Ultra Spherotronic®

Ultra Spherotronic
Ultra Spherotronic

The UltraSpherotronic®, the latest addition to our line of automatic spherometers, is the response to increased accuracy requirements in measurement of radii of curvature of optical components.

Key Features

  • Special linear encoder featuring the highest measurement accuracy worldwide
  • Under constant temperature conditions, the absolute measurement error of the linear encoder is less than 0.05 μm. The resolution is selectable: 0.01/0.05/0.1 μm.
  • high quality mechanical components andhighest stability
  • The probe is a ruby ball centered precisely to the encoder spindle. The use of a ruby ball probe excludes the accidental damage of valuable test plates during measurement.
  • The precise centering of the ruby ball is a key factor in obtaining the high repeatability of the UltraSpherotronic®.
  • Depending on the diameter of the spherometer ring used, a radius measurement accuracy of approx. 0.005% and a repeatability of 0.001% are achievable.
  • In order to further increase the ease of use, the probe travel is motorized. By simply pressing a button, the spindle of the linear encoder can be smoothly moved up and down.
  • Moreover, the contact force of the probe is always constant, this contributing to superior repeatability of the measurement results. To adapt to different applications, the requested contact force can be selected by simply switching a three-position selector.


  • Concave or convex optical components
  • Metal and glass balls
  • Polishing tools
  • When it comes to measure large aperture optics or radii longer than 1 m, the interferometers become impractical due to the high costs or impossibility of realizing the extra-long mechanical set up.
  • Using spherometers, the radius can be accurately measured before polishing, when it is still possible to correct the lenses. The accuracy of measurement is directly traceable to international standards, since TRIOPTICS spherometers are calibrated with (NIST and NPL) certified test plates.