OPTICAL ENCODER Russian patent published in 2012 - IPC H03M13/35 G01D5/347 

FIELD: physics.

SUBSTANCE: optical encoder, wherein distribution of the transmission coefficient or distribution of the reflection coefficient, provided in scale track on the displacement scale, has a first modulation period and a second modulation period in the direction of displacement of the scale; an array of photodetector elements is intended to detect a first group of signals which includes two phase signals which are antiphase with respect to each other during the first modulation period and a second group of signals which includes two phase signals which are antiphase with respect to each other during the second modulation period, wherein first positional information during the first modulation period is determined from the first group of signals, and second positional information during the second modulation period is determined from the second group of signals, the second modulation period being an odd-multiple of the first modulation period.

EFFECT: reduced error component of the detected waveform and determining positional information with high accuracy.

5 cl, 14 dwg