JP6572400B1 - Encoder scale, method for manufacturing the same, and control device using the same - Google Patents

Abstract

An encoder scale capable of measuring a minute position displacement with high accuracy is obtained. An encoder scale according to an embodiment is provided on a first main surface, a metal substrate having a first main surface and a second main surface provided on a surface opposite to the first main surface, and the first main surface. A plurality of recesses having a predetermined pattern, a light reflecting portion formed between a plurality of adjacent recesses, and a light absorption portion provided in the plurality of recesses, the width W1 of the light absorption portion, The height D1 has a relationship represented by D1> W1. [Selection] Figure 9

Description

  Embodiments described herein relate generally to an encoder scale, a manufacturing method thereof, and a control device using the same.

There is a mechanism called an encoder as a mechanism incorporated in a technique for accurately detecting the rotational speed and phase of a motor and a technique for accurately detecting the moving position of a movable object.
The encoder can measure the rotational position or the linear position with a sensor as a change in mechanical position, and output position information as an electrical signal.

As the encoder, a detection device and a scale are used, and there are an optical type that detects the scale with light, a magnetic type that detects with magnetism, an electromagnetic induction type that detects with electromagnetic induction, and the like, depending on the position detection method.
As an optical detection device, there is a transmission type that has a mechanism in which light is output from an optical transmitter and light that has passed through a light transmission portion (for example, a slit) of the scale plate is received by an optical receiver. Alternatively, as another optical detection device, it has an optical transceiver including a light output unit and a light reception unit, and outputs light from the light output unit toward the scale plate, and the light reflection of the scale plate There is a reflection type having a mechanism in which light reflected from the unit is received by the light receiving unit.

As a scale for measuring the position of the straight line and the rotation, for example, a linear scale, a disc scale, and a ring scale are used.
For example, a scale used in a reflective optical detection device has a light absorbing portion and a light reflector formed on a base material such as glass or PET.

  By making this scale finer, it is possible to measure a finer position displacement. Therefore, it is desired to create a fine scale with high accuracy.

JP 2017-1551074 A

  In order to solve the above problems, an object of the present invention is to obtain an encoder scale capable of measuring a minute position displacement with high accuracy.

According to the present invention, a metal substrate having a first main surface and a second main surface provided on a surface opposite to the first main surface;
A plurality of recesses having a predetermined pattern provided on the first main surface;
A light reflecting portion formed between the plurality of recesses adjacent to each other;
A light absorbing portion provided in the plurality of recesses,
An encoder scale having a relationship in which the width W1 and the height D1 of the light absorbing portion are expressed by D1> W1 is provided.

According to the present invention, a step of forming a resist layer on the base material,
Patterning by exposure and development, and forming a resist pattern layer including a plurality of convex portions having a taper from the film thickness direction toward the base material;
Plating is performed on the base material through the resist pattern layer until the resist pattern layer is buried, and a first main surface is formed on the interface with the base material, and a second main surface is formed on the surface opposite to the first main surface. Forming a plated metal layer having a surface;
Peeling the base material from the first main surface of the plated metal layer to expose a resist pattern layer on the first main surface;
Forming a metal substrate having a plurality of recesses corresponding to the plurality of protrusions on the first main surface of the plated metal layer by removing the resist pattern layer from the first main surface;
Applying a light-absorbing composition containing a light-absorbing material to the plurality of recesses, and polishing the first main surface to remove excess portions of the light-absorbing composition and to smooth the first main surface A plurality of recesses having a predetermined pattern provided on the first main surface;
Provided is an encoder scale manufacturing method including a step of forming an encoder scale including a light reflecting portion formed between the plurality of concave portions adjacent to each other and a light absorbing portion provided in the plurality of concave portions. .

Furthermore, according to the present invention, a metal substrate having a first main surface and a second main surface provided on a surface opposite to the first main surface,
A plurality of recesses having a predetermined pattern provided on the first main surface;
A light reflecting portion formed between the plurality of recesses adjacent to each other;
A light absorbing portion provided in the plurality of recesses, and a width W1 and a height D1 of the light absorbing portion, and an encoder scale having a relationship represented by D1>W1;
There is provided a control device including an optical transceiver that irradiates light to the encoder scale, receives light reflected from the encoder scale, and detects a photoelectric conversion pulse.

