JP2002228485A - Magnetic encoder and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic encoder capable of being used irrespective of the diameter of a drum by improving a resolution and to provide a magnetic encoder capable of dealing with a magnetic drum of a different magnetizing pitch desirably by one type of a magnetic sensor. SOLUTION: The magnetic encoder comprises a magnetic medium having a magnetic element for recording a magnetic signal changing at a period A along a moving direction of the medium at an oblique angle to the moving direction, and the magnetic sensor having a plurality of MR elements linearly disposed. The magnetic sensor is opposed to the medium so that dispositions of the MR elements become substantially perpendicular direction to the moving direction to obtain an output signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for magnetically detecting a position, and more particularly, to an encoder for detecting a rotation angle or a rotation speed of a rotary machine or a rotary electric machine, or a linear encoder. .

[0002]

FIG. 8 is a side view of a conventional magnetic encoder. The configuration of the magnetic encoder will be described.
The magnetic drum 10 is attached to the rotating shaft 102 of the motor 101.
5, the outer periphery of the magnetic drum 105 is made of a magnetic material on which a magnetic signal is recorded. A magnetic sensor 104 having a magnetoresistive element is fixed to the motor 101 by a mounting jig 103 so as to face the outer periphery of the magnetic drum 105. Hereinafter, the magnetoresistive effect element is referred to as M
It is called an R element.

[0005] FIG. 9 is a schematic diagram showing an unfolded surface of the magnetic drum 105 and the magnetic sensor 104 shown in FIG. A magnetic signal is recorded at the recording wavelength λ on the surface of the magnetic material of the magnetic drum. With respect to this λ (corresponding to the phase 2π), the MR elements R11 to R1
4, R21 to R24 are arranged on the magnetic sensor 104. The interval between adjacent MR elements is λ / 4. These MR elements are connected as in the equivalent circuit of FIG. 10 to form two sets of bridge circuits, and an output e1 between the terminals a1 and a2 and an output e2 between the terminals b1 and b2 are obtained. e
Waveforms 1 and e2 are shown in FIG. As shown in FIG. 11 (a), the terminals a1, b1, a2 and b2 are passed through amplifier circuits OPa and OPb, and further subjected to waveform shaping to form a rectangular wave, and as shown in FIG. Phase outputs A and B are obtained. That is, the rotation of the magnetic drum 105 provides two-phase outputs with a λ / 4 phase shift. At this time, the period of the waveform is the recording wavelength λ of the magnetic drum surface.
, Which is the resolution of the magnetic encoder. The number of pulses per rotation corresponds to the number of magnetized pulses. here,
It is practical that the recording wavelength λ is several tens to several hundreds μm.

[0004]

The following methods (1) and (2) have been studied to change the resolution of the magnetic encoder using the magnetic sensor described above. (1) Changing the outer diameter of the magnetic drum. (2) Changing the recording wavelength. That is, there are a method of increasing the number of signal pulses by fixing the recording wavelength λ and increasing the outer diameter of the magnetic drum, and a method of changing the recording wavelength λ with the same outer diameter. However, in the method (1), it is only necessary to change the outer diameter of the magnetic drum, and it is not necessary to change the arrangement of the MR elements. However, it is difficult to cover all resolutions due to restrictions on the size of the magnetic drum. It is not suitable as a method for improving the resolution. In the method (2), the arrangement of the MR element patterns must be changed in accordance with the change of the recording wavelength λ.
As the number of types of R element patterns increases, facilities such as photomasks used for manufacturing the patterns also increase. Also, a plurality of M
When the R element pattern is further expanded and arranged in the horizontal direction, FIG.
The problem described in 2 arises. The horizontal direction corresponds to a direction parallel to the arrow Z in FIGS.

