A Visible Laser Interferometer for Air Bearing Separation Measurement to Submicron Accuracy

Hydrodynamic lubrication problems can be investigated using a visible laser interferometer, as presented here, to obtain both steady-state and dynamic film thickness characteristics. The special case of a self-acting air bearing slider system used in present day computer peripheral equipment is investigated. Measurement accuracies of better than 0.005 μm can be achieved for both steady state and dynamic measurements. This technique should be especially valuable for low spacing, self-acting lubrication problems and can surpass the accuracies of presently used interferometric, capacitive, and inductive methods. A mathematical treatment of the optical interference phenomena as applicable to a hydrodynamic lubrication film is developed. Experimental results are presented and discussed.