JP2008298729A - Magnetic scale for magnetic type encoder and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic scale for a magnetic type encoder which enables setting of a high resolution and miniaturization and makes a manufacturing process simple. <P>SOLUTION: Hard and soft magnetic substances in a prescribed shape are disposed alternately one by one on a nonmagnetic substance substrate and the hard magnetic substances are magnetized perpendicularly to the surface of the substrate so as to constitute a magnetic scale. The hard and soft magnetic substances shaped like stripes are formed alternately one by one on a plane as a parallel stripe pattern so as to constitute a linear scale in the direction intersecting the stripes perpendicularly. Besides, the hard and soft magnetic substances are arranged at equal angles alternately one by one on a disk plane of a disk-shaped nonmagnetic substance, as a pattern of straight lines passing through the center of the disk, so as to constitute a disk-shaped magnetic scale. By magnetizing the portions of the hard magnetic substances in the same direction perpendicular to the surface of the nonmagnetic substance substrate, the magnetic scale having a narrow pitch and a steep magnetic field distribution is obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a magnetic scale for a magnetic encoder of a type in which a linear moving body or a rotating body with a plurality of magnetic poles magnetized is used as a magnetic scale, and its displacement is detected by a magnetic sensor, and a manufacturing method thereof.

Conventionally, the magnetic encoder has a configuration in which a magnetic medium having a magnetic pole array manufactured by magnetizing a magnetic medium formed by molding a resin containing a magnetic material is moved, and a displacement of the magnetic medium is detected by the magnetic sensor 11. Examples thereof are shown in FIG. 13 and FIG. FIG. 13A shows a magnetic scale in which magnetic poles are magnetized in parallel with the moving direction of the magnetic medium 101 formed on the non-magnetic substrate 100 that moves linearly, and a linear motion is detected by the magnetic sensor 111. . FIG. 13B shows a magnetic scale formed on the side surface of the nonmagnetic disk 103 on which the magnetic medium 101 rotates, magnetized in the tangential direction of the circumference of the nonmagnetic disk 103, and rotated by the magnetic sensor 111. It is to detect. (For example, refer to Patent Documents 1 and 2).

In general, such a magnetic encoder is magnetized in the in-plane direction of a magnetic medium to form a magnetic scale, and when the magnetic scale moves, the strength of the magnetic field is converted into an electric signal by a magnetic sensor for position detection. Do. What detects a linear motion is a linear encoder shown in FIG. 13A, and what detects a rotational motion is a rotary encoder shown in FIG. 13B. In the linear encoder of FIG. 13A, the magnetic scale 110 linearly moves to change the magnetic field intensity that passes perpendicularly through the magnetic field detection surface of the magnetic sensor 111, thereby detecting the number of times the magnetic field intensity fluctuates. The amount of movement of the moving body on which the magnetic substrate 100 is mounted is detected.

  A conventional magnetic scale 110 for a linear encoder will be described with reference to FIG. In the conventional magnetic scale 110 made of a so-called plastic magnet that contains magnetic powder in the resin as a magnetic medium, it is attached so that the N and S poles alternate on the surface of the plastic magnet used as the scale. Magnetize. That is, magnetization is performed so that magnetic domains in the magnetic pole direction, which are S poles and N poles, are formed adjacent to magnetic domains in the magnetic pole direction of N poles and S poles, and the directions of the magnetic poles are alternately reversed. With respect to the magnetization pitch, for example, a pitch repeated from a north pole to an adjacent north pole as a set is defined as one pitch. At present, the minimum pitch of the magnetic scale made of plastic magnets is approximately 100 μm. Since a magnetic sensor needs to detect a change in magnetic field with a pitch of about 100 μm, a magnetoresistive effect sensor that mainly changes the electric resistance due to magnetism and extracts the change in the electric resistance as an electric signal is mainly used. In the magnetic encoder, the obtained signal is divided to obtain a position signal equal to or smaller than the magnetization pitch.

