Absolute position detection device and absolute position detection method

An absolute position detection method for use in an absolute position detection device comprising:

• comparing a first value with a second value, the absolute position detection device including:
• scale circuitry having a first member in which output pairs each for performing different outputs are disposed such that the different outputs are alternated, the scale circuitry being disposed on a mover or a stator;
• and sensor circuitry in which detection element groups each including a plurality of detection elements disposed at a first interval in a moving direction of the scale circuitry and configured to detect position correspondence information corresponding to a position of the first member are disposed by spacing a second interval in the moving direction of the scale circuitry, the first value corresponding to the position correspondence information detected by a first detection element of the detection elements, the second value corresponding to the position correspondence information detected by a second detection element adjacent to the first detection element in the detection element group including the first detection element;
• detecting based on a comparison result, a distortion boundary position that is a position at which intensity distribution of the outputs starts to deviate in the moving direction;
• and
• when setting either the first detection element or the second detection element used for detection of the distortion boundary position as a reference detection element, based on first element coordinates that are a position of the reference detection element in the sensor circuitry, second element coordinates that are a position, in the sensor circuitry, of a third detection element of the detection elements included in the detection element group including the reference detection element, the first interval, a third interval that is a length of the output pairs in the moving direction, and a third value corresponding to the position correspondence information detected by the third detection element, calculating a position of the third detection element with respect to an end position that is a position of an end of the first member in the moving direction, and calculating a positional relationship between the mover and the stator based on the position of the third detection element with respect to the end position and a length of the first member in the moving direction.