Patent ID: 11860007
Assignee: KABUSHIKI KAISHA YASKAWA DENKI
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An encoder comprising:
a scale being movable along a measurement direction and having a first absolute pattern, a second absolute pattern, and a third absolute pattern that are provided along the measurement direction; and
a sensor configured to measure the first absolute pattern, the second absolute pattern, and the third absolute pattern when the scale moves along the measurement direction, the sensor comprising:
a light source configured to emit light to the scale;
a first absolute light receiver configured to receive the light transmitted through or reflected on the first absolute pattern of the scale,
a second absolute light receiver provided opposite to the first absolute light receiver with respect to an optical axis of the light source and configured to receive the light transmitted through or reflected on the second absolute pattern;
a third absolute light receiver provided between the first absolute light receiver and the second absolute light receiver and configured to receive the light transmitted through or reflected on the third absolute pattern of the scale; and
a fourth absolute light receiver provided between the first absolute light receiver and the second absolute light receiver so that the light source is provided between the third absolute light receiver and the fourth absolute light receiver along the measurement direction, the fourth absolute light receiver being configured to receive the light transmitted through or reflected on the third absolute pattern of the scale.