High index material technology?

Discussion in 'Optometry Archives' started by Guest, Aug 13, 2005.

  1. Guest

    Guest Guest

    Optical glasses were once classified as light (crown) and dense (flint)
    glass. The denser (mass per volume) glasses had higher indexes than the
    light glasses. Except for some special formulations, expensive rare earth
    glasses for example, it was difficult to get lighter lenses of the same
    optical power by increasing the index. Is that still true? Are such glasses
    used for eyeglasses?

    Does the same relationship between density and index hold for plastic? Where
    can I get such data on plastic? What is the mechanism that allows higher
    index without a corresponding increase in density? In glass, it usually
    depends upon the density of electrons that are excited by light.

    Bill
     
    Guest, Aug 13, 2005
    #1
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  2. Guest

    BC Guest

    Virtually all of the dense flint glasses based on lead have been
    replaced with much lighter titanium-based glasses having identical
    refractive index and Abbe number. The main motivation for doing this
    was to avoid lead poisoning, but the lower density is certainly a good
    thing for most applications.

    Brian
     
    BC, Aug 16, 2005
    #2
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  3. Check out Optics & Photonics News, August 2004:

    http://www.osa-opn.org/abstract.cfm?URI=OPN-15-8-36

    Johannes
     
    Johannes Swartling, Aug 17, 2005
    #3
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