End Standards Measurement

End standards measurement is a fundamental aspect of geometric metrology. Extensive research has been conducted on the high-precision measurement of gauge blocks, gauge block pairs, and step height gauges both domestically and internationally. Gauge block measurement methods are divided into comparison and absolute interference methods. The comparison method involves a high-precision gauge block comparator, utilizing a probe with high positioning repeatability and interference comparison technology, achieving a measurement uncertainty of 0.04 μm+0.4×10⁻⁶L. The absolute interferometry method discusses the principle and historical development of gauge block absolute interferometry in China. This method encompasses both single-ended and double-ended gauge block interferometry techniques, leading to the development of single-ended phase shifting and double-ended phase shifting gauge block interferometers. These devices attain a measurement uncertainty of 15 nm+0.15×10⁻⁶L. Research on phase shifting interferometers laid the foundation for gauge block pair and step height gauge measurements. High precision measurement of gauge block pairs was achieved under specified conditions determined through uncertainty analysis and experimental validation, with measurement uncertainty not exceeding 10 nm. Single-ended phase shifting interferometers enable high-precision measurement of step height gauges, with center height measurement uncertainty reaching (0.01～0.1) µm. To meet ultra-high precision length measurement needs, research on ultra-high precision interferometry technology is identified as the future trend in end standards measurement. Existing single-ended and double-ended phase shifting interferometry technologies pave the way for developing ultra-high precision interferometers, thereby achieving nanoscale measurement uncertainty in end standards measurement.