The Korea Research Institute of Standards and Science (KRISS) announced on Jan. 21 that a research team led by Dr. Eom Tae-bong developed a precision calibration system capable of improving the measurement accuracy of laser interferometers.
A laser interferometer is a device for precision length measurements based on the interference characteristics of lasers stabilized to have a constant wavelength. The most advanced form of measuring instrument in the segment of the industry, it is in wide use as a displacement measurement sensor for ultra-precision systems such as semiconductor lithography equipment.
Existing laser interferometers, in the meantime, are prone to length measurement errors because the laser wavelength varies depending on environmental factors like temperature, pressure and humidity. The team, however, came up with a laser interferometer calibration system with built-in advanced environmental sensors at this time. This system compares values measured by the interferometer of the institute and existing interferometers to each other and shows the errors. For example, a standard interferometer and another one that needs to be calibrated are installed on moving devices with ranges of movement of 2 m and 50 m, and then the distance values measured by the respective interferometers are compared to each other while the distances of the moving devices are altered.
“This new device can improve length measurement accuracy by about 10-fold,” Dr. Eom explained, adding, “It will contribute to production efficiency and safety in various industrial fields.”