Charles R. Steinmetz

Displacement Measurement Repeatability In Tens Of Nanometers With Laser Interferometry

Recent advancements in Hewlett-Packard laser interferometers has made it possible to achieve displacement measurements with a repeatability in the tens of nanometers. This will be of key importance in achieving the submicron geometries in future integrated circuits. This measurement repeatability is achieved by the use of two new products that significantly reduce the major error components of the interferometer system. Before discussing the details of these products, an account is given on how to analyze the measurement repeatability of a laser interferometer system. Each component of the system repeatability budget are discussed. From this analysis it is observed that the most significant error components in this budget are due to atmospheric affects and the thermal drift of the optics. The affects of these errors have been reduced on the Hewlett-Packard system by the use of Wavelength Tracking Compensation and a new high stability interferometer.

Performance evaluation of laserdisplacement interferometry on a precision coordinate measuring machine

Abstract The trend toward tighter part tolerances from precision machine tools is placingincreased demands on position transducers on these machines. Improved accuracy, repeatability and resolution from the position transducers is required to match this trend. This paper describes a new performance modeling technique for laser interferometer systems.Each error affecting the measurement accuracy and repeatability is described in detail, along with the method to determine these performance measures. An example is given of this modeling technique for a precision coordinate measuring machine (CMM). Two new developments at Hewlett-Packard, Wavelength Tracking Compensation and the High Resolution Interferometer are also described that will help meet the future measurement requirements for precision machine tools.

Sub-Micron Displacement Measurement Repeatability On Precision Machine Tools With Laser Interferometry

Recent advancements in Hewlett-Packard laser interferometers has made it possible to achieve sub-micron displacement measurement repeatability in precision machine tool applications . This will be of key importance in cutting and measuring sub-micron toleranced parts in the future. This measurement repeatability is achieved by the use of two new products that significantly reduce the major error components of the interferometer system. Before discussing the details of these products, an account is given on how to analyze the measurement repeatability of a laser interferometer system. Each component of the system repeatability budget are discussed. From this analysis it is observed that the most significant error components in this budget are due to atmospheric affects and the thermal drift of the optics. The affects of these errors have been reduced on the Hewlett-Packard system by the use of Wavelength Tracking Compensation and a new high stability interferometer.