An imaging displacement sensor with nanometer accuracy

Abstract

An imaging displacement sensor (IDS) has been developed that can measure the displacement with an accuracy of 30 nm in 0.03 s with the precision improving to 1 nm for averaging times of 100 s. The IDS consists simply of a light emitting diode (LED) pinhole collimator and a charge-coupled device (CCD) camera chip. The position accuracy is better than 0.05% over the few mm CCD size with deviation from linearity <140 nm. All six degrees of freedom (DoF), three translations and three angles, can be measured with the same accuracy by combining multiple IDS with different collimator beam orientations and knowing the nominal separation between the collimators and CCDs.

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