Length Bar Interferometer

The LBI1.5 was designed by the UK NPL to meet the requirement for calibrating longer type Length Standards at a Primary level and with the best possible Measurement Uncertainty.  Long Series Gage Blocks and Length Bars in lengths up to 1.5 meters (60") can be accommodated. 

The LBI1.5 uses the same FLaP software as used on the GBI300 Gage Block Interferometer. 



  • Three frequency stabilised laser light sources
  • Phase-stepping optical system for high precision length measurement and detailed analysis of Length Standard surface geometry
  • Horizontal support of the Length Standard meets specification requirements
  • Insulating and temperature controlled enclosure of the optical system
  • Full and automatic measurement and compensation for ambient conditions
  • Integrated and rapid Flatness and Variation in Length measurement
  • Automatic calculation of Length measurement results in metric or inch units
  • Flexible image processing software for the measurement of rectangular, square and round Length Standards
  • Hexagon offer Instrument calibration and a Platen refurbishment services if required
Measurement Capacity Length Standards from 100 mm to 1500 mm (4" to 60") in length 
Length Standard types Rectangular, Square and Round Gauges made from Steel, Ceramic, Tungsten Carbide, Chrome Carbide etc.
Length Measurement Uncertainty A Measurement Uncertainty of ± √(492 + (87 x L)2) nanometres (“L” in meters) is possible  when the LBI1.5 is located within the correct environment
 Features measured Gauge Length, Flatness, and Variation in Length, of the Length Standard
 Measurement Results Displayed in Metric or Inch as appropriate
 Software FLaP for Windows™ validated by NPL for precision of computation