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US 4,376,161 AGranted
Encoder disc and method of manufacture
AssigneeDynamics Research Corporation
InventorLuke R. Volpe
Life of this patent
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Abstract
An encoder disc is provided with a pattern and a central aperture having a straight uniform interior side wall, with the aperture being precisely located relative to the pattern.
Claims9
A method of making an encoder disc comprising the steps of:
- positioning a transparent master disc having an opaque pattern thereon and a central spindle over an electrically conductive master platten having a photoresist layer thereon and an aperture through the photoresist layer and the platten, such that the spindle protrudes into the aperture;
- exposing the photoresist through the master disc;
- removing the master disc;
- developing the photoresist;
- locating a non-conductive straight-sided plug in the aperture;
- electroforming a layer over the platten;
- and,
- stripping the electroformed layer from the platten.
5 more elements
Dependencies are inferred from the claim text.