ENCODER

摘要

An encoder has an optical measuring part establishing a vernier relationship between a code plate (1) and a line sensor (5), and counters (12,17) for obtaining a coarse reading from time serial output signals of the line sensor (5) and a fine reading from the vernier relationship. Correction data including a change component in a magnification of a lens system (4) is obtained from a counter (23). The correction data and the fne reading are supplied to a converting circuit (13a) to provide a corrected fine reading.