Magnetic sensor and magnetic sensor system
A magnetic sensor includes a first MR element disposed on an inclined surface and configured to generate a first detection signal, a second MR element disposed on an inclined surface and configured to generate a second detection signal, and a conversion section configured to convert the first detection signal and the second detection signal into a first corrected signal and a second corrected signal, respectively. The conversion section is configured to change an amplitude of at least either one of the first and second detection signals to make a ratio of the amplitude of the second corrected signal to the amplitude of the first corrected signal different from a ratio of the amplitude of the second detection signal to the amplitude of the first detection signal.
1 . A magnetic sensor comprising:
a support member having at least one inclined surface inclined relative to a reference plane;
a first magnetic detection element disposed on the at least one inclined surface and configured to detect a target magnetic field and generate a first detection signal, the first detection signal having a first amplitude with a maximum value and a minimum value;
a second magnetic detection element disposed on the at least one inclined surface and configured to detect the target magnetic field and generate a second detection signal having a phase different from that of the first detection signal, the second detection signal having a second amplitude with a maximum value and a minimum value; and
a conversion section,
wherein the maximum value and the minimum value of the first detection signal are equal to the maximum value and the minimum value of the second detection signal, and
the conversion section is configured to convert the first detection signal and the second detection signal into a first corrected signal and a second corrected signal, respectively, the conversion section being configured to change at least either one of the first amplitude of the first detection signal and the second amplitude of the second detection signal to make a ratio of a second corrected amplitude of the second corrected signal to a first corrected amplitude of the first corrected signal different from a ratio of the second amplitude of the second detection signal to the first amplitude of the first detection signal, the first corrected amplitude being a half of a difference between a maximum value and a minimum value of the first corrected signal, the second corrected amplitude being a half of a difference between a maximum value and a minimum value of the second corrected signal.
2 . The magnetic sensor according to claim 1 , wherein the conversion section is configured so that the ratio of the second corrected amplitude of the second corrected signal to the first corrected amplitude of the first corrected signal is a value other than 1.
3 . The magnetic sensor according to claim 2 , wherein:
the first detection signal is a signal leading the second detection signal in phase; and
the conversion section is configured so that the ratio of the second corrected amplitude of the second corrected signal to the first corrected amplitude of the first corrected signal does not fall within a range of 1 or less.
4 . The magnetic sensor according to claim 1 , wherein an angle that the at least one inclined surface forms with the reference plane is in a range of 10° or more and 45° or less.
5 . The magnetic sensor according to claim 1 , wherein the first magnetic detection element and the second magnetic detection element each have a circular planar shape.
6 . The magnetic sensor according to claim 1 , further comprising:
a power supply port;
a ground port;
a first output port;
a second output port;
a first resistor section provided between the power supply port and the first output port;
a second resistor section provided between the power supply port and the second output port;
a third resistor section provided between the ground port and the first output port; and
a fourth resistor section provided between the ground port and the second output port, wherein
either one of the first and third resistor sections includes the first magnetic detection element,
another of the first and third resistor sections includes a third magnetic detection element disposed on the at least one inclined surface and configured to detect the target magnetic field and generate the first detection signal in cooperation with the first magnetic detection element,
either one of the second and fourth resistor sections includes the second magnetic detection element, and
another of the second and fourth resistor sections includes a fourth magnetic detection element disposed on the at least one inclined surface and configured to detect the target magnetic field and generate the second detection signal in cooperation with the second magnetic detection element.
7 . The magnetic sensor according to claim 1 , wherein:
each of the first and second magnetic detection elements is a magnetoresistive element;
the magnetoresistive element includes a magnetization pinned layer having a first magnetization whose direction is fixed, a free layer having a second magnetization whose direction is variable depending on the target magnetic field, and a gap layer located between the magnetization pinned layer and the free layer;
a direction of the first magnetization of the magnetization pinned layer of the first magnetic detection element and a direction of the first magnetization of the magnetization pinned layer of the second magnetic detection element intersect each other; and
either one of the directions of the first magnetizations of the magnetization pinned layers of the first and second magnetic detection elements intersects the reference plane.
8 . The magnetic sensor according to claim 1 , further comprising a processor configured to generate a detection value having a correspondence with an angle to be detected using the first corrected signal and the second corrected signal.
9 . The magnetic sensor according to claim 8 , wherein the processor includes the conversion section.
10 . The magnetic sensor according to claim 1 , wherein the conversion section includes a resistor electrically connected to the first magnetic detection element or the second magnetic detection element.
11 . The magnetic sensor according to claim 1 , wherein:
the at least one inclined surface includes a first inclined surface and a second inclined surface;
the first magnetic detection element is disposed on the first inclined surface; and
the second magnetic detection element is disposed on the second inclined surface.
12 . A magnetic sensor system comprising:
the magnetic sensor according to claim 1 ; and
a magnetic field generator that generates the target magnetic field.
13 . The magnetic sensor system according to claim 12 , wherein the magnetic sensor is opposed to an outer periphery of the magnetic field generator.
14 . The magnetic sensor system according to claim 13 , wherein the magnetic sensor and the magnetic field generator are configured so that a direction of the target magnetic field at a predetermined position rotates as a position of the magnetic field generator relative to the magnetic sensor changes.
15 . A magnetic sensor comprising:
a support member having at least one inclined surface inclined relative to a reference plane;
a first magnetic detection element disposed on the at least one inclined surface and configured to detect a target magnetic field and generate a first detection signal, the first detection signal having a first amplitude that is a half of a difference between a maximum value and a minimum value of a waveform of the first detection signal if a direction of the target magnetic field changes with a predetermined period;
a second magnetic detection element disposed on the at least one inclined surface and configured to detect the target magnetic field and generate a second detection signal having a phase different from that of the first detection signal, the second detection signal having a second amplitude that is a half of a difference between a maximum value and a minimum value of a waveform of the second detection signal if the direction of the target magnetic field changes with a predetermined period; and
a conversion section configured to convert the first detection signal and the second detection signal into a first corrected signal and a second corrected signal, respectively, the conversion section being configured to change at least either one of the first amplitude of the first detection signal and the second amplitude of the second detection signal to make a ratio of a second corrected amplitude of the second corrected signal to a first corrected amplitude of the first corrected signal different from a ratio of the second amplitude of the second detection signal to the first amplitude of the first detection signal, the first corrected amplitude being a half of a difference between a maximum value and a minimum value of a waveform of the first corrected signal if the direction of the target magnetic field changes with a predetermined period, the second corrected amplitude being a half of a difference between a maximum value and a minimum value of a waveform of the second corrected signal if the direction of the target magnetic field changes with a predetermined period.
16 . The magnetic sensor according to claim 15 , wherein the maximum value and the minimum value of the first detection signal are equal to the maximum value and the minimum value of the second detection signal.