  For high-precision encoders, both linear motion detection and rotation detection methods have been widely used in the past, but in recent years, processing oil and printing have been used in office equipment such as machining equipment and printers. There is a need for an encoder for precise position control that operates in an environment where liquid-like liquid such as industrial ink is scattered. In such an environment, the optical encoder may cause a position detection error due to adhesion of oil or dust, and a magnetic type is required instead of the optical type.

Further, in office equipment such as a printing press, there is a great demand for downsizing the outer shape of the equipment, and it is required to reduce the volume for installing the encoder. As for optical encoders, rotary encoders having an outer diameter of 10 mm or less have already been commercialized, but magnetic encoders are also required to be small-sized encoders as in the optical type.
Japanese Patent Laid-Open No. 10-300514 JP-A-10-170211

However, the magnetization pitch in the conventional magnetic encoder is larger than 100 μm due to the limitation of the magnetization method as compared with the pitch of the optical encoder. In the conventional method of manufacturing the magnetic scale 110 that is magnetized on the surface of the magnetic medium 101 shown in FIG. 14, the magnetizing head 120 is placed close to the plastic magnet 101 that is a magnetic medium and moved relatively to determine the position. And magnetize. When the magnetic yoke 121 is brought close to the plastic magnet 101 and a magnetic signal is written on the surface of the plastic magnet 101 to make the magnetic scale 110 for the linear encoder, the N pole and the S pole are alternately reversed on the surface of the plastic magnet 101. Magnetization is performed so that For this reason, when the magnetization pitch is small, a phenomenon occurs in which the adjacent signals are written in a superimposed manner, resulting in a problem that the recorded magnetic intensity is remarkably lowered and the resolution is deteriorated. For this reason, the magnetization pitch of the magnetic encoder is generally larger than the pitch of the scale of the optical encoder. If the same pitch as that of the optical encoder can be realized in the magnetic encoder, the resolution can be increased as in the optical encoder. To this end, however, the resolution of the magnetic scale itself is changed by changing the magnetization method. Need to be expensive.

In order to reduce the volume required for installation in equipment that requires precise position control, miniaturization of the magnetic encoder is required, and a magnetic scale with a small magnetization pitch has been developed for miniaturization of the encoder. It is necessary to In order to realize a rotary encoder with an outer diameter of 10 mm or less as in the optical type and to obtain an output of 256 pulses or 512 pulses per rotation, it is necessary to manufacture a magnetic scale with a pitch of 10 μm to 500 μm. It is.

In a magnetic scale manufactured by magnetizing a conventional magnetic medium, the distance between the magnetic scale and the magnetic sensor needs to be as small as several tens of micrometers in order to obtain the sensitivity of the magnetic sensor. It is necessary to make the gap between the magnetic scale and the sensor as small as possible so as to avoid contact, and keep this gap constant. It is necessary for practical use that this distance can be increased, and therefore, the magnetic field intensity generated from the magnetic scale needs to be large.

  In the magnetic scale magnetization process of the conventional manufacturing process, the surface of the plastic magnet 101 is magnetized as shown in FIG. For this reason, it is necessary to feed the plastic magnet 101 at a constant pitch and magnetize it with the magnetic yoke 121 of the magnetic head 120. For this reason, a high-accuracy feeding mechanism is required for the magnetizing device, and the time required for the magnetizing process is the accumulated time of writing time for each magnetic domain, N pole-S pole or S pole-N pole. is necessary. If a structure that can be magnetized at one time can be manufactured in advance, rather than a method of magnetizing with a magnetic head, it is possible to improve the magnetization accuracy and reduce the time required for the magnetizing process.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic scale for a magnetic encoder that is small in size, can sufficiently improve resolution, and has a simple manufacturing process.

  In order to solve the above-described problems, the present invention includes a magnetic scale that functions as a magnetic signal train recorded on a magnetic medium, and a magnetic sensor disposed opposite to the magnetic medium. In a magnetic scale for a magnetic encoder having a configuration in which a medium is arranged so as to move in the vicinity of a magnetic sensing portion of a magnetic sensor, a plurality of fixed-shaped hard magnetic materials and a plurality of fixed-shaped media are formed on a non-magnetic substrate. It is characterized in that a soft signal recording body is formed by alternately arranging soft magnetic bodies.