FIG. 12 is a sectional view for explaining the relationship between the magnetic sensor and the magnetic drum. The arrangement pattern of the MR elements is a complicated pattern in order to meet conditions such as the detection accuracy of the diameter of the magnetic drum, the rotation angle and speed, and suppression of noise. Usually, in the magnetic sensor 104, MR
The element is manufactured on a substrate such as glass or Si. Since a flat plate-shaped substrate is used, if the curvature (magnitude) on the surface (curved surface) of the corresponding magnetic drum 105 is large, the MR element pattern spreads in the horizontal direction (parallel to the arrow Z). Central part 104a and end part 104b
Then, the distance (gap) from the magnetic drum changes. That is, g1 <g2. If the magnetic fields applied to the central portion 104a and the end portion 104b are different, MR having the same sensitivity
Even if an element is used, the output magnitude differs between the central portion 104a and the end portion 104b, so that it becomes difficult to detect the rotation angle and the rotation speed of the magnetic drum with high accuracy (position detection accuracy decreases). Therefore, an object of the present invention is to obtain a magnetic encoder that can improve the resolution and can be used regardless of the drum diameter. More desirably, it is an object of the present invention to obtain a magnetic encoder that can suppress types of MR element patterns and can cope with magnetic media having different recording wavelengths.

[0006]

According to the present invention, there is provided a magnetic encoder comprising: a magnetic medium on which a magnetic signal that changes at a period λ along a moving direction of a magnetic medium is recorded; and a bridge circuit facing the magnetic medium. A magnetic sensor is provided in which a plurality of constituent MR elements are linearly arranged in a direction intersecting the movement direction, and the phases of magnetic signals corresponding to the respective MR elements are different. More preferably, the plurality of MR elements are linearly arranged in a direction orthogonal to the moving direction. Here, in order to make the phases of the magnetic signals corresponding to the respective MR elements different from each other in the magnetic medium, the phases of the magnetic signals of the tracks corresponding to the respective MR elements may be sequentially shifted.

[0007] Another magnetic encoder of the present invention converts a magnetic signal that changes at a period λ along the moving direction of a magnetic medium,
A magnetic medium having a magnetic material recorded at an inclination angle with respect to the movement direction, and a magnetic sensor in which a plurality of MR elements are linearly arranged, and the arrangement of the MR elements is substantially perpendicular to the movement direction. An output signal is obtained by causing a magnetic sensor to face the magnetic medium so as to be in the direction.

In another magnetic encoder of the present invention, a pitch between adjacent MR elements among the plurality of MR elements is L, and an inclination angle θ with respect to a moving direction of the magnetic signal is θ = tan ⁻¹ ( L / P) and P = mλ / 4, where (m = 1, 2, 3,...). Further, the magnetic encoder according to the present invention using the track formed by inclining the magnetic signal and magnetizing the magnetic material can reduce the harmonic component of the output signal of the magnetic sensor. The reason for harmonic reduction will be described. The output characteristic of the MR element is a waveform including a third harmonic in a sine wave. In order to accurately detect the rotation angle of the magnetic drum (position detection), it is desirable to remove the third harmonic and obtain a sine wave. When the magnetic signal of the track is inclined as in the configuration of the present invention, a large number of magnetic fields shifted in phase are applied to one MR element, and the outputs shifted in phase are integrated in one MR element. The same effect as described above can be obtained, and the third harmonic component of the output can be removed.

[0009] Still another magnetic encoder according to the present invention comprises:
A magnetic medium having a magnetic material that records a magnetic signal with at least two or more tracks provided with a magnetic signal that changes at a period λ along the moving direction of the magnetic medium, with a phase difference between the tracks, A magnetic sensor in which corresponding MR elements are linearly arranged, and an output signal is obtained by facing the magnetic sensor to the magnetic medium so that the arrangement of the MR elements is substantially perpendicular to the moving direction. Features. The rows of the plurality of MR elements are linearly arranged so as to be substantially perpendicular to the moving direction of the track.

