Reflective optical scale for encoder, reflective optical encoder, method for manufacturing reflective optical scale for encoder, and polygonal reflective optical scale body for encoder

Abstract

To provide a reflective-type optical scale for an encoder that reduces an outer peripheral sag area.SOLUTION: A reflective-type optical scale for an encoder has a disk-shaped metal substrate having a first surface and a second surface facing the first surface, and a low-reflection layer disposed on the first surface side of the metal substrate in a patterned shape along a circumferential direction of the metal substrate. The metal substrate has a reflectance of 50% or more on at least the first surface side, and a thickness of 0.05 mm or more and 0.60 mm or less. The metal substrate has a sag on an outer peripheral edge on the first surface side, and the sag has a width of 500 μm or less. The metal substrate has a perforated disk shape including a center hole, and the difference between the inner diameter and the outer diameter of the perforated disk-shaped metal substrate is 8 mm or more and 13 mm or less. The ratio of the thickness T2 at an outer peripheral end of the metal substrate to the thickness T1 of the metal substrate (T2 / T1) is 0.70 or more and 0.90 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a reflective optical scale for an encoder, a reflective optical encoder, a method for manufacturing a reflective optical scale for an encoder, and a polygonal reflective optical scale body for an encoder. [Background technology]

[0002] Optical encoders have traditionally been used in servo motors and other devices equipped with control mechanisms. Optical encoders are classified into transmissive and reflective types, but reflective encoders have a shorter optical path than transmissive encoders, making them easier to make smaller and thinner, and also have the advantage of being easier to assemble because there is no need to position the light-emitting element or light-receiving element.

[0003] A reflective optical encoder includes a reflective optical scale, a light source such as an LED that irradiates the scale with light, and a photodetector that detects light reflected from the scale. The reflective optical scale has reflective areas (highly reflective areas) and non-reflective areas (lowly reflective areas) arranged alternately, and the reflectance of light in the reflective areas is higher than the reflectance of light in the non-reflective areas (for example, Patent Document 1). As a result, the intensity of light reflected from the scale and incident on the photodetector varies depending on the position of the scale. The photodetector detects the intensity of light that changes as the position of the scale moves in the length measurement direction. The reflective optical encoder processes displacement information about the position of this scale according to the detected intensity of light, and can obtain position information. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-241248 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, reflective optical scales are manufactured by singulating a polygonal assembly in which a plurality of reflective optical scales are arranged side by side. In the singulation process, etching is often used for singulation because it has good processing accuracy. However, singulation by etching is disadvantageous in terms of cost.

[0006] Therefore, the inventors of the present application attempted to separate a polyhedral assembly of a reflective optical scale by punching. However, scales separated by punching suffer from sagging on the outer periphery (hereinafter also referred to as "peripheral sagging"). The inventors of the present application found that peripheral sagging in a low-reflection region where a low-reflection layer is formed can cause peeling or cracks in the low-reflection layer. Therefore, they considered not pre-positioning a low-reflection layer in the region where peripheral sagging occurs due to punching. However, optical scales for encoders typically require a low-reflection region of a predetermined size depending on the encoder device. Therefore, providing a region without a low-reflection layer at the outer periphery of the optical scale increases the actual scale size. Therefore, there is a need for a reflective optical scale for encoders in which the peripheral sagging region caused by punching is reduced.

[0007] The present invention has been made in view of the above circumstances, and has as its main object to provide a reflective optical scale for an encoder in which the outer peripheral sagging region is reduced. [Means for solving the problem]

[0008] One embodiment of the present disclosure provides a reflective optical scale for an encoder, comprising: a disk-shaped metal substrate having a first surface and a second surface opposite to the first surface; and a low-reflection layer arranged in a pattern along the circumferential direction of the metal substrate on the first surface side of the metal substrate, wherein the metal substrate has a reflectivity of 50% or more on at least the first surface side, the thickness of the metal substrate is 0.05 mm or more and 0.60 mm or less, the metal substrate has a sagging on the outer peripheral edge on the first surface side, and the width of the sagging is 500 μm or less.

[0009] Another embodiment of the present disclosure provides a reflective optical encoder comprising: the above-mentioned reflective optical scale for an encoder; a light source that irradiates measurement light onto the surface of the reflective optical scale for an encoder on which the low-reflection layer is disposed; and a photodetector that detects reflected light from the reflective optical scale for an encoder.

[0010] Another embodiment of the present disclosure provides a method for manufacturing a reflective optical scale for an encoder, the method comprising: a step of producing a multi-sided body having a metal substrate to be processed, the metal substrate having a first surface and a second surface opposite the first surface, the reflectivity of at least the first surface side being 50% or more, the metal substrate having a thickness of 0.05 mm or more and 0.60 mm or less, and patterned low-reflection layers arranged in a circular pattern and multi-sidedly attached to the first surface side of the metal substrate to be processed, the multi-sided body having planned peripheral punching lines for the reflective optical scale for an encoder formed outside the outer peripheral surfaces of each of the low-reflection layers; and a singulation step of punching out the multi-sided body along the planned peripheral punching lines to singulate the multi-sided body, thereby obtaining the reflective optical scale for an encoder.

[0011] Another embodiment of the present disclosure provides a polygonal reflective optical scale body for an encoder, comprising: a metal substrate to be processed having a first surface and a second surface opposite the first surface, wherein the reflectivity of at least the first surface is 50% or more, and the thickness of the metal substrate is 0.05 mm or more and 0.60 mm or less; and patterned low-reflection layers arranged in a circular pattern and attached to the first surface side of the metal substrate to be processed in multiple faces, wherein planned peripheral punching lines for the reflective optical scale for an encoder are formed outside the outer peripheral surfaces of each of the low-reflection layers, and the distance between the planned peripheral punching lines for the reflective optical scale for an encoder and the outer peripheral surface of the low-reflection layer is 500 μm or more and 1500 μm or less. [Effects of the Invention]

[0012] The present disclosure has an effect of providing a reflective optical scale for an encoder in which the peripheral sagging region is reduced. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic top view illustrating a reflective optical scale for an encoder according to the present disclosure. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view illustrating a reflective optical scale for an encoder according to the present disclosure. [Figure 3] 1 is a schematic cross-sectional view illustrating a reflective optical scale for an encoder according to the present disclosure. [Figure 4] 1 is a schematic perspective view illustrating a reflective optical encoder according to the present disclosure. [Figure 5] 1 is a schematic top view illustrating a reflective optical scale polygon for an encoder according to the present disclosure. FIG. [Figure 6] 1 is a schematic cross-sectional view illustrating a punching device used in a singulation step in a manufacturing method for a reflective optical scale for an encoder according to the present disclosure. FIG. [Figure 7] 10 is a graph showing the results of Experimental Examples 1-1 to 1-6 and Experimental Examples 2-1 to 2-5. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure includes embodiments of a reflective optical scale for an encoder, a reflective optical encoder, a manufacturing method for a reflective optical scale for an encoder, and a polygonal reflective optical scale body for an encoder. Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure can be embodied in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, for clarity of explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings will be designated by the same reference numerals, and detailed description may be omitted as appropriate.