  The applicants of the present application, unlike the magnetic field of a magnet magnetized by alternately reversing the magnetic poles formed on a conventional plastic magnet, has N magnetized on the scale surface while the magnetized magnetic pole is only in one direction. A new idea of a magnetic scale has been invented in which a magnetic field in which poles and S poles are arranged alternately is formed. The present invention utilizes a phenomenon in which a reverse magnetic field is formed in a soft magnetic material adjacent to a magnetized hard magnetic material in a structure in which hard magnetic materials and soft magnetic materials are alternately arranged. A magnetic encoder is configured by detecting a change in the magnetic field by placing the sensor surface of the magnetic sensor facing the plane of the hard magnetic material and the surface of the soft magnetic material.

In the present invention, the hard magnetic bodies are magnetized in the same direction perpendicular to the surface of the magnetic scale and arranged in a plurality, and in the plurality of soft magnetic bodies installed between the hard magnetic bodies, A magnetic field in which the positions of the N pole and the S pole are reversed with respect to the adjacent hard magnetic material is generated. As a result, an arrangement of magnetic body rows in which the positions of the N pole and the S pole are alternately reversed is formed. Therefore, the magnetic encoder can be configured by arranging the sensor surface of the magnetic sensor so as to face the surface of the magnetic body row with respect to the arrangement of the magnetic bodies.

Further, in the present invention, the sensor surface of the magnetic sensor can be disposed horizontally close to the magnetic pole surface of the hard magnetic material and the soft magnetic material, and the detection accuracy is improved by placing the sensor surface in a portion where the magnetic field strength is large. It is possible to improve.

In the present invention, each of the hard magnetic body and the soft magnetic body is characterized by a linear shape having a width in the range of 10 μm to 500 μm.

In the present invention, it is preferable that the adjacent hard magnetic body and the soft magnetic body are not in contact with each other and have a magnetic gap.

In the present invention, the hard magnetic body is composed of, for example, an Fe—Co based magnetic body, and the soft magnetic body is composed of, for example, an Fe—Ni based magnetic body.

In the present invention, the linear shape of the hard magnetic material or the linear shape of the soft magnetic material is a linear shape configured as a set of parallel linear patterns or dot patterns obtained by further finely dividing the inside of the magnetic material. May be.

The method of manufacturing a magnetic scale for a magnetic encoder according to the present invention includes a step of forming a hard magnetic body and a soft magnetic body on a nonmagnetic substrate by plating, and a step of magnetizing the hard magnetic body.

In the present invention, a photoresist is applied to a plate-like nonmagnetic material, developed, and the portions other than the portion to be plated are covered with the photoresist. For the plating solution, a plating solution containing cobalt sulfate and ferrous sulfate as a component is used for Fe-Co, and electroplating is performed using a commercially available plating solution for Fe-Ni. It is preferable to adjust the composition ratio of the plating solution according to the required magnetic properties. When plating of the first magnetic material is completed, the plate is washed with water to remove the plating solution, and then the photoresist is removed. A photoresist layer is provided again to cover the portion other than the portion to be plated, and the second magnetic material is plated to form a structure in which the magnetic materials are arranged. After that, a hole shape for fixing as a magnetic scale or a hole shape for inserting and fixing the shaft is formed, and the outer shape is cut off. After the heat treatment is performed on the separated magnetic scale material, the magnetic scale for the magnetic encoder is obtained by magnetizing the plated hard magnetic material in the thickness direction.

