Accuracy of movement tracking with a miniaturized second-generation Moiré device.

The availability of a Nanoform 600, a machine used in the contouring of optical components, with movement capabilities of 12.5 A, made it possible to determine the sensitivity, accuracy and movement tracking ability of a high-resolution measuring device using the principle of Moiré magnification. The Nanoform 600 was programmed to make a series of movements measured by the Moiré device. Comparison of the Moiré measurement with the programmed movements verified that the Moiré device is capable of reliably tracking movements as small as 0.05 microm. Increasing the rate of movement had little effect on linearity. Tracking movements over a 350 microm distance at rates of up to 340 microm per second resulted in a 0.23% error. Intentionally defocusing the Moiré signal did not appreciably affect sensitivity.