  According to the present invention, it is possible to obtain an encoder scale capable of measuring a minute position displacement with high accuracy.

FIG. 1 is a diagram illustrating an example of a control device according to the embodiment. FIG. 2 is a diagram illustrating another example of the control device according to the embodiment. Drawing 3 is a figure showing the manufacturing process of the scale for encoders concerning an embodiment. FIG. 4 is a diagram illustrating a manufacturing process of the encoder scale according to the embodiment. FIG. 5 is a diagram illustrating a manufacturing process of the encoder scale according to the embodiment. FIG. 6 is a diagram illustrating a manufacturing process of the encoder scale according to the embodiment. FIG. 7 is a diagram illustrating a manufacturing process of the encoder scale according to the embodiment. FIG. 8 is a diagram illustrating a manufacturing process of the encoder scale according to the embodiment. FIG. 9 is a diagram illustrating an example of the encoder scale according to the embodiment. FIG. 10 is a diagram for explaining another example of the encoder scale manufacturing method according to the embodiment.

Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows a configuration example of a motor control system using an encoder scale according to an example of a control device according to the present invention.
Reference numeral 100 denotes an encoder, which includes a scale 200A and a detection device 300. The scale 200 </ b> A is a turntable and is rotationally driven by a motor 600. The detection device 300 includes a power supply 301, an optical transceiver 302, an amplifier 303, and a pulse processing circuit 304.
The rotary disk type scale 200A is directly attached to, for example, a rotation shaft of a motor 600, and light reflection portions and light absorption portions are alternately arranged radially on the rotation surface (this structure is described later). To explain).

The optical transceiver 302 irradiates, for example, light from an LED (or laser) to the rotating surface via a half mirror (prism) and a lens, and reflects light reflected from the rotating surface via a half mirror (prism). It is received by the light receiving element. A detection signal (photoelectric conversion pulse) output from the light receiving element is amplified by the amplifier 303 and input to the pulse processing circuit 304.
The pulse processing circuit 304 performs waveform shaping of the detection signal, counting, detection of change in the count value, analog conversion of the count value, etc., and a required signal (or data; relative position data of the optical transceiver with respect to the encoder scale). Is given to the motor control device 500. The motor control device 500 processes the received signal (or data) according to a control program, and increases / decreases / stops the rotation speed of the motor 600.
In the encoder 100, the optical transceiver 302 may be configured to be movable toward the inner and outer peripheral sides of the rotary disk type scale 200A. When located on the inner peripheral side, the density of the arrangement pitch of the light reflecting part and the light absorbing part is increased, and the detection accuracy can be increased. When located on the outer peripheral side, the light reflecting part and the light absorbing part Thus, the density of the arrangement pitch is reduced, and the detection accuracy can be relaxed.

FIG. 2 shows a configuration example of a motor control system using an encoder scale according to another embodiment. Components similar to those in FIG. 1 are denoted by the same reference numerals as in FIG. The shape of the previous scale 200A was a rotating disk. And although a light reflection part and a light absorption part are radial and are arrange | positioned alternately, in embodiment of FIG. 2, the scale 200B is strip | belt shape, and a light reflection part and a light absorption part are the longitudinal direction. Are alternately arranged at equal intervals.
The scale 200B is arranged along the rail 810, for example. The rail 810 guides, for example, a box-type carriage 800, and a motor 600 is disposed in the carriage 800. The motor 600 rotates to drive the carriage 800 in the arrow XX direction. While the motor 600 is rotating and the carriage 800 is moving, the optical transceiver 300 receives the reflected light while irradiating the scale 200B with light. As a result, the detection device 300 detects the movement status (movement position) of the carriage 800. Also at this time, the position of the carriage 800 is detected with high accuracy.

