CN113124750A - Reflection plate for optical encoder and method for manufacturing same - Google Patents
Reflection plate for optical encoder and method for manufacturing same Download PDFInfo
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- CN113124750A CN113124750A CN201911388728.5A CN201911388728A CN113124750A CN 113124750 A CN113124750 A CN 113124750A CN 201911388728 A CN201911388728 A CN 201911388728A CN 113124750 A CN113124750 A CN 113124750A
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
Abstract
Provided are a reflection plate for an optical encoder, which can be manufactured at a lower cost than conventional reflection plates and has a position measurement accuracy higher than conventional reflection plates, and a method for manufacturing the reflection plate. The optical encoder reflecting plate (1) is a disk-shaped thin plate (11) having a bearing hole (12) formed in the center of the surface thereof and a plurality of narrow strip-shaped non-reflecting sections (13) arranged in a radial pattern with the bearing hole (12) as the center. The sheet (11) has a multilayer structure including a resin layer (111) made of a PET film, a metal layer (112) made of specular aluminum, and a metal protective layer (113) made of an acrylic resin paint, and the non-reflective portion (13) is black ink (I) formed on the metal protective layer (113) or the resin layer (111) in a thickness of 1 to 4 [ mu ] m by an offset method. The sheet (11) is formed by a PET film formed by aluminum deposition as a base material, and the non-reflection part (13) is formed by an offset method, so that the sheet has a shape accuracy and a measurement accuracy equal to or higher than those of the conventional sheet.
Description
Technical Field
The present invention relates to a reflection plate for an optical encoder used for detecting a displacement of an object by reflecting incident light and receiving the light, and a method for manufacturing the same.
Background
In a conventional reflection plate 100 for an optical encoder, as shown in fig. 5, a strip (slit)102 is formed by plating a flat plate 101, which is made of a metal such as stainless steel or nickel and has a mirror-finished surface, with black chrome or copper (see, for example, patent documents 1 and 2). In use, the narrow strip 102 absorbs light, while the portion other than the narrow strip 102 reflects and receives the light, thereby enabling measurement of the displacement of the object.
Here, the optical encoder reflecting plate 100 is used in a large amount in a control machine, a measuring instrument, and the like, and therefore needs to be manufactured at a low cost as much as possible, but the conventional manufacturing method and configuration have a problem that the cost increases in mass production because the manufacturing process is complicated although the shape accuracy and the position measurement accuracy of the narrow strip 102 are good.
When the narrow strip 102 is formed in this way, a step is generated between the narrow strip and the circular plate 101, and thus there is a problem that the incident light is irregularly reflected due to the step, and the measurement accuracy is lowered.
On the other hand, the following structure is also available: a narrow groove is formed in a base material, and copper is embedded in the groove and polished to eliminate a difference in height between the narrow groove and a disk (see, for example, patent document 2).
However, even with this method, it is difficult to completely eliminate the difference in height between the narrow strip and the circular plate, and there is a risk that the glossy surface is damaged during polishing, thereby impairing the light reflectivity.
On the other hand, when other manufacturing methods and configurations are studied to reduce manufacturing costs, a problem arises in that the shape accuracy and the position measurement accuracy of the narrow strip 102 are reduced. For example, it is conceivable to print black ink on the glossy surface to form a narrow stripe 102 instead of plating black chrome or plating copper. In this regard, in the case of employing the screen printing method, the coating thickness of the ink depends on the thickness of the screen, and therefore, it generally reaches several tens μm or more, and therefore, the above-described reduction in the position measurement accuracy due to the spurious reflection cannot be avoided. On the other hand, although the method of drawing the narrow strip 102 with ink by the ink jet method can be certainly formed thinly, the printing speed is relatively slow, and therefore, there is a problem that the productivity is lowered and the manufacturing cost is increased.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 5925365
Patent document 2: japanese patent laid-open publication No. 2004-151076
Disclosure of Invention
Problems to be solved by the invention
In view of the above, an object of the present invention is to provide a reflection plate for an optical encoder, which has shape accuracy and position measurement accuracy equal to or higher than those of a conventional reflection plate for an optical encoder, and which is lower in cost than the conventional reflection plate for an optical encoder, and a method for manufacturing the same.