In still another magnetic encoder according to the present invention, the phase difference between the tracks is m / 4 times the period λ of the magnetic signal (where m = 1, 2, 3,...). It is characterized by the following. In order to enhance the position detection accuracy of the output signal of the magnetic sensor, a configuration in which the output signal of the MR element is output in two phases or a configuration in which the MR element is connected as disclosed in Japanese Patent Publication No. 5-26124 is applied. Can be considered. Of these, a magnetic encoder having a phase difference between tracks of mλ / 4 is often used, but a magnetic gap shift occurs depending on the curvature of the magnetic drum. Therefore, if a magnetic sensor in which the MR element of the present invention is linearly arranged is applied to the configuration having the phase difference mλ / 4, it is possible to prevent a position detection error due to a gap shift. this is,
The size of the gap between the MR element and the track is different for each MR.
This is because the elements are the same.

[0011] Still another magnetic encoder according to the present invention comprises:
A magnetic material recorded on at least two or more tracks with a magnetic signal that changes at a period λ along the moving direction of the magnetic medium, and a phase difference between the tracks and an inclination angle with respect to the moving direction. And a magnetic sensor in which MR elements corresponding to each track are linearly arranged, and a magnetic sensor is provided on the magnetic medium such that the arrangement of the MR elements is substantially perpendicular to the moving direction. An output signal is obtained by facing each other.

In another magnetic encoder according to the present invention, the phase difference between the tracks is m / 4 times (where m = 1, 2, 3,...) The period λ of the magnetic signal. , The pitch of a plurality of MR elements corresponding to each track is L
The inclination angle θ of the magnetic signal with respect to the moving direction is as follows: θ = tan ⁻¹ (L / P), and P = nλ / 4, where (n = 1, 2, 3,...) It is characterized by the relationship.

Each of the above-described embodiments of the present invention includes a magnetic sensor in which a plurality of MR element patterns are linearly arranged in a direction substantially perpendicular to the moving direction of a magnetic medium, and a magnetic signal phase and a magnetic signal arrangement and pattern. Since the gap of each MR element becomes the same by using the shifted magnetic medium,
The position can be accurately detected regardless of the drum diameter. In particular, when the diameter of the magnetic drum is reduced, the resolution can be improved by applying the configuration of the present invention.
In the above magnetic sensor, a plurality of MR elements are arranged in a line on a substrate. The magnetic sensor and the magnetic medium are opposed or slid so that the direction of the row is substantially orthogonal to the moving direction of the magnetic medium. The plurality of MR elements constitute a bridge circuit.

Here, "arranged linearly" means that a plurality of MR elements are arranged on a straight line in a direction substantially perpendicular to the moving direction of the magnetic medium. Even if it is necessary to change the magnitude of the fixed period λ constituting the magnetic signal, it is possible to cope with different magnetic signal pitches only by changing the magnetic pattern of the magnetic medium. In addition, even for magnetic media having different curvatures, it is possible to keep substantially the same distance between the magnetic medium and the MR element. The magnitude of the magnetic field applied from the magnetic medium to the MR element is the same, and the position can be detected with high accuracy without being affected by the curvature of the magnetic drum. That is, the present invention can be applied to a magnetic drum having a small diameter to a magnetic drum having a large diameter, and further to a linear encoder having a flat magnetic medium.

The terms will be further explained. The magnetic medium includes a movable magnetic medium, a planar magnetic medium used for a linear encoder, a rotating body or a magnetic drum provided with the magnetic medium. The moving direction of the magnetic medium corresponds to the direction in which the magnetic medium is moved or the rotating direction of the magnetic drum or the like. The substantially vertical direction includes a state in which the magnetic sensor is tilted by 90 degrees or a state in which the output signal of the magnetic sensor is slightly shifted from 90 degrees but is equivalent to a configuration in which the output signal of the magnetic sensor is tilted by 90 degrees. In the present invention, the magnetic sensor is an MR sensor.
Sensor using element, GM using GMR element
An R sensor or the like can be used. The pitch L between adjacent MR elements is the pitch L between adjacent MR elements and a center point of a certain MR element.
This is the distance between the center points of the R elements and corresponds to the pitch when the MR elements are arranged (different from the pitch λ of the magnetic signal).
The inclination angle θ includes both a direction in which the magnetic signal is inclined by + θ and a direction in which the magnetic signal is inclined by −θ with respect to the moving direction of the magnetic medium, and can be set to any direction. A track is a magnetized area of a magnetic material,
It corresponds to the area surface on which the MR element detects on the magnetic medium.

