Abstract: The present invention provides an apparatus for supporting a workpiece in a precision processing system. The apparatus includes a plurality of workpiece contact elements for supporting the workpiece substantially in a plane, and a compliant stiction support for reducing workpiece vibration. The workpiece supporting apparatus can include a base member connected to the workpiece contact elements and to the compliant stiction support. The complaint stiction support can include a slider assembly for contacting the workpiece. The slider assembly is in sliding, frictional connection with the base member. The compliant stiction support can further include a workpiece contact spring element for forcing the slider assembly into contact with the workpiece. The compliant stiction support can further include a stiction spring element. The stiction spring element is in contact with the slider element. The stiction spring element forces the slider element into frictional contact with the base member.

Abstract: A refractometer provides a reference path coaxial with a measurement path and thereby simplifies construction by reducing the number of parts and simplifies maintenance by halving the number of optical axes to be aligned. The refractometer includes a reference projector for projecting a reference pattern on a reference pattern position on a detector during a reference interval, a site-selector for selecting a measurement site on an optical system, and a measurement projector for projecting a measurement pattern through this selected measurement site and onto a measurement pattern position on the detector during a measurement interval. The reference projector, the site selector, and the measurement projector are all aligned along the same optical axis. In the case in which the optical system is a human eye, the designated site in typically a site on the cornea and the detector is the retina of the eye.