In the present invention, since the pattern of the hard magnetic material and the soft magnetic material is plated on the opening of the resist produced by photolithography, the dimension of the opening width of the mask pattern produced by photolithography is the magnetic scale of the magnetic material. The width of the linear shape. The linear shape pattern of the hard magnetic material and the soft magnetic material is formed by photolithography, and each magnetic material is plated. Therefore, the pitch size of the magnetic scale is reflected as it is as the pitch of the opening of the mask. It does not reflect misalignment between masks that occurs during mask exposure. Therefore, it is possible to easily manufacture a magnetic scale with less variation in pitch as compared with a manufacturing method in which magnetization is performed while performing pitch feed. The accuracy of the pitch dimension variation of the photolithographic mask pattern can be suppressed to 1 μm or less, and a magnetic scale having a pitch accuracy of 1 μm or less can be manufactured.

In the present invention, in order to form the pattern of the hard magnetic material and the soft magnetic material, each magnetic material is plated after forming the pattern by photolithography. Will be equal. Therefore, it is possible to easily manufacture a magnetic scale having a small size as compared with a manufacturing method in which magnetization is performed by performing conventional pitch feed. Since the minimum width of the opening that can be created by the photolithographic pattern is several μm, a magnetic pattern with a width of several μm is possible, and a magnetic scale with a minimum pitch of 10 μm can be easily manufactured.

Due to the above effects, for example, in a rotary encoder having an outer diameter of 10 mm, when a 256 pitch pattern is produced on the circumference of a nonmagnetic substrate disk having a diameter of 8 mm, the pitch is approximately 100 μm, and the magnetic property of this pitch is It is fully possible to produce a magnetic scale with a body pattern. According to the present invention, an ultra-small magnetic scale for a magnetic encoder can be manufactured.

In the present invention, the linear shape of the hard magnetic material or the linear shape of the soft magnetic material is not a single, uniform shape, but can be formed as a complex shape. For example, a linear shape configured as a set of parallel linear patterns or dot patterns obtained by further finely dividing the inside of the magnetic material can be used. By utilizing the shape of this pattern, it is possible to obtain magnetic characteristics different from those of a single uniform linear shape. For example, a soft magnetic linear pattern formed of parallel linear patterns has an advantage that the apparent relative permeability can be increased as compared with a uniform soft magnetic linear pattern.

The manufacturing method according to the present invention is characterized in that the magnetic scale can be formed in the process of magnetizing only the hard magnetic material in one direction, compared to the conventional process of writing the magnetic signal by changing the magnetization direction one by one. Since the linear shape of the hard magnetic material can be set to the magnetizing step only by magnetizing it once in the direction perpendicular to the surface, a magnetic scale with high positional accuracy can be manufactured by a simple process.

The best mode for carrying out the present invention will be described with reference to the drawings.

1A and 1B are a perspective view and a cross-sectional view, respectively, schematically showing the configuration of a magnetic scale for a linear encoder to which the present invention is applied. 2A and 2B are an explanatory diagram showing the positional relationship between the magnetic scale and the magnetic sensor in the magnetic encoder according to Embodiment 1 of the present invention, and an equivalent circuit of the magnetic sensor.

As shown in FIGS. 1A and 1B, the magnetic scale 10 according to the present embodiment is a magnet having an arrangement of a magnetic material pattern composed of a linear hard magnetic body 2 and a linear soft magnetic body 3. A linear hard magnetic body 2 which is a scale and is formed on the nonmagnetic substrate 1 is magnetized in a direction perpendicular to the plane of the nonmagnetic substrate 1. In FIG. 3, the surface on the nonmagnetic substrate 1 side is the S pole, and the surface on the opposite side of the nonmagnetic substrate 1 is magnetized so as to be the N pole.

Magnetic simulation by the finite element method was performed on the magnetic scale 10 of this embodiment. FIG. 5 is a diagram for explaining the conditions of the magnetic simulation. The cross-sectional shape is a linear shape having a width of 200 μm and a height of 300 μm with a space of 100 μm between the hard magnetic materials having a width of 200 μm and a height of 300 μm. The magnetic field strength on the surface of the magnetic material when the soft magnetic material was placed was calculated. FIG. 6 shows a simulation result, in which the magnetic field strength in the direction perpendicular to the surface at the position of the magnetic material surface is graphed. In FIG. 6, when the hard magnetic material is magnetized at 400 mT and a magnetic field is generated, the upper surface of the soft magnetic material placed between the hard magnetic materials is the place where the absolute value of the magnetic flux density is the largest. -77mT magnetic field is generated. That is, a magnetic field in which the magnetic poles are reversed is generated on the soft magnetic material placed between the hard magnetic material patterns, and this magnetic flux density distribution can be used as a magnetic scale magnetic field signal. In the magnetic linear encoder of this embodiment, as shown in FIG. 3, the magnetic field is vertically upward on the hard magnetic body 2, and the magnetic field is downward on the soft magnetic body 3. A rotating magnetic field whose direction changes is formed.