A method for manufacturing a magnetic encoder according to the present invention is a method for manufacturing the magnetic encoder according to any one of the above-described embodiments, wherein a magnetic signal is recorded on each track by a magnetizing head. Provided with a magnetizing head,
It is characterized in that the magnetization of each magnetization head is performed in parallel with the phase difference of the track being shifted. When this manufacturing method is used, the magnetization can be performed in a shorter time than a method in which a plurality of tracks are sequentially magnetized by one magnetization head.
A magnetic core in which an exciting coil is wound around a yoke is used as a magnetizing head. A current is supplied from a power source to the coil, a magnetic field is applied to the magnetic medium from the gap of the magnetic core while moving the magnetic medium, and a magnetic signal having a pitch λ is recorded on the track. A control device for controlling the moving speed of the magnetic medium and the magnitude and interval of the current flowing for each magnetizing head is provided, and the magnetizing processes of the tracks are executed in parallel with a phase difference.
In order to perform magnetization by shifting the phase difference, the first method of shifting the timing of the current flowing for each magnetizing head to provide a phase difference is performed.
And a second manufacturing method in which the relative arrangement between the magnetization heads is shifted to provide a phase difference. More specifically, in the first manufacturing method, the plurality of magnetizing heads are arranged in a direction substantially perpendicular to the moving direction of the magnetic medium during recording, and the magnetizing operations of the adjacent magnetizing heads are adjacent to each other. This can be performed in parallel by shifting the phase difference of the tracks.
In the second manufacturing method, the plurality of magnetizing heads can be arranged obliquely to the moving direction of the magnetic medium during recording, and the magnetizing heads can simultaneously perform the magnetizing operation.

Another method of manufacturing a magnetic encoder according to the present invention is a method of manufacturing the magnetic encoder according to any one of the above-described present invention, wherein the magnetic signal is recorded on the track by a magnetizing head. The magnetic gap of the magnetizing head is characterized by being arranged to be inclined with respect to the moving direction of the magnetic medium. More specifically, as a configuration in which the magnetic core is inclined, a first configuration in which the magnetic core of the conventional magnetizing head is inclined with respect to the moving direction, or a magnetic gap is provided in advance with the magnetic core inclined with respect to the magnetic core itself. The second configuration or the like can be used. To form the track width with higher precision, it is desirable to use the second configuration.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is an embodiment of the present invention and schematically illustrates a magnetic drum and a magnetic sensor which are magnetized by tilting a magnetic signal. FIG. 1A is a schematic diagram in which the pattern of the MR element of the magnetic sensor 4a and the magnetization pattern of the magnetic drum 5a are developed on a plane. The magnetic sensor 4a includes four MR elements R11, R21, R12, and R2.
2 were arranged side by side on a straight line (in a direction parallel to the arrow X in the figure), and the distance between the center points of adjacent MR elements was L. In the magnetic drum 5a, one track was formed by magnetizing the magnetic body at a recording pitch λ at an angle θ with respect to the rotation direction of the magnetic drum (the direction of the arrow Z in the figure).
The following relationship holds between L and θ. θ = tan ⁻¹ (L / P) and P = λ / 4. With this configuration, the magnetic field applied to the MR element causes a λ / 4 phase difference between adjacent MR elements. By forming the bridge circuit by connecting the MR elements so as to obtain the equivalent circuit diagram of FIG. 1B, the output signals ea and eb shown in the output waveform diagram of FIG. 1C can be obtained. Was. This configuration, due to the linear arrangement of the MR elements and the inclined magnetized tracks, has a
The position detection accuracy was improved by about 10%.

