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Text File  |  1997-10-28  |  406b  |  21 lines
  1.                                ASPHERIC LENSES
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  5. Aspheric lenses are also specified in another way using what is called the p-value.  Where:
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  7.      p = 1 - e
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  9. Relationship of p-value to surface shape:
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  11.     p=1.0      spherical surface
  12.     1<p>0     elliptical surface
  13.     p=0         parabolic surface
  14.     p<0         hyperbolic surface
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  17. Q-value is also sometimes used.
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  19.      Q = -e
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