[0015] In this specification, when describing an aspect in which another component is placed on a certain component, the term "above" or "below" refers to both a case in which another component is placed directly above or below the component so as to be in contact with the component, and a case in which another component is placed above or below the component with another component interposed therebetween, unless otherwise specified. Also, in this specification, when describing an aspect in which another component is placed on the surface of a certain component, the term "on the surface side" or "on the surface" refers to both a case in which another component is placed directly above or below the component so as to be in contact with the component, and a case in which another component is placed above or below the component with another component interposed therebetween, unless otherwise specified.

[0016] In addition, in this specification, the "reflective optical scale for an encoder" may be simply referred to as the "optical scale."

[0017] The reflective optical scale for an encoder, the reflective optical encoder, the method for manufacturing a reflective optical scale for an encoder, and the polygonal reflective optical scale body for an encoder according to the present disclosure will be described in detail below.

[0018] A. Reflective optical scale for encoders Fig. 1 is a schematic top view showing an example of a reflective optical scale for an encoder according to the present disclosure. Fig. 2(a) is an enlarged cross-sectional view taken along line AA of a portion a enclosed by a dotted line in Fig. 1. Fig. 2(b) is an enlarged cross-sectional view taken along line BB of a portion b enclosed by a dotted line in Fig. 1.

[0019] The reflective optical scale 10 for an encoder shown in FIGS. 1 and 2 includes a disk-shaped metal substrate 1 having a first surface 1a and a second surface 1b opposite the first surface 1a, and a low-reflection layer 2 arranged in a pattern along the circumferential direction of the metal substrate 1 on the first surface 1a side of the metal substrate 1. In the present disclosure, the reflectivity of at least the first surface 1a of the metal substrate 1 is equal to or greater than a predetermined value, and the thickness of the metal substrate 1 itself is within a predetermined range. Furthermore, as shown in FIG. 2(b), the metal substrate 1 has a sag P on the outer periphery on the first surface 1a side, and the width X of the sag P is equal to or less than a predetermined value. The reflective optical scale 10 for an encoder shown in FIG. 1 has a perforated disk shape, and low-reflection regions R2, which are regions where the low-reflection layer 2 is provided, and high-reflection regions R1, which are regions where the low-reflection layer 2 is not provided, are arranged alternately in the circumferential direction. The low-reflection region R2 includes the metal substrate 1 and the low-reflection layer 2 in the thickness direction of the reflective optical scale 10 for an encoder. The high-reflection region R1 has a metal base material 1. The reflectance of light in the high-reflection region R1 is higher than the reflectance of light in the low-reflection region R2. The reflectance of light in the high-reflection region R1 and the reflectance of light in the low-reflection region R2 indicate reflectances at the same wavelength and at the same incident angle.

[0020] The reflective optical scale for an encoder according to the present disclosure has a sagging on the outer peripheral edge of the first surface side of the metal substrate, and the width of the sagging is equal to or less than a predetermined value. Such an optical scale having a sagging on the outer peripheral edge of the metal substrate is typically manufactured by punching. Therefore, it is more cost-effective than an optical scale manufactured by etching. Furthermore, an optical scale with a reduced outer peripheral sagging region of the metal substrate can narrow the width of the region where the low-reflection layer is not formed, thereby suppressing peeling and cracking of the low-reflection layer while suppressing enlargement of the scale size. The reflective optical scale for an encoder according to the present disclosure will be described in detail below.

[0021] 1.Metal base material (1) Peripheral sagging The metal substrate according to the present disclosure is disk-shaped, has a first surface and a second surface opposite the first surface, and has a sagging portion on the outer periphery of the first surface. Furthermore, the width of the sagging portion of the metal substrate according to the present disclosure is 500 μm or less, preferably 450 μm or less, more preferably 400 μm or less, and particularly preferably 350 μm or less. If the width of the sagging portion is too large, it may overlap with the region where the low-reflection layer is formed, which may cause peeling or cracking of the low-reflection layer. On the other hand, the width of the sagging portion of the metal substrate according to the present disclosure is, for example, 10 μm or more, and may be 100 μm or more, 200 μm or more, or 250 μm or more. If the width of the sagging portion is too small, waviness may occur in the scale. Specifically, the width of the sagging of the metal substrate in the present disclosure is, for example, 10 μm or more and 500 μm or less, preferably 100 μm or more and 450 μm or less, more preferably 200 μm or more and 400 μm or less, and particularly preferably 250 μm or more and 350 μm or less.

[0022] In this specification, the width of the sagging refers to the distance X between the point where the first surface 1a of the metal base 1 starts to sag and the extension of the outer circumferential surface 1c of the metal base 1, as shown in FIG. 2(b). The measurement method for the width of the sagging, i.e., distance X, is as follows. First, the metal substrate is cut perpendicular to the first surface using methods such as metal snips, shearing, or laser cutting, and the cut surface is polished flat using a grinder to obtain a measurement sample. The cut surface of the measurement sample is observed under a microscope perpendicular to the cut surface, and the distance X between the point where the first surface 1a of the metal substrate 1 begins to sag and an extension of the outer peripheral surface 1c of the metal substrate 1 is measured. The point where the first surface 1a of the metal substrate 1 begins to sag is the point where it is no longer parallel to the flat portion of the first surface of the metal substrate 1, specifically, a point at least 3 μm away in the vertical direction. The width of the outer peripheral sagging is the average value observed and measured at a total of 12 points, in 30° increments around the circumference of the scale.

[0023] The amount of sagging of the metal substrate in the present disclosure is, for example, 500 μm or less, preferably 450 μm or less, more preferably 400 μm or less, and particularly preferably 350 μm or less. If the amount of sagging is too large, there is a risk of breakage due to insufficient strength of the scale. On the other hand, the amount of sagging of the metal substrate in the present disclosure is, for example, 10 μm or more, preferably 200 μm or more, more preferably 250 μm or more, and particularly preferably 300 μm or more. If the amount of sagging is too small, there is a risk of waviness occurring in the scale. Specifically, the amount of sagging of the metal substrate in the present disclosure is, for example, 10 μm or more and 500 μm or less, preferably 200 μm or more and 450 μm or less, more preferably 250 μm or more and 400 μm or less, and particularly preferably 300 μm or more and 350 μm or less.

