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Thread: plz help me

  1. #1
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    plz help me

    i am an optometrist and i need to any link that talks about Aspheric lens
    thanks

  2. #2
    What's up? drk's Avatar
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    Perhaps it was Harry who posted this:

    What is an Aspheric in simple terms ?
    --------------------------------------------------------------------------------
    Curved surfaces follow the geometric formula for conic sections:
    Y(squared) = 2(R)(X) + (P)X(squared)
    The shape of the conic section depends on the value of P, where R is the radius of curvature of the surface at the vertex.
    Values of P
    a) P > 1 you obtain an oblate ellipse
    b) P = 1 you obtain a circle
    c) 0<P<1 you obtain an prolate ellispe
    d) P = 0 you obtain a parabola
    e) P < 0 you obtain a hyperbola
    If you take this formula and rotate through the Z axis you will obtain a surface that falls away from the apex at a constant rate. The easiest
    surface to generate was P = 1 a circle, which when rotated through
    Z gives a simple spherical surface the simplest to manufacture. No
    all aspheric surfaces are not the same - It depends on what value of P
    each manufacturer picks.

  3. #3
    ATO Member HarryChiling's Avatar
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    Sounds like it might have been me, here is a link for a more patient oriented explanation.

    http://www.eyetopics.com/articles/15...-Aspheric.html
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  4. #4
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    thanks you
    but i want another links if any body can help me

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