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

Claim 2:
3. An encoder comprising:
a scale being movable along a measurement direction and having a first absolute pattern and a second absolute pattern that are provided along the measurement direction;
a sensor configured to measure the first absolute pattern and the second 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, the first absolute light receiver comprising:
a plurality of first light receiving elements each configured to output a first absolute signal with a first phase when each of the plurality of first light receiving elements receives the light transmitted or reflected; and
a plurality of second light receiving elements each configured to output a first absolute signal with a second phase different from the first phase when each of the plurality of second light receiving elements receives the light transmitted or reflected, each of the plurality of first light receiving elements and each of the plurality of second light receiving elements being arranged alternately along the measurement direction; and

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, the second absolute light receiver comprising:
a plurality of third light receiving elements each configured to output a second absolute signal with the first phase when each of the plurality of third light receiving elements receives the light transmitted or reflected; and
a plurality of fourth light receiving elements each configured to output a second absolute signal with the second phase when each of the plurality of fourth light receiving elements receives the light transmitted or reflected, each of the plurality of third light receiving elements and each of the plurality of fourth light receiving elements being arranged alternately along the measurement direction.