(Embodiment 2) FIG. 2 is a schematic diagram for explaining another embodiment of the present invention. FIG. 2A is a schematic diagram in which the pattern of the MR element of the magnetic sensor 4b and the magnetization pattern of the track of the magnetic drum 5b are developed on a plane.
The configuration of the entire magnetic encoder is the same as that shown in FIG. As shown in FIG. 2A, the magnetic sensor 4b is provided with the patterns of the four MR elements R11, R21, R12, and R22 in the moving direction of the magnetic medium (the direction parallel to the arrow Z in the figure). They were arranged vertically and linearly.
On the other hand, four tracks on the magnetic drum 5b were arranged so as to correspond to each MR element, and the phase difference between adjacent tracks was λ / 4. The other tracks 2 to 4 were recorded with magnetic signals shifted from the track 1 so that the phase difference was mλ / 4 (where m = 1, 2, 3). The pitch of the magnetic signal indicated by NS was λ.

The pattern of the four MR elements is shown in FIG.
Connected to a bridge circuit as shown in the equivalent circuit diagram shown in FIG.
Outputs ea and eb were obtained from the connection point between R11 and R12 and the connection point between R21 and R22. Since the magnetic fields applied to the respective MR elements are out of phase, an output as shown in the output waveform diagram of FIG. 1C could be obtained. Since the MR elements were linearly arranged along the direction parallel to the arrow X, the rotational position of the magnetic drum could be detected with high accuracy regardless of the diameter of the magnetic drum. In this configuration, due to the linear arrangement of the MR elements, the position detection accuracy could be improved by about 7% as compared with the configuration of the related art.

(Embodiment 3) FIG. 3 shows another embodiment of the present invention, and is a schematic diagram in which the pattern of the MR element of the magnetic sensor 4c and the magnetization pattern of the magnetic drum 5c are developed on a plane. This pattern corresponds to a pattern in which two sets of the configuration in FIG. 2 are arranged. The magnetic sensor 4c has R1
1, R21, R12, R22, R14, R24, R1
Patterns of eight MR elements 3, R23 are linearly arranged perpendicular to the moving direction of the magnetic medium (the direction parallel to the arrow Z). On the other hand, eight tracks on the magnetic drum 5c are arranged so as to correspond to each MR element. Tracks 1 to 4 are arranged on the magnetic drum 5c in the same phase relationship as in FIG. 2 so as to correspond to the MR elements R11, R21, R12, R22.
3 and R23 so as to correspond to similar tracks 1-4.
Was provided on the magnetic drum 5c. The phase difference between adjacent tracks was λ / 4. Each track has a phase difference of mλ / 4 (where m = 1, 2, 2) with respect to the top track 1.
3, 4, 5, 6, 7).

FIG. 4 is an equivalent circuit diagram of the configuration of FIG.
It corresponds to a full bridge circuit. The output signal of the magnetic sensor can be doubled as compared with the configuration of FIG. 2, and the power line noise can be canceled.
Since the equivalent circuit itself is the same as that of FIG. 9, the detailed description is omitted. In the configuration of FIG. 9, the accuracy of position detection is deteriorated by the diameter of the magnetic drum, whereas the configuration of FIG. 3 can be used regardless of the diameter of the magnetic drum, and the position detection of the magnetic drum is performed in the same manner as the configuration of FIG. I was able to.

(Embodiment 4) FIG. 5 is a schematic view showing another embodiment of the present invention, in which the pattern of the MR element of the magnetic sensor 4d and the magnetization pattern of the magnetic drum 5d are developed on a plane. This pattern corresponds to a configuration in which the two tracks in the configuration in FIG. 3 are replaced with one track in which a magnetic signal is inclined and magnetized. The magnetic sensor 4d includes R1
1, R21, R12, R22, R14, R24, R1
Patterns of eight MR elements 3, R23 are arranged linearly perpendicular to the rotation direction of the magnetic drum (the direction parallel to the arrow Z). On the other hand, four tracks 1 to 4 were formed on the magnetic drum 5d by magnetizing the magnetic body at a pitch λ at an angle θ with respect to the rotation direction of the magnetic drum. The following relationship holds between L and θ. θ = tan ⁻¹ (L / P) and P = λ / 4. One track corresponds to two MR elements. The phase difference between adjacent tracks was λ / 4. The equivalent circuit of the MR element was the same as in the third embodiment. By detecting the tilted magnetic signal of each track with a pair of MR elements, the harmonic component of the output signal of the magnetic sensor could be reduced.