[0024] In this specification, the amount of sagging refers to the distance Y between the upper end of the outer peripheral surface 1c of the metal base material 1 (the boundary point between the sagging and the outer peripheral surface 1c) and an extension line of the first surface 1a of the metal base material, as shown in Figure 2(b). The amount of sagging, i.e., the distance Y, is measured by preparing a measurement sample in the same manner as the above-described method for measuring the width of the sagging, and measuring the distance Y. The upper end of the outer peripheral surface 1c of the metal base 1 (the boundary point between the sagging and the outer peripheral surface 1c) is defined as a point that is no longer parallel to the outer peripheral surface 1c of the metal base 1, specifically, a point that is 3 μm or more away in the planar direction.

[0025] Furthermore, the ratio (T2 / T1) of the thickness T2 at the outer peripheral edge of the metal base to the thickness T1 of the metal base (described later) is, for example, 0.70 or more, and may be 0.80 or more. If T2 / T1 is too small, there is a risk of breakage due to insufficient strength of the scale. On the other hand, the ratio may be, for example, 0.90 or less, and may be 0.87 or less. If T2 / T1 is too large, there is a risk of waviness occurring in the scale. Specifically, in the present disclosure, the ratio (T2 / T1) of the thickness T2 at the outer peripheral edge of the metal substrate to the thickness T1 of the metal substrate is preferably 0.70 or more and 0.90 or less, and more preferably 0.80 or more and 0.87 or less.

[0026] When the metal substrate according to the present disclosure is a perforated disk, it may have a sagging portion on the inner peripheral edge of the first surface side (hereinafter also referred to as an inner peripheral sagging portion). The width and amount of the inner peripheral sagging portion may be the same as or different from the width and amount of the outer peripheral sagging portion.

[0027] (2)Reflectance The metal substrate according to the present disclosure has a reflectance of at least the first surface of 50% or more, preferably 55% or more, or even 60% or more, and the reflectance is, for example, 100% or less. Specifically, the reflectance of the first surface of the metal substrate in the present disclosure is, for example, 50% or more and 100% or less, preferably 55% or more and 100% or less, and more preferably 60% or more and 100% or less.

[0028] The reflectance referred to here refers to the reflectance of detection light used in, for example, an optical encoder. When the incident light has a wavelength within the range of 500 nm to 1000 nm, and the incident angle is within the range of 5° to 70°, the reflectance is preferably within the above range. The reflectance can be measured using a SolidSpec 3700DUV manufactured by Shimadzu Corporation, with an irradiation beam size of approximately 6 mm x 15 mm. Measurements are taken for both P-polarized and S-polarized light, and the sum is averaged to calculate the 45° linear polarization and the reflectance is calculated. If the reflectance of the metal substrate is within the above range, the difference between the reflectance in the high-reflection region and the reflectance in the low-reflection region is large, preventing false detection by the photodetector and improving signal detection accuracy.

[0029] (3) Thickness The metal substrate in the present disclosure has a thickness T1 of 0.05 mm or more, preferably 0.1 mm or more, and more preferably 0.3 mm or more. If the thickness of the metal substrate is within the above range, the strength as a reflective optical scale for an encoder is sufficient. On the other hand, the thickness T1 of the metal substrate is 0.60 mm or less, preferably 0.50 mm or less, and more preferably 0.4 mm or less. If the thickness of the metal substrate is within the above range, it is easy to set the width of the peripheral sag within the above range. Note that the thickness T1 of the metal substrate refers to the average thickness of the metal substrate excluding the sag region. Specifically, the thickness T1 of the metal base material in the present disclosure is 0.05 mm or more and 0.60 mm or less, preferably 0.10 mm or more and 0.50 mm or less, and more preferably 0.30 mm or more and 0.40 mm or less.

[0030] (4) Other Examples of materials for the metal substrate that have the above reflectivity and can obtain the above outer peripheral sag width include stainless steel (SUS), copper, and aluminum.

[0031] Furthermore, the metal substrate in the present disclosure is disc-shaped, and may be, for example, a perforated disc-shaped substrate having a central hole, or may not have a central hole. When the metal substrate is a perforated disc-shaped substrate, the outer diameter in plan view may be, for example, 15 mm or more and 20 mm or more. On the other hand, the outer diameter may be, for example, 70 mm or less and 60 mm or less. Specifically, the outer diameter may be, for example, 15 mm or more and 70 mm or less and 20 mm or more and 60 mm or less. The inner diameter is, for example, 5 mm or more and 20 mm or less. The difference between the outer diameter and the inner diameter (outer-inner diameter difference) is, for example, 8 mm or more and 13 mm or less. Within this range, waviness of the scale that occurs during punching can be suppressed.

[0032] 2.Low reflective layer The low-reflection layer in the present disclosure is provided in a pattern on the first surface side of the metal substrate along the circumferential direction of the metal substrate. In the present disclosure, the low-reflection region, which is the region where the low-reflection layer is provided, has a reflectance at any wavelength within a wavelength range of 500 nm to 1000 nm of, for example, 10% or less, or alternatively, 5% or less, or 1% or less. On the other hand, the reflectance of the low-reflection region is, for example, 0% or more. Specifically, the reflectance of the low-reflection region in the present disclosure is, for example, 0% or more and 10% or less, preferably 0% or more and 5% or less, and more preferably 0% or more and 1% or less.

[0033] The reflective optical scale for an encoder according to the present disclosure preferably does not have a low-reflection layer in a region extending from the outer peripheral surface of the metal substrate to a distance of 500 μm inward. The metal substrate in the reflective optical scale for an encoder according to the present disclosure has a peripheral sag, and the width of the sag is 500 μm or less. By not having a low-reflection layer in a region extending from the outer peripheral surface of the metal substrate to a distance of 500 μm inward, peeling and cracking of the low-reflection layer can be suppressed.

[0034] Specifically, as shown in FIG. 2(b), the distance D1 between the outer peripheral surface 1c of the metal substrate 1 and the outer peripheral surface 2c of the low-reflection layer 2 is preferably 500 μm or more, more preferably 550 μm or more, and particularly preferably 600 μm or more. If the distance D1 is within the above range, peeling and cracking of the low-reflection layer can be easily suppressed. On the other hand, the distance D1 is, for example, 1500 μm or less, preferably 1000 μm or less, and more preferably 900 μm or less. If the distance D1 is within the above range, enlargement of the size of the reflective optical scale for an encoder can be suppressed. Specifically, the distance D1 is, for example, 500 μm or more and 1500 μm or less, preferably 550 μm or more and 1000 μm or less, and more preferably 600 μm or more and 900 μm or less.

[0035] The value of the distance D1 also applies to a reflective optical scale for an encoder having a disk-shaped metal substrate having a first surface and a second surface opposite to the first surface, and a low-reflection layer arranged in a pattern along the circumferential direction of the metal substrate on the first surface side of the metal substrate.

[0036] The low-reflection layer in the present disclosure is provided on the first surface side of the metal substrate in a pattern along the circumferential direction of the metal substrate. The configuration of the low-reflection layer is not particularly limited as long as the reflectance of light incident on the low-reflection region, which is the region where the low-reflection layer is provided, is lower than the reflectance of light incident on the high-reflection region.

