Rotation angle sensor, angle signal calculation method and non-transitory computer readable medium

An angle signal calculation method comprising:

• acquiring a magnetic field in a first direction varying by a rotation of a magnet disposed to be rotatable around a rotational axis and polarized into at least two poles in a direction perpendicular to the rotational axis, as an output of a first magnetic detection element;
• acquiring a magnetic field in the first direction as an output of a second magnetic detection element disposed at a position different from a position of the first magnetic detection element and at a position where a first disposition angle, relative to the first magnetic detection element, is greater than 0 degrees and less than 90 degrees, the first disposition angle being, in plan view, a smaller angle of angles formed by a line segment connecting the first magnetic detection element and the rotational axis and a line segment connecting the second magnetic detection element and the rotational axis, or being, in cross-sectional view, a smaller angle of angles formed by a line segment connecting the first magnetic detection element and a center of the magnet and a line segment connecting the second magnetic detection element and the center;
• acquiring magnetic field in a second direction different from the first direction as an output of a third magnetic detection element and an output of a fourth magnetic detection element, the third magnetic detection element and the fourth magnetic detection element being disposed at positions different from the position of the first magnetic detection element;
• outputting a first magnetic field calculation signal, based on the output of the first magnetic detection element and the output of the second magnetic detection element;
• outputting a second magnetic field calculation signal different in phase from the first magnetic field calculation signal, based on the output of the third magnetic detection element and the output of the fourth magnetic detection element;
• and
• outputting an angle signal indicative of a rotation angle of the magnet, based on the first magnetic field calculation signal and the second magnetic field calculation signal.

A non-transitory computer readable medium having stored thereon a program causing a computer to execute:

• acquiring a magnetic field in a first direction varying by a rotation of a magnet disposed to be rotatable around a rotational axis and polarized into at least two poles in a direction perpendicular to the rotational axis, as an output of a first magnetic detection element;
• acquiring a magnetic field in the first direction as an output of a second magnetic detection element disposed at a position different from a position of the first magnetic detection element and at a position where a first disposition angle, relative to the first magnetic detection element, is greater than 0 degrees and less than 90 degrees, the first disposition angle being, in plan view, a smaller angle of angles formed by a line segment connecting the first magnetic detection element and the rotational axis and a line segment connecting the second magnetic detection element and the rotational axis, or being, in cross-sectional view, a smaller angle of angles formed by a line segment connecting the first magnetic detection element and a center of the magnet and a line segment connecting the second magnetic detection element and the center;
• acquiring magnetic field in a second direction different from the first direction as an output of a third magnetic detection element and an output of a fourth magnetic detection element, the third magnetic detection element and the fourth magnetic detection element being disposed at positions different from the position of the first magnetic detection element;
• outputting a first magnetic field calculation signal, based on the output of the first magnetic detection element and the output of the second magnetic detection element;
• outputting a second magnetic field calculation signal different in phase from the first magnetic field calculation signal, based on the output of the third magnetic detection element and the output of the fourth magnetic detection element;
• and
• outputting an angle signal indicative of a rotation angle of the magnet, based on the first magnetic field calculation signal and the second magnetic field calculation signal.