Datum & Relational Metrology
In most optical lens applications, the alignment, positioning, and geometry of the lens are as critical as the surface form. If not aligned properly, a perfectly manufactured optical surface will perform poorly and can introduce errors not associated with part quality.
To facilitate proper alignment, many aspheric lenses will use additional geometric datums on the sample including flat annuli, conical interlocks, and precise outer diametersUtilizing ZYGO 3D metrology, many of these datums can be precisely characterized to ensure optimal lens system performance.
Typical applications include measurement of the flatness and height of annular datums, centration of optical surfaces and diameters, lens thickness, and roundness of conical interlocks. Datum analysis can lead to faster measurements and provide insight on errors caused by alignment vs. fabrication error.