[0037] In the present disclosure, it is preferable for the low-reflection layer to have a three-layer structure consisting of a metal chromium film and a chromium oxide film and a chromium nitride film formed in any order on the metal chromium film from the metal substrate side. With such a low-reflection layer, the reflectance of light incident on the low-reflection region can be reduced to 10% or less, preferably 5% or less, and even 1% or less, at any wavelength within a wavelength range of 500 nm to 1000 nm. Meanwhile, the reflectance of the low-reflection region is, for example, 0% or more. Specifically, the reflectance of the low-reflection region in the present disclosure is, for example, 0% or more and 10% or less, preferably 0% or more and 5% or less, and more preferably 0% or more and 1% or less.

[0038] The reflectance of the low-reflection region preferably satisfies the above range at any angle within the range of 5° to 70° of incidence. Therefore, the difference between the reflectance in the high-reflection region and the reflectance in the low-reflection region can be increased. Furthermore, if only metallic chromium is prepared, a chromium oxide film and a chromium nitride film can be easily formed by reactive sputtering or the like. Furthermore, high-resolution patterning can be performed more easily than with a silicon oxide film.

[0039] In this specification, the phrase "a chromium oxide film and a chromium nitride film formed in any order on a metal chromium film" means that the metal chromium film, the chromium oxide film, and the chromium nitride film may be formed in this order, or the metal chromium film, the chromium nitride film, and the chromium oxide film may be formed in this order.

[0040] For example, the low-reflection layer 2 of the reflective optical scale 10 for an encoder shown in Fig. 3(a) has, from the metal substrate 1 side, a metal chromium film 2c, a chromium nitride film 2b formed on the metal chromium film 2c, and a chromium oxide film 2a formed on the chromium nitride film 2b. On the other hand, the low-reflection layer 2 of the reflective optical scale 10 for an encoder shown in Fig. 3(b) has, from the metal substrate 1 side, a metal chromium film 2c, a chromium oxide film 2a formed on the metal chromium film 2c, and a chromium nitride film 2b formed on the chromium oxide film 2a.

[0041] The outermost surface of the low reflection region is preferably the surface of a chromium oxide film or chromium nitride film of the low reflection layer, and is particularly preferably the surface of a chromium oxide film, because this can more effectively reduce the reflectance in the low reflection region.

[0042] Hereinafter, "a low-reflection layer in which a metal chromium film, a chromium nitride film, and a chromium oxide film are arranged in this order" will be referred to as a first-specification low-reflection layer, and "a low-reflection layer in which a metal chromium film, a chromium oxide film, and a chromium nitride film are arranged in this order" will be referred to as a second-specification low-reflection layer.

[0043] (1) First specification low-reflection layer The low-reflection layer of this specification has a metal chromium film, a chromium nitride film, and a chromium oxide film arranged in this order from the substrate side. A low-reflection region having the low-reflection layer of this specification can reduce the reflectance at any wavelength within the wavelength range of 500 nm to 1000 nm of light irradiated from a light source to 5% or less, particularly 0.5% or less, and the change in reflectance with wavelength is gradual, making it easy to control the reflectance. Specifically, the reflectance can be reduced to 0% or more but 5% or less, particularly 0% or more but 0.5% or less. Each layer is described in detail below.

[0044] (a) Metallic chromium film In this specification, the metal chromium film is provided on a metal substrate. The metal chromium film is a layer made of metal chromium. The metal chromium film is a layer that does not substantially transmit light irradiated from a light source, and preferably has a transmittance of 0.0% or more and 1.0% or less. The transmittance can be measured using a spectrophotometer (MPC-3100) manufactured by Shimadzu Corporation or the like. The film thickness is, for example, 40 nm or more, preferably 70 nm or more.

[0045] Here, the "thickness" of each component refers to the thickness obtained by a general measurement method. Examples of thickness measurement methods include a stylus method, in which the thickness is calculated by tracing the surface with a stylus to detect unevenness, and an optical method, in which the thickness is calculated based on the spectral reflectance spectrum. Specifically, the thickness can be measured using a stylus film thickness meter P-15 manufactured by KLA-Tencor Corporation. Note that the average value of thickness measurements taken at multiple locations on the component may also be used as the thickness.

[0046] The metal chromium film can be formed by physical vapor deposition (PVD) methods such as sputtering, ion plating, and vacuum deposition.

[0047] (b) Chromium nitride film The chromium nitride film in this specification is placed between the metallic chromium film and the chromium oxide film. Unlike chromium oxynitride and chromium oxynitride carbide, the chromium nitride film is mainly composed of chromium and nitrogen and contains substantially no impurities other than chromium and nitrogen.

[0048] The atomic ratio x of Cr to N in the chromium nitride (CrNx) film is preferably 0.4 or more and 1.1 or less.

[0049] The chromium nitride film preferably has a purity of 80% to 100% of chromium and nitrogen, with the entire film being 100 atomic %. Impurities such as hydrogen, oxygen, and carbon may be included.

[0050] The thickness of the chromium nitride film (T N ) is preferably in the range of 5 nm to 100 nm, particularly in the range of 10 nm to 80 nm. O ) in relation to the wavelength of 850 nm, T N and T O If the sum of and is 40 nm or more and the wavelength is 550 nm, T N and T OThe total of the thicknesses is preferably 20 nm or more. If the thickness is within this range, the reflectance in the low reflection region can be easily reduced to 10% or less, particularly 5% or less, compared with the case where the thickness is outside the above range. Furthermore, the thickness of the chromium nitride film (T N ) is preferably in the range of 10 nm to 80 nm, since this makes it easy to reduce the reflectance over the entire range from green to infrared (approximately 500 nm to 1000 nm).

[0051] Chromium nitride can be formed by physical vapor deposition (PVD) methods such as reactive sputtering, ion plating, and vacuum evaporation. When using reactive sputtering, nitrogen is introduced into argon (Ar) gas, and a chromium nitride film can be formed by reactive sputtering using a Cr target. In this case, the composition of the chromium nitride film can be controlled by adjusting the ratio of Ar gas to nitrogen gas.

[0052] (c) Chromium oxide film The chromium oxide film is formed on the chromium nitride film and is mainly composed of chromium and oxygen. Unlike chromium oxynitride and chromium oxynitride carbide, the chromium oxide film does not substantially contain impurities other than chromium and oxygen.

[0053] The atomic ratio y of Cr to O in the chromium oxide (CrOy) film is preferably 1.4 or more and 2.1 or less.

[0054] Specifically, the chromium oxide film has a purity of 80 to 100% of chromium and oxygen, preferably 90% to 100%, based on 100 atomic % of the entire film. Impurities such as hydrogen, nitrogen, and carbon may be contained.

