The circular graduations of rotary
encoders are manufactured with the DIADUR process developed by
HEIDENHAIN. It produces a radial grating of opaque chromium lines with
very high edge definition. This high edge definition is a precondition
for a high quality of scanning signal.
The glass substrate permits the rotary encoders to operate at high
temperatures — as high as 100 °C (212 °F) on some models —
without any significant reduction of signal quality.
DIADUR circular graduations form the basis for the accuracy of HEIDENHAIN
rotary encoders.