The soft magnetic material used for the simulation was an Fe—Ni alloy (Fe 22%, Ni 78%) having a high magnetic permeability, and magnetic characteristic data having a hysteresis curve with an initial permeability of 30000 was used. The hard magnetic material is assumed to be a surface magnetic flux of 400 mT assuming a samarium cobalt magnet.

As shown in FIG. 2 (a), the magnetic scale 10 of this embodiment, which is composed of an array of magnetic material patterns, is installed facing the magnetic sensor 11, and the magnetic sensor 11 and the magnetic scale 10 are in the lateral direction of the figure. The relative position is detected by relative movement. For example, in an apparatus on which an encoder such as a machine tool is mounted, if one of the magnetic sensor 11 or the magnetic scale 10 is fixed and the other is arranged in the moving part of the apparatus, the moving speed or movement of the moving part relative to the fixed part The distance can be detected.

In the magnetic sensor 11, a magnetoresistive element 12 and a magnetoresistive element 13 are formed on a substrate 18, and a circuit element such as an amplifier, a lead wire for connecting the magnetoresistive element 12 and the magnetoresistive element 13 to the circuit element, etc. The electrical wiring is built in, and the surface of the magnetoresistive element 12 functions as a sensor surface. The substrate 18 is a glass substrate or a ceramic glaze substrate, and the magnetoresistive element 12 and the magnetoresistive element 13 formed on the surface of the substrate 18 have a resistance pattern made of a magnetic film such as a ferromagnetic Ni—Fe. Become. As the substrate 18, a silicon substrate, a ferrite substrate, or the like is also used according to the specifications of the encoder. As shown in FIG. 2, the resistance values of the magnetoresistive element 12 and the magnetoresistive element 13, which are the magnetic sensing parts of the magnetic sensor, are set to be substantially equal, and the midpoint potential is output from the electrode 16. In the magnetic sensor 11, the back side of the surface on which the magnetoresistive element 12 and the magnetoresistive element 13 are formed on the substrate 18 may be a sensor surface.

  The operation when the magnetic sensor 11 and the magnetic scale 10 are combined will be described with reference to FIG. The hard magnetic body 2 and the soft magnetic body 3 on the magnetic scale 10 form a linear pattern in which N poles and S poles are alternately arranged along the moving direction of the magnetic scale 10. When the interval between the magnetic bodies 2, that is, between the N pole and the N pole is 1 pitch, the corresponding position of the magnetic sensor is shifted by a quarter pitch in the moving direction.

  As shown in FIG. 3, when the magnetoresistive element 12 is located immediately above the hard magnetic body 2 and the magnetoresistive element 13 is located at a position shifted from immediately above the soft magnetic body 3, the resistance of the magnetoresistive element 12 is reduced. The resistance of the magnetoresistive element 13 does not change while no magnetic field is applied, and is relatively larger than the resistance value of the magnetoresistive element 12. An equivalent circuit of the magnetoresistive element 12 and the magnetoresistive element 13 is shown in FIG. 2B, and the potential of the electrode 16 of the magnetoresistive element 12 and the magnetoresistive element 13 is the power supply voltage in the state of FIG. Greater than half.