[0055] The thickness of the chromium oxide film is not particularly limited, but is preferably in the range of 5 nm to 100 nm, and more preferably in the range of 10 nm to 80 nm. O ) is the thickness of the chromium nitride film (T N) is preferably in the range described in the above "(1) First specification low reflective layer (b) chromium nitride film". Furthermore, the thickness of the chromium oxide film (T O ) is preferably in the range of 10 nm or more and 65 nm or less, since this makes it easy to reduce the reflectance over the entire range from green to infrared (approximately 500 to 1000 nm).

[0056] Chromium oxide can be formed by physical vapor deposition (PVD) methods such as reactive sputtering, ion plating, and vacuum evaporation. When using reactive sputtering, oxygen is introduced into argon (Ar) gas, and a chromium oxide film can be formed by reactive sputtering using a Cr target. In this case, the composition of the chromium oxide film can be controlled by adjusting the ratio of Ar gas to oxygen gas.

[0057] (2) Second-spec low-reflection layer The low-reflection layer of this specification is composed of a metal chromium film, a chromium oxide film, and a chromium nitride film, arranged in this order from the metal substrate side. A low-reflection region having the low-reflection layer of this specification can reduce the reflectance of light irradiated from a light source at any wavelength within the range of 500 nm to 1000 nm to 5% or less, particularly to 1% or less. Specifically, the reflectance can be reduced to 0% or more but 5% or less, particularly to 0% or more but 1% or less. Each layer is described in detail below.

[0058] (a) Metallic chromium film The metal chrome film in this specification is formed on a substrate. The details of the metal chrome film are the same as those in "(1) Low-reflection layer of the first specification (a) Metal chrome film" above, so the explanation will be omitted here.

[0059] (b) Chromium oxide film The chromium oxide film in this specification is disposed between the metal chromium film and the chromium nitride film. The film thickness is not particularly limited, but is preferably within a range of 5 nm to 60 nm, and particularly 10 nm to 50 nm. Furthermore, it preferably satisfies the relationship with the film thickness of the chromium nitride film described below. This is because it can more reliably reduce the reflectance at any wavelength within the low-reflectivity wavelength range of 500 nm to 1000 nm to 10% or less, particularly 5% or less.

[0060] Furthermore, the thickness of the chromium oxide film (T O ) is preferably in the range of 5 nm to 35 nm, since this makes it easy to reduce the reflectance over the entire range from green to infrared (about 500 to 1000 nm).

[0061] Other details of the physical properties, composition and formation method of the chromium oxide film are the same as those in "(1) First specification low reflective layer (c) chromium oxide film" described above, and therefore will not be described here.

[0062] (c) Chromium nitride film The chromium nitride film of this specification is formed on a chromium oxide film. The thickness of the chromium nitride film of this specification is not particularly limited, but is preferably in the range of 5 nm to 100 nm, and more preferably in the range of 10 nm to 80 nm. Furthermore, the thickness of the chromium oxide film (T O ) in relation to the wavelength of 850 nm, T N and T O If the sum of is 30 nm or more and the wavelength is 550 nm, T N and T O The total thickness of the chromium nitride film (T N ) is preferably in the range of 10 nm or more and 60 nm or less, since this makes it easy to reduce the reflectance over the entire range from green to infrared (approximately 500 nm or more and 1000 nm or less).

[0063] The method for forming the low-reflection layer in the present disclosure is not particularly limited, but it can be manufactured by selective etching or lift-off. Specifically, a metal chromium film is formed on a metal substrate by, for example, a sputtering method, and then a chromium nitride film and a chromium oxide film are formed. Next, the metal chromium film, the chromium nitride film, and the chromium oxide film are patterned by photolithography and etching, thereby manufacturing a patterned low-reflection layer.

[0064] Alternatively, a resist pattern may be formed on a metal substrate, and a metal chromium film, a chromium nitride film, and a chromium oxide film may be formed by a known vacuum film-forming method such as sputtering.The resist pattern may then be removed to lift off the metal chromium film, the chromium nitride film, and the chromium oxide film formed directly on the resist pattern, thereby obtaining patterns of the chromium nitride film and the chromium oxide film.

[0065] In the present disclosure, the low-reflectivity region has a reflectance at any wavelength within a wavelength range of 500 nm or more and 1000 nm or less of, for example, 10% or less, or alternatively 5% or less, or 1% or less. Specifically, the reflectance of the low-reflection region in the present disclosure is, for example, 0% or more and 10% or less, preferably 0% or more and 5% or less, and more preferably 0% or more and 1% or less. The reflectance of the low-reflection region preferably satisfies the above range at any angle of incidence within a range of 5° or more and 70° or less. The outermost surface of the low-reflection region is preferably the surface of a chromium oxide film or chromium nitride film of the low-reflection layer, and particularly preferably the surface of a chromium oxide film. This is because the reflectance in the low-reflection region can be more effectively reduced.

[0066] 3. Other layer configurations The reflective optical scale for an encoder according to the present disclosure may have other layers in addition to the metal substrate and the low-reflection layer. For example, the reflective optical scale for an encoder according to the present disclosure may have a protective layer between the metal substrate and the low-reflection layer.

[0067] The protective layer preferably has transparency and a function of protecting the metal substrate. By providing the protective layer, there is no risk that the surface of the metal substrate will become rough and increase in surface roughness during etching when forming the low-reflection layer in a pattern. Therefore, diffuse reflection of light can be suppressed. The protective layer may be provided over the entire area of ​​the metal substrate in a plan view, or may be provided in a partial area.

[0068] The material for the protective layer is not particularly limited as long as it is transparent and can protect the highly reflective layer, and may be either an organic material or an inorganic material.

[0069] The organic material preferably contains a resin. The resin used in the protective layer is not particularly limited as long as it can provide a transparent protective layer. Examples include ionizing radiation-curable resins that are cured by exposure to ionizing radiation such as ultraviolet light or electron beams, and thermosetting resins that are cured by heating. Specific examples include novolac resins, polyolefin resins, polyester resins, urethane resins, polyimide resins, acrylic resins, and epoxy resins. Among novolac resins, phenol novolac resins are preferred because they have excellent electrical properties and can suppress problems caused by static electricity. Among acrylic resins, trifunctional or higher acrylates such as pentaerythritol tetraacrylate and dipentaerythritol tetraacrylate are preferred because they can enhance photocurability. Among epoxy resins, epoxy acrylate resins having a fluorene structure are preferred because they improve heat resistance, adhesion, and chemical resistance. Among epoxy resins, cardo epoxy resins are also preferred because they can impart excellent transparency, heat resistance, surface hardness, and flatness. The organic material may contain, in addition to the resin, a polymerization initiator, various additives, and the like.

[0070] Examples of inorganic materials include inorganic compounds. Examples of inorganic compounds include oxides, oxynitrides, nitrides, oxycarbides, and oxycarbonitrides of metal elements or nonmetal elements such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, titanium, boron, yttrium, zirconium, cerium, and zinc. Silicon dioxide (SiO2) is particularly preferred. The inorganic compounds may be used alone or in combination in any proportion.

