| 摘要 |
PROBLEM TO BE SOLVED: To provide an encoder capable of predicting in advance abnormality due to aging degradation. SOLUTION: The encoder 50' has a luminous element 2, a rotary disk 1 on which a pattern consisting of a light transmitting part and a light shielding part are provided, and a measuring part 10 consisting of a light reception element 3 for receiving the light from the luminous element 2 by way of the rotary disk 1 so that the reception signal according to the moving position of the rotary disk 1 is output. It also has a recording part 6 where a normal signal waveform of the reception signal output from the measuring part 10 is recorded as a recorded waveform in advance, a judging part 30' comparing the signal waveform of the reception signal output from the measuring part 10 and the recorded waveform, and judging abnormality of the luminous element 2 or the light reception element 3 in the case that a difference over a specific value is caused between them, and a correction circuit 9 for correcting the signal waveform of the reception signal output from the measuring part 10 so as to be nearly the same as the recorded waveform. COPYRIGHT: (C)2007,JPO&INPIT
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