| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an encoder that can stably detect an origin synchronized with an A-phase signal or a B-phase signal with small dependency on a scanning direction and is used for detecting displacement. <P>SOLUTION: The encoder includes: detection parts 22 and 32 for projecting light emitted from light emitting parts 21 and 31 on a scale 4 to detect a diffraction pattern of the reflected light; and a signal processing circuit for processing the signals of the detection parts 22 and 32 as encoder signals. Each of the encoder signals is composed of an A-phase signal and a B-phase signal which are position signals in which the phases are shifted to each other by 90 degrees to show a moving direction and a Z-phase signal for detecting an origin position when a power source is turned on again and the like after turning off the power source. Of the scale 4, a solid pattern formed by two regions: a light reflection region and a light transmission region is used for a Z-phase scale 41 forming the Z-phase signal, and the Z-phase signal is a pulsed signal which can be obtained by digitizing a Z-phase output signal formed from the Z-phase scale 41 for detecting displacement of an object from a relative moving amount between the Z-phase signal and the scale 4. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