Means for solving the problems
In order to achieve the above object, the invention according to claim 1 is a reflection plate for an optical encoder for measuring a position of an object, the reflection plate comprising: a disc-shaped thin plate; a bearing hole formed in the center of the surface of the thin plate; and a plurality of narrow-stripe-shaped non-reflective portions arranged in a radial pattern around the bearing hole, wherein the thin plate has a multilayer structure in which a resin layer, a metal layer, and a metal protective layer are sequentially laminated, the non-reflective portions are formed in close contact with the metal protective layer, the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portions are formed of black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portions in the longitudinal direction is a difference of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portions is less than 10%, and the thickness of the non-reflective portions is 1 to 4 μm.
The invention described in claim 2 is a reflection plate for an optical encoder for measuring a position of an object, the reflection plate for an optical encoder comprising a rectangular thin plate and a plurality of narrow strip-shaped non-reflection portions arranged in a predetermined pattern in a surface of the thin plate, the thin plate having a multilayer structure in which a resin layer, a metal layer, and a metal protective layer are sequentially laminated, the non-reflection portions being formed on the metal protective layer in close contact with each other in a direction substantially perpendicular to a longitudinal direction of the thin plate, the metal protective layer being formed of a transparent resin having a light transmittance of 95% or more, the metal layer being formed of a glossy metal having a light reflectance of 60% or more, the non-reflection portions being formed of a black ink dedicated to gravure offset printing, and dimensional accuracies of a length and a width of the non-reflection portions in the longitudinal direction being a difference of ± 3 μm or less with respect to a size of a concave portion of a gravure plate, the light reflectivity of the non-reflection part is less than 10%, and the thickness of the non-reflection part is 1-4 mu m.
The invention described in claim 3 is a reflection plate for an optical encoder for measuring a position of an object, the reflection plate comprising: a disc-shaped thin plate; a bearing hole formed in the center in the plane of the thin plate; and a non-reflection portion having a plurality of narrow-stripe-shaped openings arranged in a radial line in a predetermined pattern with the bearing hole as a center; the thin plate is of a multilayer structure in which a resin layer, a metal layer, and a metal protective layer are sequentially stacked, the non-reflective portion is formed on the metal protective layer in a close contact manner, the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is a difference of ± 3 μm or less with respect to the size of a recess of a gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
The invention described in claim 4 is a method for manufacturing a reflection plate for an optical encoder for measuring a position of an object, the method including: coating a metal protective layer with a uniform thickness on the glossy surface of a metal layer of a resin sheet comprising the resin layer having the metal layer with the glossy surface formed with the uniform thickness in the surface to form a multilayer film; forming a non-reflective portion on the metal protective layer of the resin sheet by radially printing a black ink dedicated for gravure offset printing in a predetermined pattern by a gravure offset method; drying and curing the black ink under a predetermined condition; forming a bearing hole with a focal point portion of the radiation depicted by the non-reflection portion as a center; and cutting the resin sheet into a disc shape with a predetermined radius with the center of the bearing hole as the center, wherein the metal protective layer is formed by transparent resin with the light transmittance of more than 95%, the metal layer is formed by glossy metal with the light reflectance of more than 60%, the non-reflection part is formed by black ink special for gravure offset printing, the dimensional accuracy of the length and the width of the non-reflection part in the length direction is within a range of ± 3 μm relative to the size of the concave part of the gravure plate, the light reflectance of the non-reflection part is less than 10%, and the thickness of the non-reflection part is 1-4 μm.
The invention described in claim 5 is a method for manufacturing a reflection plate for an optical encoder for measuring a position of an object, the method including: forming a resin layer, and coating a metal protective layer with a uniform thickness on the glossy surface of a metal layer of a resin sheet comprising the resin layer on which the metal layer having the glossy surface is formed with a uniform thickness in a surface of the resin layer to form a multilayer film; printing, by a gravure offset method, a black ink dedicated to gravure offset printing in a layer shape in which openings in a radial line shape are formed in a predetermined pattern on the metal protective layer of the resin sheet, thereby forming a non-reflective portion; drying and curing the black ink under a predetermined condition; forming a bearing hole with a focal portion of the radiation depicted by the opening as a center; and cutting the resin sheet into a disc shape with a predetermined radius with the center of the bearing hole as the center, wherein the metal protective layer is formed by transparent resin with the light transmittance of more than 95%, the metal layer is formed by glossy metal with the light reflectance of more than 60%, the non-reflection part is formed by black ink special for gravure offset printing, the dimensional accuracy of the length and the width of the non-reflection part in the length direction is within a range of ± 3 μm relative to the size of the concave part of the gravure plate, the light reflectance of the non-reflection part is less than 10%, and the thickness of the non-reflection part is 1-4 μm.