As described above, the control device includes an encoder scale, an optical transceiver that irradiates light to the encoder scale and receives light reflected from the encoder scale, and detects a photoelectric conversion pulse, And a detector for obtaining relative position data of the optical transceiver with respect to the encoder scale.
Here, the encoder scale is a rotating disk and is rotated by a motor, and the detection device controls the rotation of the motor. Alternatively, the encoder scale is in the form of a straight plate and is disposed along the moving direction of the linearly moving carriage, and the detection device controls the rotation of a motor that drives the carriage.

Next, a method for manufacturing the scales 200A and 200B will be described.
3 to 9 are schematic cross-sectional views showing the manufacturing process of the scale 200B.
First, as shown in FIG. 3, a metal plate such as stainless steel having at least one surface 1 a mirror-finished is prepared as the base material 1.
Subsequently, a resist layer 2 is formed on the mirror-finished surface 1a using, for example, a resist. If necessary, the resist layer 2 can be pre-baked at a temperature of 100 to 200 ° C., for example, and the resist layer 2 can be adhered to the base material 1.
After that, on the surface 2a of the resist layer 2, the non-reflective mask 5 having a striped pattern is arranged in which the shielding portions 5b having the width r1 and the opening portions 5a having the width r2 are alternately arranged. Through the mask 5, exposure is performed from the surface 2a to the surface 2b on the opposite side of the surface 2a and in contact with the surface 1a of the metal plate 1.

At this time, by using a light source that combines light of a plurality of wavelengths as the exposure light source, the light passes through the opening 5a of the mask 5 in the film thickness direction of the resist layer 2 from the surface 2a as indicated by an arrow 101. The incident light can be controlled to spread in the vicinity of the surface 2 b opposite to the surface 2 a as indicated by an arrow 102. As light of a plurality of wavelengths, for example, light having three wavelengths of 365 nm, 385 nm, and 405 nm can be used. The light of three wavelengths can be controlled by changing the usage rate (%) and the light amount (mJ / cm ² * sec).

In addition to stainless steel, for example, a material containing Ni, Cu, Al, or the like can be used as the base material. The thickness of the base material can be set to 100 to 1000 μm, for example. If the thickness of the base material is less than 100 μm, it tends to cause warpage, and if it exceeds 1000 μm, it tends to cause warpage.
As the resist layer, a positive resist or the like having a thickness D1 that is three times the width of the opening width r1 of the non-reflective mask can be used. When the depth D1 is less than 5 μm, the reflection of the non-reflective mask tends to be bright. If it is 5 μm or more, the reflectance tends to be close to zero.

  Next, as shown in FIG. 4, after exposure, development is performed to remove the exposed resist, and there is a taper in the thickness direction toward the base material 1 in the vicinity of the surface 6 b on the base material 1 side. Then, a resist pattern 6 including a plurality of convex portions 6-1 in which the width of the surface 6b is narrower than the width of the surface 6a on the mask 5 side is formed. If necessary, the resist pattern 6 after development can be adhered to the metal plate 1 by post-baking the resist pattern 6 at a temperature of 100 to 200 ° C.

Thereafter, as shown in FIG. 5, the metal plate 1 provided with the resist pattern 6 is plated with a plating metal such as nickel, thereby filling a space between the plurality of convex portions 6-1 with the plating metal, Furthermore, plating is continued and the plating layer 7 is formed so as to cover the plurality of convex portions 6-1.
According to the method for manufacturing an encoder scale according to the embodiment, as shown in FIGS. 3 and 4, when a taper is formed by exposure and development so that an angle is formed near the surface 2 b, the surface 2 b is adjacent. Since the convex portions 6-1 separating from each other are separated and the outline becomes clear after plating, the transfer failure of the resist pattern 6 hardly occurs. Further, in the plating step, since the interval between the adjacent convex portions 6-1 is widened by the taper on the surface 2b, the subsequent plating process is easily performed.

