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Text File  |  1997-10-29  |  368b  |  21 lines
  1.                                   ASPHERIC LENSES
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  3.  
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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
  8.  
  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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  16.  
  17. Q-value is also sometimes used.
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  19.   Q = -e
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  21.