Correction of localized shape errors on optical surfaces by altering the localized density of surface or near-surface layers
AssigneeThe Regents of the University of California
InventorsJohn S. Taylor, James A. Folta, Claude Montcalm
Life of this patent
Estimating the term…
Abstract
Figure errors are corrected on optical or other precision surfaces by changing the local density of material in a zone at or near the surface. Optical surface height is correlated with the localized density of the material within the same region. A change in the height of the optical surface can then be caused by a change in the localized density of the material at or near the surface.
Claims34
A method for correcting height errors on a substrate, comprising altering the density of a region selected from the group consisting of at least a portion of said substrate and at least a portion of a coating on said substrate, wherein an expansion or contraction of said region is produced such that the height of said region changes by an amount needed to mitigate surface height error.
An apparatus for mitigating a height error on a substrate, comprising:
- an interferometer for measuring the figure of a substrate with a surface that has a height error;
- and
- a mechanism for altering the thickness of a thin film coating, deposited over substantially all of said surface, to obtain a desired figure.
A method for altering height error on a substrate, comprising:
- depositing a thin film coating on the surface of a substrate that has a height error;
- measuring the figure of said surface;
- and
- altering the thickness of said thin film coating in the vicinity of said height error to obtain a desired figure.
An apparatus for altering a substrate height error, comprising:
- means for depositing a thin film coating on the surface of a substrate that has a height error;
- means for measuring the figure of said surface;
- and
- means for altering the thickness of said thin film coating in the vicinity of said height error to obtain a desired figure.
Dependencies are inferred from the claim text.