When the magnetic sensor 11 is moved from directly above the hard magnetic body 2 in the state shown in FIG. 3 and the magnetoresistive element 12 is moved between the hard magnetic body 2 and the soft magnetic body 3, the resistance of the magnetoresistive element 12 is Returning to the resistance in a state where no magnetic field is applied, the magnetoresistive element 13 is directly above the hard magnetic body 2 and the resistance of the magnetoresistive element 13 is reduced. Therefore, the potential at the connection point 16 decreases as the magnetic scale moves. By measuring the voltage based on the magnetic pattern and the position of the magnetic sensor, the amount of movement between the magnetic sensor 11 and the magnetic scale 10 can be converted into an electrical signal.

Therefore, in the magnetic encoder using the magnetic scale 10 of this embodiment, an electrical signal is output from the magnetic sensor 11 according to the pitch at which the hard magnetic body 2 and the soft magnetic body 3 are formed and the moving speed of the magnetic sensor, The relative movement speed and the relative movement distance between the magnetic scale 10 and the magnetic sensor 11 can be detected from the electric signal.

A copper plate having a length of 30 mm, a width of 14 mm, and a thickness of 0.5 mm was used as a nonmagnetic substrate, and a hard magnetic pattern and a soft magnetic pattern having a length of 10 mm and a width of 30 μm were alternately formed on the upper surface by plating at a pitch of 60 μm. The pitch between the same kind of magnetic materials is 120 μm. The hard magnetic material was plated with an Fe—Co alloy, and the soft magnetic material was plated with an Fe—Ni alloy so as to have a stripe shape having a substantially square section with an aspect ratio of 1. The composition ratio of the Fe—Co alloy was 45% Fe and 55% Co. The Fe—Ni alloy had a composition ratio of Fe 20% and Ni 80%. A magnetic field having a magnetic flux density of 0.75 T was uniformly applied to magnetize the Fe—Co alloy.

4A and 4B are a perspective view and a cross-sectional view, respectively, schematically showing a configuration of a magnetic scale for a linear encoder to which the present invention is applied. The positional relationship between the magnetic scale and the magnetic sensor in the magnetic encoder according to the second embodiment of the present invention is the same as that in the first embodiment, and will be described with reference to FIGS.

As shown in FIGS. 4A and 4B, the magnetic scale 10 of the present embodiment is a magnetic scale composed of an array of magnetic material patterns composed of a hard magnetic material pattern 21 and a soft magnetic material pattern 31. It is formed on the non-magnetic substrate 1. The hard magnetic material pattern 21 is magnetized in a direction perpendicular to the plane of the non-magnetic substrate 1. In FIG. 4B, the S pole is magnetized on the surface on the nonmagnetic substrate 1 side, and the N pole is magnetized on the surface facing the nonmagnetic substrate 1.

The internal structure of the soft magnetic pattern 31 will be described with reference to FIGS. The structure in which the hard magnetic material patterns 21 and the soft magnetic material patterns 31 are alternately arranged along the moving direction is formed on the nonmagnetic substrate 1 as in the first embodiment. The pattern 31 is divided and formed from a fine stripe pattern.

As shown in FIG. 2, the magnetic scale 10 of this embodiment in which the magnetic material patterns are arranged is installed to face the magnetic sensor 11, and the magnetic sensor 11 and the magnetic scale 10 are relatively moved in the longitudinal direction. To detect the relative position.

7 and 9, the conditions of the magnetic simulation by the finite element method in the magnetic scale 10 of this embodiment will be described. 7 and 9, the outer shape and arrangement of the hard magnetic body and the soft magnetic body, and the magnetization strength of the hard magnetic body are the same as those in FIG. 7 shows the case where the linear shape of the soft magnetic material is divided into three thin plates, and FIG. 9 shows the case where the linear shape of the soft magnetic material is divided into six plates. FIG. 8 is a graph showing the magnetic field strength on the surface of the magnetic material in FIG. 7, and FIG. 10 is a graph showing the magnetic field strength on the surface of the magnetic material in FIG. On the upper surface of the soft magnetic material in FIG. 6, a magnetic field of −77 mT is generated at a place where the absolute value of the magnetic flux density in the vertical direction is the largest, whereas in FIGS. 8 and 10, it is −83 mT or −110 mT. It is a value. That is, the magnetic field on the soft magnetic body 31 placed between the hard magnetic bodies 21 is divided into finer stripe patterns in the soft magnetic body 31, thereby increasing the apparent permeability, and the soft magnetic body linear shape. The magnetic field strength on the shape can be increased.