The invention described in claim 6 is a method for manufacturing a reflection plate for an optical encoder for measuring a position of an object, the method including: coating a metal protective layer with a uniform thickness on the glossy surface of a metal layer of a resin sheet comprising the resin layer having the metal layer with the glossy surface formed with the uniform thickness in the surface to form a multilayer film; printing black ink dedicated to gravure offset printing substantially in parallel in a predetermined pattern on the metal protective layer of the resin sheet by an offset method to form a non-reflective portion; drying and curing the black ink under a predetermined condition; and cutting the resin sheet into a rectangular shape with a predetermined width such that a long side thereof is oriented in a direction substantially perpendicular to the non-reflective portion, wherein the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is a difference of ± 3 μm or less with respect to the size of the recess of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
Effects of the invention
According to the inventions described in claims 1 to 3, since the thin plate is formed of a multilayer structure of the glossy metal and the resin, the thin plate has a light reflectance equal to or higher than that of a conventional structure made of only a metal, and the manufacturing cost can be kept low. Further, since the non-reflective portion is a black ink dedicated for offset printing formed by an offset method, the shape accuracy is equal to or higher than that in the case of manufacturing by a conventional electroforming method, the position measurement accuracy can be higher than that in the conventional case, and the manufacturing cost can be further reduced. In addition, the metal protective layer can prevent the metal layer from being damaged or deteriorated and can ensure the adhesion of the black ink. Further, since the height difference between the non-reflective portion and the resin layer or the metal protective layer is smaller than that in the conventional art, the irregular reflection of the incident light can be suppressed.
According to the inventions described in claims 4 to 6, since the thin plate having a multilayer structure of the bright metal and the resin is processed into a predetermined shape, the light reflectance is equal to or higher than that in the case of the production by the conventional electroforming method, and the production cost can be kept low. Further, since the non-reflective portion is formed by printing black ink dedicated for offset printing by an offset method, the shape accuracy is equal to or higher than that of the conventional electroforming method, the position measurement accuracy can be higher than that of the conventional method, and the manufacturing cost can be further reduced. Further, the non-reflective portion can be formed with a smaller thickness and with improved shape accuracy and productivity as compared with the case where another printing method such as a screen printing method is used or the case where ink for another printing method is used.
Drawings
Fig. 1 is a schematic front view (a) and a side sectional view (b) of a reflection plate for an optical encoder according to an embodiment of the present invention.
Fig. 2 is a schematic process diagram for manufacturing a reflection plate for an optical encoder according to an embodiment of the present invention.
Fig. 3 is a schematic front view (a) and a side sectional view (b) of a reflection plate for an optical encoder according to another embodiment of the present invention.
Fig. 4 is a schematic front view of a reflection plate for an optical encoder according to another embodiment of the present invention.
Fig. 5 is a schematic front view (a) and a schematic side view (b) of a conventional reflection plate for an optical encoder.
Description of the reference numerals
1. 2, 3 optical encoder reflecting plate
11. 21 thin plate
111. 211 resin layer
112. 212 metal layer
113. 213 protective metal layer
12 bearing hole
13. 22, 31 non-reflection part
D ink plate
I ink
S scraper
G intaglio
B rubber cloth
Detailed Description
Embodiments of the present invention will be described with reference to the attached drawings. In the drawings, the size, the interval, the number, and other details of the structure of each part in the drawings are greatly simplified and omitted from actual objects in order to facilitate recognition and understanding.
Fig. 1 is a schematic front view (a) and a side sectional view (b) of a reflection plate 1 for an optical encoder according to an embodiment.
The reflection plate 1 for an optical encoder includes: a disc-shaped thin plate 11; a circular bearing hole 12 formed in the center of the thin plate 11; and narrow-stripe-shaped non-reflection portions 13 arranged in a radial pattern concentrically with the bearing holes 12 on one surface of the thin plate 11.
The sheet 11 has a multilayer structure in which a resin layer 111, a metal layer 112, and a metal protective layer 113 are stacked in this order, and the layers are in close contact with each other with a force not less than a degree that causes interlayer peeling.
The resin layer 111 is a resin capable of maintaining transparency, such as PET, polyimide, acrylic, polyurethane, polycarbonate, and vinyl chloride, having a thickness of 100 μm or more, and in the present embodiment, a 188 μm thick PET film is used. When the thickness is less than 100 μm, the above thickness is set because any material has low rigidity and is easily deformed during use.
