Radius
CONTROLS: Radius of curvature of a spherical surface at minimum RMS irregularity, spherical power of a plano surface or vertex radius of asphere
RELATED TERMS: Radius of Curvature, Power
UNITS: Linear units for radius, wavelengths or half-wavelengths (fringes) for power
SPECIFICATIONS MUST CONTAIN: Nominal radius value and fringes of power over an aperture or a nominal radius value with linear or percent deviation from nominal over an aperture
OPTIMAX PREFERRED SPECIFICATION: Radius deviation for spherical and aspherical, fringes power for plano
REASONS: Radius is directly measured on an interferometer for radii with interferometric coverage or with a profilometer for aspheres and long spherical radii without interferometric coverage.
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Lens Tolerancing & Inspection Technical Paper
Tolerancing, Specifying, and Measuring Spherical Radius
Two main paths for tolerancing spherical radii are power tolerance and linear radius tolerance.
Both measure change relative to a nominal value, but the metrology used is the key difference.