FIG. 6 is a schematic diagram for explaining an embodiment according to the manufacturing method of the present invention. (A) in FIG. 6 is (a) in FIG.
4 shows how four tracks are formed using four magnetizing heads on the magnetic drum 5b. Magnetizing heads 6a, 6b,
6c and 6d are arranged in parallel along the axial direction of the magnetic drum (the direction parallel to the arrow X), their magnetic gaps are brought close to the magnetic material on the surface of the magnetic drum, and the magnetic drum is moved to the arrow z.
Magnetization was performed while rotating in the direction of a. By using the control device 7a that supplies a current to each of the four magnetized heads with a phase shifted, magnetizing could be performed by providing a phase difference of λ / 4 between adjacent tracks. FIG. 6 (b)
As shown in the figure, the magnetizing heads are arranged with a phase difference of λ / 4 shifted in the direction of arrow Z, and in-phase currents are simultaneously applied to the respective magnetizing heads, and the magnetizing head is rotated while rotating in the direction of arrow za. The same effect was obtained by using the method of (1).

FIG. 7A is a schematic perspective view of one of the magnetizing heads used in FIGS. 6A and 6B. In these manufacturing methods, a magnetizing head was formed by winding an energizing coil around a soft magnetic yoke, and terminals of the coil were connected to a control device and a power supply 7a. FIG. 7B shows the magnetized head 6a.
3 shows the positional relationship between the magnetic gap 8 and the track moving direction za. Magnetization was performed so that the width direction of the magnetic gap 8 was substantially perpendicular to the track length direction. FIG. 7C is a schematic diagram showing the positional relationship between the magnetic gap 18 in the magnetizing head 16 and the track moving direction za when magnetizing by inclining the magnetic signal. By previously providing the magnetic gap 18 in the magnetizing head 16 at an angle, the magnetic signal could be tilted in the track moving direction za to magnetize the track.

According to the configuration of the above-described embodiment, only one type of magnetic sensor is required, and it is possible to cope with various resolutions by shifting the recording pitch λ and the phase of the track. Here, one type refers to a pattern in which MR elements are arranged in a straight line. The change of the recording pitch λ of the track could be dealt with by changing the circuit processing or the like when magnetizing the magnetic material of the magnetic drum. It was possible to change the recording pitch without changing equipment such as manufacturing a photomask required when increasing the types of magnetic sensors. In addition, since the arrangement pattern of the MR elements is linear and the distance between all the MR elements and the magnetic drum can be the same, the magnitude of the magnetic field applied between the MR elements is also the same, and high position detection accuracy can be obtained. Was completed.

[0027]

As described above, the magnetic medium in which the phase of the magnetic signal is shifted by the arrangement and pattern of the magnetic signal,
By using the magnetic encoder of the present invention having a magnetic sensor in which MR elements are linearly arranged, by suppressing the spread of the MR element in the moving direction, the resolution can be improved and the magnetic element can be used regardless of the diameter of the magnetic medium. it can. further,
By arranging the MR elements in a straight line, it is possible to suppress the types of MR element patterns and to cope with magnetic drums having different recording wavelengths.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a magnetic encoder according to the present invention.

FIG. 2 is a schematic diagram illustrating another magnetic encoder of the present invention.

FIG. 3 is a schematic diagram illustrating another magnetic encoder of the present invention.

FIG. 4 is an equivalent circuit diagram of the configuration of FIG. 3;

FIG. 5 is a schematic diagram illustrating still another magnetic encoder according to the present invention.

FIG. 6 is a schematic diagram illustrating a manufacturing method according to the present invention.

FIG. 7 is a schematic diagram illustrating a magnetized head according to the present invention.

FIG. 8 is a side view of a conventional magnetic encoder.

FIG. 9 is a schematic diagram in which the opposing surfaces of a conventional magnetic drum and a magnetic sensor are developed.

FIG. 10 is an equivalent circuit diagram when the MR element of FIG. 9 is connected.

11 is a schematic diagram illustrating an output of the equivalent circuit of FIG.