Next, as shown in FIG. 6, the metal plate 1 is peeled off from the plating layer 7 to expose the surface 7 b that has been in contact with the metal plate 1 of the plating layer 7. For convenience of explanation, in FIG. 6, the direction of the surface 7a opposite to the surface 7b of the plating layer 7 in FIG. 5 is reversed.
Subsequently, as shown in FIG. 7, when the resist pattern 6 is peeled from the surface 7 b of the plating layer 7, a plurality of recesses 8 are provided.

As shown in FIG. 8, a mixture of, for example, carbon black and epoxy resin is applied to the surface 7b of the plating layer 7 and the plurality of recesses 8 provided on the surface 7b as a light absorbing composition containing a light absorbing material. The light-absorbing composition is applied on the recesses 8 and the surface 7b between the plurality of recesses 8 to fill the plurality of recesses 8 with the light-absorbing composition, and the light-absorbing composition embedded in the plurality of recesses 8 The light absorbing composition layer 9 is formed so as to cover the surface 7b of the plating layer 7 between the concave portions 8 with the light absorbing composition.
Thereafter, the light absorbing composition layer 9 is heated and cured at a temperature of 100 to 200 ° C., for example.
In this case, for example, carbon black or the like is used as the light absorbing material of the light absorbing portion, and a mixture dispersed in an epoxy resin is applied. However, as the light absorbing layer, a light reflecting layer for light of the same wavelength. It is possible to use a material having a reflectance different from that of the above. For this reason, the light reflecting portion is a first reflecting portion having a first reflectance with respect to predetermined light, and the light absorbing portion is a second reflecting portion having a second reflectance different from the first reflecting portion. be able to. The material used for the second reflecting portion is not limited to carbon black, and an epoxy resin, a coloring material, or the like can be used.

FIG. 9 is a diagram illustrating a final process of the encoder scale, and is a diagram illustrating an example of the encoder scale obtained by the method according to the embodiment.
As shown in FIG. 9, the light-absorbing composition layer 9 is subjected to rubbing or the like, leaving a portion 9a of the light-absorbing composition layer 9, that is, a portion 9a of the light-absorbing composition embedded in a plurality of recesses. The other portion of the composition layer 9, that is, the portion 9a and the portion 9b of the light-absorbing composition provided on the surface 7b are removed, the surface 7b is smoothed to increase the reflectance, and the light reflecting portion 7-1 is formed. obtain.
Thereby, the metal base material 7 which consists of the plating layer which has the surface 7b provided in the surface 7a and the surface 7a opposite surface, and several recessed part 8 which has the predetermined pattern provided on the surface 7a, mutually An encoder that includes a light reflecting portion 7-1 provided between the plurality of adjacent concave portions and a light absorbing portion 9a formed of a portion provided in the plurality of concave portions, and has a stripe pattern as viewed from the 7b side A scale for use 200B is obtained.

The plating layer preferably has a Vickers height (Hv) of 200 to 650 kgf / mm ² after the base material is peeled off.
In the encoder scale according to the embodiment, the width W1 of the light absorbing portion and the height D1 of the light absorbing layer can satisfy the relationship represented by D1> W1.
If D1> W1, since the light absorbing portion 9a is formed deep in the height D1 direction with respect to the surface 7b of the encoder scale 200B, the light absorbing portion 9a is difficult to peel off from the plating layer 7, and the pattern of the light absorbing layer Is less likely to be lost, and the durability of the encoder scale 200B is improved.

The ratio between the width W1 of the light absorbing portion and the height D1 is preferably in the range of 9 to 11 to 18 to 20. If it is out of this range, the pattern of the light absorption layer tends not to be lost.
In the encoder scale according to the embodiment, as shown in FIG. 9, the light absorbing portion 9 a may have a structure in which a taper is provided from the surface 7 a side to the surface 7 b side in the film thickness direction of the plating layer 7. it can. With this structure, the width W1 of the exposed surface on the surface 7b side of the light absorbing portion 9a is narrower than the width r1 of the buried surface on the surface 7a side of the light absorbing portion 9a. 9a becomes more difficult to peel off from the plating layer 7, and the pattern of the light absorption layer is less likely to be lost, so that the durability of the encoder scale 200B becomes better. Furthermore, according to the encoder scale according to the embodiment, since the pattern of the light absorption part is not easily lost in the patterning step and the shape of the light absorption part is excellent in durability, the light absorption layer and the light reflection The layer width and pitch can be designed minutely with higher accuracy.

