This test pattern is designed to provide a convenient means for measuring distortion in an optical system. The precise amount of distortion is determined from an array of precisely placed dots in a regular array. Such measurements can be used to correct for any distortion that occurs within the optical system. The pattern is available either as chrome on glass or white opal glass. Substrate dimensions are 5 inches square by 0.06 or 0.09 inch thick. Feature dimensions are listed in the table below. Dimensional tolerances of all features are ± 0.001 mm. Placement and center-to-center tolerance is ± 0.001 mm.
Dot Diameter (mm) Dot Spacing (mm)
Inner Zone: 0.200 0.400
2nd zone: 0.500 1.000
3rd zone: 1.000 2.000
Outer zone: 2.000 4.000