When the hard magnetic material 21 is magnetized and has a magnetic field directed upward in the drawing, a magnetic field directed downward in the drawing is generated in the soft magnetic material 31, and the direction in the direction perpendicular to the plane of the magnetic scale 10 changes. A magnetic field is formed. As a result of the magnetic field analysis of Example 1, it can be seen that the magnetic field in the downward direction of the drawing passing through the soft magnetic body 31 is large in FIG.

Therefore, in the magnetic encoder using the magnetic scale 10 of this embodiment, the output that can be detected by the magnetic sensor 11 can be increased, and a position signal with a low noise level can be obtained.

In any of the above embodiments, the magnetic encoder is configured as a linear encoder, but a rotary encoder can be configured with a magnetic scale according to the present invention. 11A and 11B are a perspective view and a cross-sectional view, respectively, schematically showing the configuration of a magnetic scale for a rotary encoder to which the present invention is applied. FIG. 12 is an explanatory diagram showing a planar positional relationship between the magnetic scale 10 and the magnetic sensor 11 in the magnetic rotary encoder according to the third embodiment of the present invention.

As shown in FIGS. 11 (a) and 11 (b), the magnetic scale of this embodiment is a magnetic scale composed of an array of magnetic patterns composed of a hard magnetic body 2 and a soft magnetic body 3, and is a non-magnetic body. It is formed on the substrate 1. The hard magnetic body 2 is magnetized in a direction perpendicular to the plane of the nonmagnetic substrate 1. In FIG. 11, the S pole is magnetized on the surface on the nonmagnetic substrate 1 side, and the N pole is magnetized on the opposite surface of the nonmagnetic substrate 1.

As shown in FIG. 12, a magnetic scale 10 of this embodiment, which is an array of magnetic material patterns formed on a disk-like nonmagnetic substrate 1, is placed opposite to a magnetic sensor 11. Is rotated and the magnetic pattern is moved in the rotation direction to detect the relative position. For example, in a mounting apparatus such as a machine tool, if the center of the magnetic scale 10 is fixed to the rotation shaft and the magnetic scale is arranged so as to rotate, the rotation angle and the rotation speed are determined by the electrical output of the magnetic sensor 11 arranged oppositely. Can be detected.

The operation when the magnetic scale 10 and the magnetic sensor 11 are combined is the same as that of the first embodiment, and the description thereof is omitted.

Also in the magnetic scale for the rotary encoder, it is possible to divide a rectangular linear pattern of soft magnetic material similar to that of the second embodiment and to form a fine stripe pattern. It is the same and description is omitted.

As a conventional small and high-precision magnetic scale, a magnet obtained by magnetizing a plastic magnet is used. The magnetic encoder based on the magnetic scale of the present invention can be made smaller and more accurate.

In addition, it is possible to increase the stability of the scale with respect to temperature compared to the one using a plastic magnet, and by selecting a non-magnetic substrate material with a low expansion coefficient, a scale that does not require temperature correction can be used. It can be configured. The displacement of the magnetic scale due to temperature occurs due to the thermal expansion of the nonmagnetic substrate. Magnetic scales made of conventional plastic magnets are used with temperature compensation due to their large thermal expansion, but by using ceramic or quartz glass as a non-magnetic substrate, no magnetic compensation is required. It can be a scale.

In addition, since it is more resistant to radiation damage than plastics, a magnetic scale that can be used for position control that requires accuracy in an environment where radiation is used can be obtained. Therefore, it is possible to manufacture a medical device that uses radiation and a magnetic encoder for precisely performing position control in outer space. In these applications, the optical encoder uses a light receiving element made of a semiconductor inside, and cannot be used because of the large noise caused by radiation. This is an industrial field in which a highly accurate magnetic encoder is required.

