. JustLikeToSay

    Salmon Egg Guest

    In principle, it is easier to design AR coatings for high index glass, circa
    n=1.9 than for lower index. High index glass will reflect more, almost 10%
    per uncoated surface for n=1.9. That, by the way is a very high index for
    ordinary glass. Until after WWII most people were able to survive uncoated
    glasses quite well.

    Bill
    -- Ferme le Bush
     
    Salmon Egg, Apr 6, 2006
    #3
  4. JustLikeToSay

    Quick Guest

    Wasn't that because they weren't able to polish
    them enough to reflect back then? -:)

    -Quick
     
    Quick, Apr 6, 2006
    #4
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