The metal layer 112 is a metal having a uniform thickness without unevenness, and is made of aluminum, nickel, stainless steel, or the like having a thickness of 0.05 μm or more, which can maintain a specular gloss. In the present embodiment, aluminum laminated to a thickness of 0.06 μm by a vapor deposition method is used, and the surface thereof has a mirror-like gloss so as to reflect light well, and the light reflectance thereof is 60% or more.
In order to protect the metal layer from damage and rust, a metal protection layer 113 is formed on the metal layer 112. The metal protective layer 113 is made of a transparent resin such as an acrylic resin, an acrylic silicone resin, or a urethane resin, and in the present embodiment, an acrylic resin having a thickness of about 1 μm is used, and has a light transmittance of 95% or more so as not to inhibit light reflection in the metal layer 112.
The radius of the film 11 from the center of the bearing hole 12 is 5 to 100mm, the thickness is 0.1 to 1mm, and the radius of the bearing hole 12 is set to be in the range of 2 to 40mm (wherein, the radius is smaller than the radius of the film 11). The non-reflective portion 13 is tapered toward the center of the film 11, and has a shape such that its long side (line in the radial direction) passes through the center of the film 11 when extended toward the center of the film 11. And the length in the longitudinal direction (radial direction) is 0.3 to 4.0 mm. The width of the non-reflective portion 13 is set to an angle θ formed between the center of the thin film 11 and the two long sides of the non-reflective portion 1310.2 to 5 DEG, and the interval between the non-reflection parts 13 is set to be an angle theta formed by the long sides of the adjacent non-reflection parts 132Is 0.2 to 5 degrees. The portion between the non-reflective portions 13 is exposed from the metal protection layer 113 and is used as a reflective portion for reflecting incident light.
The non-reflective portion 13 is formed on the metal protective layer 113 by an offset method described later to have a thickness of 1 to 4 μm (i.e., a height difference between the non-reflective portion 13 and the reflective portion (metal protective layer 113) of 1 to 4 μm) with less influence of irregular reflection of incident light on measurement accuracy, and has a light reflectance of less than 10%. The non-reflective portion 13 is made of black ink I dedicated to offset printing. This is an ink specially prepared for gravure offset printing, and is characterized by a higher viscosity than inks used in other printing methods. The non-reflective portion 13 can be drawn thinner and with higher precision by being formed by an offset printing method using the offset printing ink than by being formed by another printing method. In the present embodiment, the dimensional accuracy of the non-reflective portion 13 other than the thickness thereof is a difference of ± 3 μm or less from the size of the recess of the depressed plate G described later.
Next, a method for manufacturing the reflection plate 1 for an optical encoder by an offset method will be described with reference to fig. 2.
First, a resin sheet to be a base material of the thin plate 11 is prepared (fig. 2 (a)). The resin sheet includes the resin layer 111 and the metal layer 112 as described above, the resin sheet is a PET film having a thickness of 188 μm, the metal layer 112 is an aluminum layer laminated to a thickness of 0.06 μm by an evaporation method, and the aluminum layer is in close contact with the PET film. The surface (the surface opposite to the resin layer) of the metal layer 112 has a specular gloss. Here, a commercially available resin sheet is used in consideration of production efficiency.
Next, an acrylic resin paint was applied to the glossy surface of the metal layer 112 to a thickness of about 1 μm, thereby forming a metal protection layer 113 (fig. 2 (b)).
Next, on the metal protective layer 113 of the resin sheet, black ink I dedicated to offset printing is printed in a radial line shape in a thickness of 1 to 4 μm in a predetermined pattern by a gravure offset method which is one of offset methods, to form the non-reflective portion 13 (fig. 2 (c)).
Here, a printing process by the gravure offset printing method in the embodiment of the present invention is briefly described. First, the black ink I put in the ink tray D is attached to the outer circumferential surface of the ink roller R partially immersed in the black ink I, and is taken out by rotating the ink roller R.
Next, while rotating the intaglio (gracure) G in the direction opposite to the ink roller R, the black ink I is transferred to the outer peripheral surface of the intaglio G engraved with the pattern corresponding to the non-reflection portion 13 and the alignment mark for the step of processing the bearing hole 12 and the outer shape, which will be described later. Further, since the final thickness of the non-reflective portion 13 can be controlled by adjusting the depth of the pattern of the depressed plate G, the degree of freedom of the thickness is improved compared with other printing methods, and therefore the non-reflective portion 13 can be formed thin. In the present embodiment, the depth of the pattern of the depressed plate is set to 10 μm.