[0071] 4. Reflective optical scale for encoders The reflective optical scale for an encoder according to the present disclosure is typically used as an optical scale for a rotary encoder. The reflective optical scale for an encoder is disc-shaped, and may be, for example, a perforated disc with a center hole or may not be provided with a center hole. When the reflective optical scale for an encoder according to the present disclosure is disc-shaped with a hole, the outer diameter in plan view may be, for example, 15 mm or more and 20 mm or more. On the other hand, the outer diameter may be, for example, 70 mm or less and 60 mm or less. Specifically, the outer diameter may be, for example, 15 mm or more and 70 mm or less and 20 mm or more and 60 mm or less. The inner diameter is, for example, 5 mm or more and 20 mm or less. The difference between the outer diameter and the inner diameter (outer-inner diameter difference) is, for example, 8 mm or more and 13 mm or less. Within this range, waviness of the scale that occurs during punching can be suppressed.

[0072] Furthermore, the reflective optical scale for an encoder according to the present disclosure can be manufactured by the "C. Manufacturing method of a reflective optical scale for an encoder" described below.

[0073] B. Reflective optical encoder The present disclosure provides a reflective optical encoder comprising the above-mentioned reflective optical scale for an encoder, a light source that irradiates measurement light onto the surface of the reflective optical scale for an encoder on which the low-reflection layer is arranged, and a photodetector that detects reflected light from the reflective optical scale for an encoder.

[0074] Fig. 4 is a schematic perspective view showing an example of a reflective optical encoder including a reflective optical scale for an encoder according to the present disclosure. The reflective optical encoder 100 according to the present disclosure includes a reflective optical scale for an encoder 10, and further includes a light source 21 and a photodetector 22. In Fig. 4, a fixed slit 23 is arranged between the photodetector 22 and the reflective optical scale for an encoder 10. The encoder according to the present disclosure has a reflective optical scale for an encoder with reduced peripheral sagging as described above, and therefore has cost advantages for the reasons described above, and also has good encoder characteristics because peeling and cracking of the low-reflection layer can be suppressed.

[0075] 1. Reflective optical scale for encoders The reflective optical scale for an encoder is the same as that described above in "A. Reflective optical scale for an encoder," and therefore will not be described here.

[0076] 2.Light source The light source may be, for example, an LED (light emitting diode) or a laser. The wavelength λ of the light emitted from the light source is, for example, in the green to infrared range (approximately 500 nm to 1000 nm). The angle of incidence of the light on the optical scale 10 is, for example, 5° to 70°.

[0077] 3. Photodetector The photodetector detects light reflected by the optical scale and includes a light receiving element (e.g., a photoelectric conversion element) such as a photodiode or an imaging element.

[0078] 4.Other The reflective optical encoder according to the present disclosure may include a fixed slit between the photodetector and the reflective optical scale for the encoder. By providing the fixed slit, the change in the amount of light received by the photodetector increases, thereby improving detection sensitivity. The fixed slit may be provided between the light source and the reflective optical scale for the encoder.

[0079] C. Manufacturing method of reflective optical scale for encoder The present disclosure provides a method for manufacturing a reflective optical scale for an encoder, comprising: a step of producing a multi-sided body having a metal substrate to be processed, the metal substrate having a first surface and a second surface opposite the first surface, the reflectivity of at least the first surface being 50% or more, and a thickness of 0.05 mm or more and 0.60 mm or less, and patterned low-reflection layers arranged in a circular pattern and multi-sidedly attached to the first surface side of the metal substrate to be processed, the multi-sided body having planned peripheral punching lines for the reflective optical scale for an encoder formed outside the outer peripheral surfaces of each of the low-reflection layers; and a singulation step of obtaining the reflective optical scale for an encoder by punching out the multi-sided body along the planned peripheral punching lines to singulate it.

[0080] 5 is a schematic top view of a polygonal body 50 produced in the polygonal body production step. The polygonal body 50 in the present disclosure has a metal substrate 51 to be processed, at least a first surface of which has a reflectance equal to or greater than a predetermined value and a thickness within a predetermined range, and circumferentially arranged patterned low-reflection layers 2 that are multiply attached to the first surface side of the metal substrate 51 to be processed. In the polygonal body 50 in the present disclosure, a planned outer periphery punching line L for the reflective optical scale for an encoder is formed on the outside of each low-reflection layer 2. In the singulation step, the polygonal body 50 is singulated by punching along the planned outer periphery punching line L, thereby obtaining a reflective optical scale for an encoder.

[0081] 1. Multi-faceted body manufacturing process In this process, a multi-faceted body is produced which has a metal substrate to be processed, at least the first surface of which has a reflectivity of 50% or more and a thickness of 0.05 mm or more and 0.60 mm or less, and patterned low-reflection layers arranged in a circular pattern and multi-faceted on the first surface side of the metal substrate to be processed, with planned peripheral punching lines for a reflective optical scale for an encoder formed outside the outer peripheral surface of each low-reflection layer.

[0082] The reflectance and thickness of the first surface of the metal substrate to be processed are the same as those of the first surface of the metal substrate described above. The size of the metal substrate to be processed in plan view is not particularly limited as long as it is large enough to allow the patterned low-reflection layer to be attached to multiple surfaces.

[0083] The low-reflection layer is the same as the low-reflection layer described above in "A. Reflective optical scale for encoder." The method for applying a patterned low-reflection layer to the first surface of the metal substrate to be processed is the same as the method for forming a low-reflection layer described above in "A. Reflective optical scale for encoder."

[0084] As shown in FIG. 5 , in the polygonal body according to the present disclosure, a planned peripheral punching line L for the reflective optical scale for an encoder is formed outside the outer peripheral surface of each low-reflection layer 2. The distance D2 between the planned peripheral punching line L for the reflective optical scale for an encoder and the outer peripheral surface of the low-reflection layer 2 is preferably 500 μm or more, more preferably 550 μm or more, and particularly preferably 600 μm or more. If the distance D2 is within the above range, peripheral sagging is unlikely to occur in the region where the low-reflection layer is formed during punching, thereby preventing peeling and cracking of the low-reflection layer. On the other hand, the distance D2 is, for example, 1500 μm or less, preferably 1000 μm or less, and more preferably 900 μm or less. If the distance D2 is within the above range, it is possible to prevent the size of the reflective optical scale for an encoder from increasing. Specifically, the distance D2 is, for example, 500 μm or more and 1500 μm or less, preferably 550 μm or more and 1000 μm or less, and more preferably 600 μm or more and 900 μm or less.

[0085] In addition, a polygonal body for manufacturing a perforated disk-shaped reflective optical scale for an encoder may have an inner peripheral planned punching line formed thereon for punching out a central hole in the reflective optical scale for an encoder.

