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Process for fabricating multi-discrete-phase fresnel lenses

  • US 5,278,028 A
  • Filed: 11/25/1991
  • Issued: 01/11/1994
  • Est. Priority Date: 12/26/1989
  • Status: Expired due to Term
First Claim
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1. A method for fabricating a multi-discrete-phase Fresnel lens having a predetermined radial phase profile that is composed of a plurality of discrete phase steps, said method comprising the steps ofdepositing a first reactive ion etch resistant overcoat of predetermined thickness on an essentially flat surface of a substrate;

  • depositing a layer of etchable material of predetermined thickness on said first overcoat;

    depositing a second reactive ion etch resistant overcoat on said etchable material;

    photolithographically patterning said second overcoat in conformity with said radial phase profile for selectively exposing radially bounded portions of said etchable material;

    reactive ion etching the exposed portions of said etchable material to expose underlying portions of said first overcoat,removing the exposed portions of said first overcoat and the patterned second overcoat for profiling said lens in accordance with at least a first and a second of said phase steps.

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