Next, the excess black ink I is scraped off by the doctor blade S, and the black ink I is appropriately embedded in the concave portion of the depressed plate G.
Next, while rotating the blanket B in the direction opposite to the intaglio G, the black ink I is transferred to the outer peripheral surface of the offset plate O formed of a flat silicone rubber. At this time, the solvent or monomer contained in the black ink I dedicated to offset printing permeates into the blanket B, the cohesion of the black ink I is increased, and the pattern shape of the black ink I formed by the intaglio G is maintained. Here, the weight concentration of the offset printing ink is adjusted so that the solvent is appropriately condensed by absorption into the blanket B and volatilization from the surface, and the viscosity can be increased, and thus the shape retention property is good. Specifically, the viscosity is set higher than that of the ink for screen printing. Further, the ink exclusive for offset printing has almost no thixotropy indicating a change in viscosity with respect to shear rate, and is close to a newtonian fluid. On the other hand, the ink for screen printing generally has thixotropy. This is because, in screen printing, it is necessary that the screen printing ink smoothly fills the opening by generating a rolling phenomenon on the squeegee surface of the printing plate and that the screen printing ink generates a laminar flow in the opening at the time of plate separation to be appropriately transferred to the object to be printed, and on the other hand, it is not necessarily required to do so in offset printing.
In addition, when the depressed plate G is used, the shape accuracy of the black ink I transferred to the blanket B can be improved by forming the depressed portion with high accuracy.
Next, the black ink I is transferred onto the metal protection layer 113 of the resin sheet, and the non-reflection portion 13 is formed (fig. 2 (d)). At this time, the ink dedicated for offset printing is appropriately coagulated by absorption and volatilization of the solvent, and is transferred to the resin sheet while maintaining the shape. Further, since the ink used in the other printing method is not suitable as compared with an ink for offset printing in which solvent is absorbed and volatilized on the blanket B, the ink is inferior in shape retention property and cannot be appropriately transferred onto the resin sheet.
Next, the printed black ink I is dried and cured under predetermined conditions (temperature and time). Finally, the thickness of the non-reflective part 13 (i.e., the height difference between the non-reflective part 13 and the metal protective layer 113) is 1 to 4 μm.
Next, the bearing hole 12 is formed with the focal point portion of the radiation drawn by the non-reflective portion 13 (i.e., the portion that becomes the center of the circular plate body in the final form) as the center. The resin sheet is thermally cut by an ultraviolet laser to be processed. In this case, although the processing is performed based on the alignment mark, the alignment accuracy with the true center is 50 μm or less, and if it is larger than this, the position measurement accuracy of the object of the optical encoder is adversely affected.
Next, in the same manner as the processing of the bearing hole 13, the resin sheet is cut into a circular plate shape with a radius of a degree that at least the non-reflection portion 13 is entirely included, with the center of the bearing hole 13 as the center, with the alignment mark as a reference, to obtain the code wheel 1 for the optical encoder. Here, an ultraviolet laser is also used for processing (fig. 2 (e)).
According to the present invention, since the thin plate 11 is formed of a multilayer structure of a glossy metal and a resin, it has a light reflectance equal to or higher than that of a conventional structure made of only a metal, and the manufacturing cost can be kept low. Further, since the non-reflective portion 13 is the black ink I for offset printing formed by the offset method, the shape accuracy is equal to or higher than that in the case of manufacturing by the conventional electroforming method, the position measurement accuracy can be higher than that in the conventional case, and the manufacturing cost can be further reduced. Further, the metal protective layer 113 can prevent damage or deterioration of the metal layer 112 and ensure the adhesion of the black ink I. Further, since the height difference between the non-reflective portion 13 and the reflective portion is smaller than that in the conventional art, the irregular reflection of the incident light can be suppressed.