[0086] 2.Singulation process In this step, the polygonal body produced in the polygonal body production step is punched out along the planned outer peripheral punching lines to separate it into individual pieces, thereby obtaining a reflective optical scale for an encoder.

[0087] FIG. 6 is a schematic diagram showing an example of a punching device used in the singulation step in the manufacturing method for a reflective optical scale for an encoder according to the present disclosure. As shown in FIGS. 6(a) and 6(b), the multifaceted polygonal body 50 is placed on a lower stage 62 having a lower blade 61. The lower stage 62 is then moved upward, and the upper stage 63 having an upper blade 64 is moved downward, and the polygonal body 50 is punched out to obtain individual reflective optical scales for encoders 10. At this time, the upper blade is aligned with the outer peripheral planned driving lines and the inner peripheral planned driving lines. It is also preferable to position a metal substrate pressing member 65 opposite the upper blade 64. The pressing member 65 clamps the metal substrate together with the upper blade 64 during punching, enabling punching with minimal burrs and sagging.

[0088] In the present disclosure, the clearance width in this process is, for example, 0.020 mm or less, preferably 0.017 mm or less, and more preferably 0.015 mm or less, thereby making it easy to keep the width of the peripheral sag of the reflective optical scale for an encoder within the above range. Meanwhile, the clearance width is, for example, 0.003 mm or more, preferably 0.004 mm or more, and more preferably 0.006 mm or more. Having the clearance width within the above range reduces the load on the blade of the punching device. The clearance width refers to the widthwise distance C between the end face of the upper blade 64 and the end face of the lower blade 61, as shown in FIG. 6(b). Specifically, the clearance width is, for example, 0.003 mm or more and 0.020 mm or less, preferably 0.004 mm or more and 0.017 mm or less, and more preferably 0.006 mm or more and 0.015 mm or less.

[0089] The reflective optical scale for an encoder obtained in this step is the same as the reflective optical scale for an encoder described above in "A. Reflective optical scale for an encoder."

[0090] D. Reflective optical scale multi-faceted body for encoder The present disclosure provides a polygonal reflective optical scale body for an encoder, which comprises a metal substrate to be processed having a first surface and a second surface opposite the first surface, with the reflectivity of at least the first surface being 50% or more and a thickness of 0.05 mm or more and 0.60 mm or less, and patterned low-reflection layers arranged in a circular pattern and attached to the first surface side of the metal substrate to be processed, in which a planned outer peripheral punching line for the reflective optical scale for an encoder is formed outside the outer peripheral surface of each of the low-reflection layers, and the distance between the planned outer peripheral punching line of the reflective optical scale for an encoder and the outer peripheral surface of the low-reflection layer is 500 μm or more and 1500 μm or less.

[0091] According to the polygonal reflective optical scale body for an encoder of the present disclosure, the distance between the planned peripheral punching line of the reflective optical scale for an encoder and the peripheral surface of the low-reflection layer is within a predetermined range, so that peripheral sagging that occurs during punching is less likely to extend to the area where the low-reflection layer is formed, thereby suppressing peeling and cracking of the low-reflection layer and also suppressing an increase in the size of the reflective optical scale for an encoder.

[0092] The reflective optical scale polygonal body for an encoder of the present disclosure is similar to the content described above in "C. Manufacturing method of a reflective optical scale for an encoder," and therefore description thereof will be omitted here.

[0093] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0094] The present disclosure will be further explained below with reference to experimental examples.

[0095] (Experimental Example 1-1) A 0.3 mm thick SUS substrate was prepared. Using the punching device shown in Figure 6, the SUS substrate was punched to obtain a perforated disk-shaped SUS substrate with an outer diameter of 23.5 mm and an inner diameter of 15.0 mm. The clearance width C was set to 0.004 mm. The width of the peripheral sagging of the resulting perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(a).

[0096] (Experimental Example 1-2) In addition, a perforated disk-shaped SUS substrate was obtained in the same manner as in Experimental Example 1-1, except that the clearance width was changed to 0.015 mm. The width of the peripheral sagging of the obtained perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(a).

[0097] (Experimental Example 1-3) A perforated disk-shaped SUS substrate was obtained in the same manner as in Experimental Example 1-1, except that the thickness of the SUS substrate to be processed was changed to 0.4 mm. The width of the peripheral sagging of the obtained perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(a).

[0098] (Experimental Example 1-4) A perforated disk-shaped SUS substrate was obtained in the same manner as in Experimental Example 1-1, except that the thickness of the SUS substrate to be processed was changed to 0.4 mm and the clearance width was changed to 0.009 mm. The width of the peripheral sagging of the obtained perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(a).

[0099] (Experimental Example 1-5) A perforated disk-shaped SUS substrate was obtained in the same manner as in Experimental Example 1, except that the thickness of the SUS substrate to be processed was changed to 0.4 mm and the clearance width was changed to 0.012 mm. The width of the peripheral sagging of the obtained perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(a).

[0100] (Experimental Example 1-6) A perforated disk-shaped SUS substrate was obtained in the same manner as in Experimental Example 1, except that the thickness of the SUS substrate to be processed was changed to 0.4 mm and the clearance width was changed to 0.015 mm. The width of the peripheral sagging of the obtained perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(a).

[0101] 7(a), it was confirmed that the width of the peripheral sag did not change depending on the width of the clearance. On the other hand, when Experimental Examples 1-1 and 1-2 were compared with Experimental Examples 1-3 to 1-6, it was confirmed that the thicker the metal base material, the larger the width of the peripheral sag.

[0102] (Experimental Example 2-1) A 0.3 mm thick SUS substrate was prepared. Using the punching device shown in Figure 6, the SUS substrate was punched to obtain a perforated disk-shaped SUS substrate with an outer diameter of 23.5 mm, an inner diameter of 15.0 mm, and a difference between the outer and inner diameters of 8.5 mm. The width of the peripheral sagging of the resulting perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(b).

[0103] (Experimental Example 2-2) Using the same method as in Experimental Example 2-1, a perforated disk-shaped SUS substrate with an outer diameter of 21.96 mm, an inner diameter of 9.16 mm, and a difference between the outer and inner diameters of 12.8 mm was obtained. The width of the peripheral sagging of the obtained perforated disk-shaped SUS substrate was measured. The results are shown in Figure 7(b).

[0104] (Experimental Example 2-3) A perforated disk-shaped SUS substrate with an outer diameter of 23.5 mm, an inner diameter of 15.0 mm, and an outer / inner diameter difference of 8.5 mm was obtained in the same manner as in Experimental Example 2-1, except that the thickness of the SUS substrate to be processed was 0.4 mm. The width of the peripheral sagging of the obtained SUS substrate was measured. The results are shown in Figure 7(b).