FIG. 12 is a cross-sectional view illustrating a gap between an MR element and a magnetic drum in a conventional magnetic encoder.

[Explanation of symbols]

4a magnetic sensor, 5a magnetic drum, 4b magnetic sensor, 5b magnetic drum, 4c magnetic sensor, 5c
Magnetic drum, 4d magnetic sensor, 5d magnetic drum, 6a 6b 6c 6d magnetizing head, 7 coil, 7a manufacturing apparatus and power supply, 8 magnetic gap, 1
6 magnetizing head, 18 magnetic gap, 101 motor, 102 rotating shaft, 103 mounting jig, 1
04 Magnetic sensor, 104a Central part of MR element pattern, 104b End of MR element pattern, 105 Magnetic drum

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[Procedure amendment]

[Submission date] August 27, 2001 (2001.8.2
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 11

Claims (9)

[Claims] 1. A magnetic medium in which a magnetic signal that changes at a period of λ along a moving direction of a magnetic medium is recorded, and a plurality of MR elements forming a bridge circuit facing the magnetic medium are arranged in the moving direction. A magnetic encoder comprising: magnetic sensors arranged linearly in a direction intersecting each other, wherein phases of magnetic signals corresponding to the respective MR elements are different. 2. A magnetic medium having a magnetic material in which a magnetic signal that changes with a period λ along a moving direction of a magnetic medium is recorded at an inclination angle with respect to the moving direction, and a plurality of MR elements are linearly formed. A magnetic sensor disposed on the magnetic medium so as to obtain an output signal by facing the magnetic sensor to the magnetic medium so that the arrangement of the MR element is substantially perpendicular to the moving direction. . 3. An adjacent M among the plurality of MR elements.
When the pitch of the R element is L, the inclination angle θ with respect to the moving direction of the magnetic signal is θ = tan ⁻¹ (L / P) and P = mλ / 4, where (m = 1, 2, 3,. The magnetic encoder according to claim 2, wherein the relationship is as follows. 4. A magnetic signal which changes at a period λ along a moving direction of a magnetic medium is provided on at least two or more tracks,
A magnetic medium having a magnetic material on which the magnetic signal is recorded with a phase difference between the tracks, and a magnetic sensor in which MR elements corresponding to each track are linearly arranged; A magnetic sensor facing the magnetic medium to obtain an output signal so as to be substantially perpendicular to the magnetic medium. 5. The phase difference between tracks is m / 4 times the period λ of a magnetic signal (where m = 1, 2, 3,...).
The magnetic encoder according to claim 4, wherein 6. A magnetic signal that changes at a period λ along a moving direction of a magnetic medium is provided on at least two or more tracks,
While providing a phase difference between the tracks, a magnetic medium having a magnetic material recorded with an inclination angle with respect to the moving direction, and a magnetic sensor in which MR elements corresponding to each track are linearly arranged, A magnetic encoder, wherein an output signal is obtained by causing a magnetic sensor to face the magnetic medium so that the arrangement of the MR element is substantially perpendicular to the moving direction. 7. The phase difference between the tracks is m / 4 times the period λ of the magnetic signal (where m = 1, 2, 3,...).
For a plurality of MR elements corresponding to each track, the pitch between adjacent MR elements is L, and the inclination angle θ with respect to the moving direction of the magnetic signal is θ = tan ⁻¹ (L / P), and P = Nλ / 4, where (n = 1,2,3, ...). The magnetic encoder according to claim 6, wherein: 8. The method for manufacturing a magnetic encoder according to claim 4, wherein a magnetic head is provided for each track when a magnetic signal is recorded on the track by the magnetic head. A method of manufacturing a magnetic encoder, wherein the magnetization of each of the magnetization heads is performed in parallel with the phase difference of the tracks shifted. 9. The method of manufacturing a magnetic encoder according to claim 2, wherein the magnetic head records a magnetic signal on the track by using the magnetic head. A method for manufacturing a magnetic encoder, wherein the magnetic gap is arranged to be inclined with respect to the moving direction of the magnetic medium.