  Further, in the encoder scale according to the embodiment, it is possible to create a convex portion without a taper. The convex part without the taper can be formed, for example, by removing the portion 9b of the light absorbing composition and further polishing and removing the tapered part in the polishing step. Even when there is no taper, the durability of the encoder scale 200B can be maintained by satisfying the relationship that the width W1 and the height D1 of the light absorbing portion are expressed by D1> W1.

  The width W1 of the exposed surface on the surface 7b side of the light absorbing portion 9a and the distance W2 between adjacent exposed surfaces are the width r1 of the opening 5a of the mask used as shown in FIG. It can be adjusted by changing the pitch r1 + r2 of the portion, the difference r3 between the width r1 and the width W1 on the surface 7b side.

In the encoder scale obtained using the steps shown in FIGS. 3 to 9, the width W1 of the exposed surface 9-1 on the surface 7b side of the light absorbing portion 9a can be set to, for example, 10 μm to 100 μm. And the distance W2 between the adjacent exposed surfaces 9-1 on the surface 7b side of the light absorbing portion 9a can be set to, for example, 10 μm to 100 μm. The ratio W1: W2 between W1 and W2 can be 1: 1.
Further, the thickness D1 of the resist pattern can be set to 10 to 50 μm, for example.
The thickness t1 of the plating layer can be set to, for example, 50 μm to 400 μm.
As shown in FIG. 9, the light absorbing portion 9a on the surface 7a side can be partially provided with a taper of 0.2 ° to 1 °. Alternatively, the taper can be provided entirely in the height D1 direction of the light absorbing portion 9a.

FIG. 10 is a view for explaining a method of manufacturing the scale 200A.
As shown in FIG. 3, in the case of the rotary disk scale 200A, instead of the mask 5 in which the shielding portions 5b and the opening portions 5a are alternately arranged in a striped pattern, the shielding portions 15b and the opening portions 15a are alternately arranged. One mask 15 provided with a plurality of mask patterns 15c of a rotating disk arranged in a radial pattern can be used.
The encoder scale 200A obtained in this manner is unlike the encoder scale 200B, and the pattern of the light absorbing portion is not easily lost in the patterning process, and the shape of the light absorbing portion is excellent in durability. The width and pitch of the absorbing layer and the light reflecting layer can be designed minutely with higher accuracy.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] A metal substrate having a first main surface and a second main surface provided on a surface opposite to the first main surface;
A plurality of recesses having a predetermined pattern provided on the first main surface;
A light reflecting portion formed between the plurality of recesses adjacent to each other;
A light absorbing portion provided in the plurality of recesses,
The width W1 and height D1 of the light absorption part are encoder scales having a relationship represented by D1> W1.
[2] The encoder scale according to [1], wherein the metal base has a strip shape, and the pattern of the plurality of recesses is a linear shape provided in the width direction.
[3] The encoder scale according to [1], wherein the metal base is a turntable, and the pattern of the plurality of recesses is radial.
[4] The encoder scale according to any one of [1] to [3], wherein the light absorbing portion has a taper toward the first main surface in a film thickness direction.
[5] The encoder scale according to any one of [1] to [4], wherein the first main surface is mirror-finished.
[6] The encoder scale according to any one of [1] to [5], wherein the ratio between the width W1 of the light absorbing portion and the height D1 is in a range of 9 to 11 to 18 to 20.
[7] A step of forming a resist layer on the base material,
Patterning by exposing and developing the resist layer, forming a resist pattern layer including a plurality of convex portions having a taper from the film thickness direction toward the base material;
Plating is performed on the base material through the resist pattern layer until the resist pattern layer is buried, and a first main surface is formed on the interface with the base material, and a second main surface is formed on the surface opposite to the first main surface. Forming a plated metal layer having a surface;
Peeling the base material from the first main surface of the plated metal layer to expose a resist layer on the first main surface;
Forming a metal substrate having a plurality of recesses corresponding to the plurality of protrusions on the first main surface of the plated metal layer by removing the resist pattern layer from the first main surface;
Applying a light-absorbing composition containing a light-absorbing material to the plurality of recesses, and
Polishing the first main surface, removing excess portions of the light-absorbing composition, and smoothing the first main surface, thereby having a plurality of patterns having a predetermined pattern provided on the first main surface A method of manufacturing an encoder scale, comprising: forming an encoder scale including a recess, a light reflecting portion formed between the plurality of recesses adjacent to each other, and a light absorbing portion provided in the plurality of recesses. .
[8] A metal substrate having a first main surface and a second main surface provided on a surface opposite to the first main surface,
A plurality of recesses having a predetermined pattern provided on the first main surface;
A light reflecting portion formed between the plurality of recesses adjacent to each other;
A light absorbing portion provided in the plurality of recesses,
The width W1 and the height D1 of the light absorption part are an encoder scale having a relationship represented by D1> W1,
A control device comprising: an optical transceiver that irradiates light to the encoder scale and receives light reflected from the encoder scale and detects a photoelectric conversion pulse.

  DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Resist layer, 5 ... Mask, 6 ... Resist pattern layer, 7b ... 1st main surface, 7a ... 2nd main surface, 7 ... Metal base material, 7-1 ... Light reflection part, 8 ... Concave part, 9-1 ... light absorption part, 100 ... control device, 200A, 200B ... scale for encoder, 300 ... detection device, 302 ... optical transceiver

Claims (8)

A metal substrate having a first main surface and a second main surface provided on a surface opposite to the first main surface;
A plurality of recesses having a predetermined pattern provided on the first main surface;
A light reflecting portion formed between the plurality of recesses adjacent to each other;
A light absorbing portion provided in the plurality of recesses,
The width W1 and height D1 of the light absorption part are encoder scales having a relationship represented by D1> W1.   2. The encoder scale according to claim 1, wherein the metal substrate has a strip shape, and the pattern of the plurality of concave portions is a linear shape provided in a width direction.   The encoder scale according to claim 1, wherein the metal base is a rotating disk, and the pattern of the plurality of recesses is radial.   4. The encoder scale according to claim 1, wherein the light absorbing portion has a taper toward the first main surface in a film thickness direction. 5. The encoder scale according to any one of claims 1 to 4, wherein the first main surface is smoothed to increase the reflectivity .   6. The encoder scale according to claim 1, wherein a ratio between the width W <b> 1 of the light absorbing portion and the height D <b> 1 is in a range of 9 to 11 to 18 to 20. Forming a resist layer on the base material;
Patterning by exposing and developing the resist layer, forming a resist pattern layer including a plurality of convex portions having a taper from the film thickness direction toward the base material;
Plating is performed on the base material through the resist pattern layer until the resist pattern layer is buried, and a first main surface is formed on the interface with the base material, and a second main surface is formed on the surface opposite to the first main surface. Forming a plated metal layer having a surface;
Peeling the base material from the first main surface of the plated metal layer to expose a resist layer on the first main surface;
Forming a metal substrate having a plurality of recesses corresponding to the plurality of protrusions on the first main surface of the plated metal layer by removing the resist pattern layer from the first main surface;
Applying a light-absorbing composition containing a light-absorbing material to the plurality of recesses, and polishing the first main surface to remove excess portions of the light-absorbing composition and to smooth the first main surface Accordingly, a plurality of recesses having a predetermined pattern provided on the first main surface, a light reflecting portion formed between the plurality of recesses adjacent to each other, and light provided in the plurality of recesses An encoder scale manufacturing method including a step of forming an encoder scale including an absorber. The encoder scale according to any one of claims 1 to 6 ,
A control device comprising: an optical transceiver that irradiates light to the encoder scale and receives light reflected from the encoder scale and detects a photoelectric conversion pulse.

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