[0105] (Experimental Example 2-4) A perforated disk-shaped SUS substrate with an outer diameter of 25.3 mm, an inner diameter of 13.8 mm, and a difference in outer and inner diameters of 11.5 mm was obtained in the same manner as in Experimental Example 2-1, except that the thickness of the SUS substrate to be processed was 0.4 mm. The width of the peripheral sagging of the obtained SUS substrate was measured. The results are shown in Figure 7(b).

[0106] (Experimental Example 2-5) A perforated disk-shaped SUS substrate with an outer diameter of 21.96 mm, an inner diameter of 9.16 mm, and a difference in outer and inner diameters of 12.8 mm was obtained in the same manner as in Experimental Example 2-1, except that the thickness of the SUS substrate to be processed was 0.4 mm. The width of the peripheral sagging of the obtained SUS substrate was measured. The results are shown in Figure 7(b).

[0107] From the results in Figure 7(b), it was confirmed that the peripheral sagging is not dependent on the difference between the outer and inner diameters of the SUS substrate. On the other hand, it was confirmed that the thicker the metal substrate, the larger the peripheral sagging.

[0108] That is, the present disclosure provides the following inventions. [1] A reflective optical scale for an encoder comprising: a disk-shaped metal substrate having a first surface and a second surface opposite to the first surface; and a low-reflection layer arranged in a pattern along the circumferential direction of the metal substrate on the first surface side of the metal substrate, wherein the metal substrate has a reflectivity of at least the first surface of 50% or more, a thickness of 0.05 mm or more and 0.60 mm or less, and the metal substrate has a sagging on the outer peripheral edge on the first surface side, and the width of the sagging is 500 μm or less.

[0109] [2] The reflective optical scale for an encoder according to [1], wherein the metal substrate is a SUS substrate.

[0110] [3] The reflective optical scale for an encoder according to [1] or [2], wherein the metal substrate is a perforated disk having a central hole.

[0111] [4] The reflective optical scale for an encoder according to [3], wherein the metal substrate has a sag on the inner peripheral edge on the first surface side, and the width of the sag is 500 μm or less.

[0112] [5] The reflective optical scale for an encoder according to [3] or [4], wherein the difference between the outer and inner diameters of the perforated disk-shaped metal substrate is 8 mm or more and 13 mm or less.

[0113] [6] A reflective optical scale for an encoder described in any of [1] to [5], wherein the ratio (T2 / T1) of the thickness T2 at the outer peripheral end of the metal substrate to the thickness T1 of the metal substrate is 0.70 or more and 0.90 or less.

[0114] [7] A reflective optical scale for an encoder described in any one of [1] to [6], wherein the distance D1 between the outer peripheral surface of the metal substrate and the outer peripheral surface of the low-reflection layer is 500 μm or more and 1500 μm or less.

[0115] [8] The reflective optical scale for an encoder according to any one of [1] to [7], wherein the metal substrate has a sagging amount of 10 μm or more and 500 μm or less.

[0116] [9] a disk-shaped metal substrate having a first surface and a second surface opposite to the first surface; A reflective optical scale for an encoder having a low-reflection layer arranged in a pattern along the circumferential direction of the metal substrate on the first surface side of the metal substrate, wherein the distance D1 between the outer peripheral surface of the metal substrate and the outer peripheral surface of the low-reflection layer is 500 μm or more and 1500 μm or less.

[0117]

[10] A reflective optical encoder comprising: a reflective optical scale for an encoder according to any one of [1] to [9]; a light source that irradiates measurement light onto the surface of the reflective optical scale for an encoder on which the low-reflection layer is disposed; and a photodetector that detects reflected light from the reflective optical scale for an encoder.

[0118]

[11] A method for manufacturing a reflective optical scale for an encoder, comprising: a step of producing a multi-faceted body having a metal substrate to be processed, the metal substrate having a first surface and a second surface opposite the first surface, the reflectivity of at least the first surface being 50% or more, and a thickness of 0.05 mm or more and 0.60 mm or less, and a patterned low-reflection layer arranged in a circular pattern and multi-faceted on the first surface side of the metal substrate to be processed, the patterned low-reflection layer having planned outer peripheral punching lines for the reflective optical scale for an encoder formed outside the outer peripheral surface of the low-reflection layer; and a singulation step of obtaining the reflective optical scale for an encoder by punching out the multi-faceted body along the planned outer peripheral punching lines.

[0119]

[12] A polygonal reflective optical scale body for an encoder, comprising: a metal substrate to be processed having a first surface and a second surface opposite the first surface, wherein the reflectivity of at least the first surface is 50% or more and the thickness is 0.05 mm or more and 0.60 mm or less; and a patterned low-reflection layer arranged in a circular shape and attached to the first surface side of the metal substrate to be processed in a polygonal manner, wherein a planned outer peripheral punching line for the reflective optical scale for an encoder is formed outside the outer peripheral surface of the low-reflection layer, and the distance between the planned outer peripheral punching line of the reflective optical scale for an encoder and the outer peripheral surface of the low-reflection layer is 500 μm or more and 1500 μm or less. [Explanation of symbols]

[0120] 1 … Metal base material 2…Low reflective layer P... Who 10... Reflective optical scale for encoder 50... Reflective optical scale multi-faceted body for encoder 100... Reflective optical encoder

Claims

1. a disk-shaped metal substrate having a first surface and a second surface opposite to the first surface; a low-reflection layer disposed on the first surface side of the metal substrate in a pattern along a circumferential direction of the metal substrate, the metal base has a reflectance of at least 50% on the first surface side and a thickness of 0.05 mm or more and 0.60 mm or less; the metal base has a sagging on the outer peripheral edge on the first surface side, and the width of the sagging is 500 μm or less; the metal substrate is a perforated disk having a central hole, The difference between the outer and inner diameters of the perforated disk-shaped metal substrate is 8 mm or more and 13 mm or less, A reflective optical scale for an encoder, wherein the ratio (T2 / T1) of the thickness T2 at the outer peripheral edge of the metal substrate to the thickness T1 of the metal substrate is 0.70 or more and 0.90 or less.

2. 2. The reflective optical scale for an encoder according to claim 1, wherein the metal substrate is a stainless steel substrate.

3. 2. The reflective optical scale for an encoder according to claim 1, wherein the metal substrate has a sag on an inner peripheral edge on the first surface side, and the width of the sag is 500 μm or less.

4. 2. The reflective optical scale for an encoder according to claim 1, wherein a distance D1 between an outer peripheral surface of the metal substrate and an outer peripheral surface of the low-reflection layer is 500 μm or more and 1500 μm or less.

5. 2. The reflective optical scale for an encoder according to claim 1, wherein the metal substrate has a sagging amount of 10 μm or more and 500 μm or less.

6. A reflective optical scale for an encoder according to any one of claims 1 to 5; a light source that irradiates a measurement light onto a surface of the reflective optical scale for an encoder on which the low-reflection layer is disposed; and a photodetector that detects reflected light from the reflective optical scale for the encoder.

Images