The present method for producing the magnetic medium of the magnetic encoder by plating can reduce the thickness and weight of the magnetic medium and can also reduce the pitch. As a rotary encoder, the size and weight can be reduced, and the resolution can be increased. ADVANTAGE OF THE INVENTION According to this invention, the magnetic encoder which can be used in the environment where the conventional optical encoder was not used is realizable.

(A), (b) is the perspective view and sectional drawing which respectively show the structure of the magnetic scale for linear encoders to which this invention is applied. Example 1 (A), (b) is explanatory drawing which shows the positional relationship of the magnetic scale and magnetic sensor which concern on this invention, respectively, and the equivalent circuit of a magnetic sensor. Example 1 In the magnetic encoder which concerns on this invention, it is explanatory drawing which shows the positional relationship of a magnetic scale and a magnetic sensor. (Example 2) (A), (b) is the perspective view and sectional drawing which respectively show the structure of the magnetic scale for linear encoders to which this invention based on this invention is applied. (Example 2) It is explanatory drawing of the simulation of the magnetic field intensity in the magnetic scale of this invention. Example 1 It is a simulation result of the magnetic field strength in the Example of this invention. Example 1 It is explanatory drawing of the simulation conditions of the magnetic field intensity in the magnetic scale of this invention. (Example 2) It is a simulation result of the magnetic field strength in the Example of this invention. (Example 2) It is explanatory drawing of the simulation conditions of the magnetic field intensity in the magnetic scale of this invention. (Example 2) It is a simulation result of the magnetic field strength in the Example of this invention. (Example 2) (A), (b) is the perspective view and sectional drawing which respectively show the structure of the magnetic scale for magnetic rotary encoders which concerns on this invention. (Example 3) It is explanatory drawing which shows the positional relationship of the magnetic scale and magnetic sensor in the magnetic rotary encoder which concerns on this invention. (Example 3) (A), (b) is explanatory drawing of the conventional magnetic encoder, respectively. It is explanatory drawing of the manufacturing method of the conventional magnetic encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Nonmagnetic board | substrate 2,21 Hard magnetic body 3,31 Soft magnetic body 10,110 Magnetic scale 11,111 Magnetic sensor 12,13 Magnetoresistive element 15,16,17 Electrode 18 Substrate 101 Magnetic recording medium 103 Nonmagnetic body Disk 120 Magnetic head 121 Magnetic yoke

Claims (5)

  A magnetic scale acting as a magnetic signal train recorded on the magnetic medium and a magnetic sensor disposed opposite to the magnetic medium are arranged so that the magnetic medium moves in the vicinity of the magnetic sensing part of the magnetic sensor. A magnetic scale for a magnetic encoder having the above-described configuration, wherein a plurality of fixed-shaped hard magnetic bodies and a plurality of fixed-shaped soft magnetic bodies are alternately arranged on a non-magnetic substrate every other piece. A magnetic scale for a magnetic encoder, characterized in that a magnetic signal train is recorded.   2. The magnetic scale for a magnetic encoder according to claim 1, wherein each of the hard magnetic body and the soft magnetic body has a linear shape with a width of 10 [mu] m to 500 [mu] m.   2. The magnetic scale for a magnetic encoder according to claim 1, wherein the magnetic encoder is composed of an Fe—Co magnetic material as a hard magnetic material and an Fe—Ni magnetic material as a soft magnetic material. Magnetic scale.   3. A magnetic scale for a magnetic encoder according to claim 1 or 2, wherein the linear shape of the hard magnetic material or the linear shape of the soft magnetic material further divides the interior of the magnetic material into finer lines. A magnetic scale for a magnetic encoder, characterized in that the magnetic scale is a linear shape configured as a group of dot patterns or dot patterns. 4. The method for manufacturing a magnetic scale for a magnetic encoder according to claim 1, further comprising a step of forming a magnetic body on a nonmagnetic substrate by plating and a step of magnetizing the hard magnetic body. The manufacturing method of the magnetic scale for magnetic encoders of Claim 1 to 3.