Kiyohara Optics, Japan

The HEXTEK lightweight 480mm x 135mm reference flat was purchased by the Minolta Corporation as a calibration optic. Zygo interferogram shows an overall flatness of better than 1/10-wave peak-to-valley and 1/55-wave rms @ 632nm.

This HEXTEK lightweight 340 mm flat is used as a calibration optic.