Further, since the multilayer structure of the glossy metal and the resin of the thin plate 11 is processed into a predetermined shape, the light reflectance is equal to or higher than that in the case of manufacturing by the conventional electroforming method, and the manufacturing cost can be suppressed to be low. Further, since the non-reflective portion 13 is formed by printing the black ink I dedicated for offset printing by the offset method, the shape accuracy is equal to or higher than that of the conventional electroforming method, the position measurement accuracy can be higher than that of the conventional method, and the manufacturing cost can be further reduced. Further, the non-reflective portion 13 can be formed with a smaller thickness and with improved shape accuracy and productivity as compared with the case where another printing method such as a screen printing method or the case where ink for another printing method is used.
While the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above embodiments, and may be related to other embodiments which can be regarded as similar to the above embodiments.
For example, in the above-described embodiment, the gravure offset method using the gravure G is adopted in the offset method, but is not limited thereto, and other methods such as flexographic, relief, lithographic and a combination with the offset method may be used.
The optical encoder reflecting plate 2 of fig. 3 has the same configuration as that described in the embodiment except that the entire shape is a strip-shaped and elongated thin plate 21, and the non-reflecting portion 22 is formed in close contact with the metal protective layer 213 perpendicularly to the longitudinal direction of the thin plate 21. In this embodiment, both ends of the thin plate in the longitudinal direction are connected in the shape of an annular rail, and thus the thin plate can be installed in a use space different from the disk body of the embodiment.
In the method of manufacturing the reflective plate 2 for an optical encoder according to this embodiment, when the non-reflective portion 22 is printed on the belt-shaped thin plate 21 by the offset printing method, printing is performed substantially in parallel according to a predetermined pattern, and in the step of forming the outer shape, the resin sheet is cut into a belt shape in a direction perpendicular to the non-reflective portion 22 with a width at least as wide as the non-reflective portion 22 is entirely included.
In addition, although the outer shape is processed by the ultraviolet laser, in the case of mass production, the manufacturing cost can be further reduced by using a dedicated processing jig such as a punch. In this case, the bearing hole 12 and the outer shape can be processed in the same step.
Further, as in the optical encoder reflective plate 3 of fig. 4, the black ink I dedicated to offset printing is printed on the metal protective layer 113 by an offset printing method in a layer shape in which radial openings are formed in a predetermined pattern, contrary to the embodiment, to form the non-reflective portion 31, and can be used as a reflective plate for an optical encoder. In this case, in the manufacturing method, the same as the embodiment is made except that its intaglio G (referred to as its printing plate in the case of using an offset method other than the intaglio offset method) is formed in a pattern reverse to the unevenness of the embodiment.
In the reflection plate 1 for an optical encoder according to the embodiment, the same effect can be obtained even when the non-reflection portion 13 is printed on the resin layer 111 side. In particular, when the metal protective layer 113 has irregularities or uneven thickness, there is a concern that dimensional accuracy of the non-reflection portion 31 is affected, and therefore, the metal protective layer can be formed with high accuracy by printing on the resin layer 111 side. The same applies to the optical encoder reflector 2 and the optical encoder reflector 3.
Claims (6)
1. A reflection plate for an optical encoder for measuring the position of an object,
the optical encoder reflector includes: a disc-shaped thin plate; a bearing hole formed in the center of the surface of the thin plate; and a plurality of narrow-stripe-shaped non-reflecting sections arranged in a radial pattern around the bearing hole,
the sheet has a multilayer structure in which a resin layer, a metal layer, and a metal protective layer are sequentially stacked,
the non-reflection part is formed on the metal protection layer in a clinging manner,
the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of a black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is within a range of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
2. A reflection plate for an optical encoder for measuring the position of an object,
the optical encoder reflecting plate comprises a rectangular thin plate and a plurality of narrow strip-shaped non-reflecting portions arranged in a predetermined pattern in the surface of the thin plate,
the sheet has a multilayer structure in which a resin layer, a metal layer, and a metal protective layer are sequentially stacked,
the non-reflection portion is formed on the metal protection layer in close contact with the thin plate in a direction substantially perpendicular to the longitudinal direction of the thin plate,
the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of a black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is within a range of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
3. A reflection plate for an optical encoder for measuring the position of an object,
the optical encoder reflector includes: a disc-shaped thin plate; a bearing hole formed in the center in the plane of the thin plate; and a non-reflection portion having a plurality of narrow-stripe-shaped openings arranged in a radial line in a predetermined pattern with the bearing hole as a center;
the sheet has a multilayer structure in which a resin layer, a metal layer, and a metal protective layer are sequentially stacked,
the non-reflection part is formed on the metal protection layer in a clinging manner,
the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of a black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is within a range of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
4. A method for manufacturing a reflection plate for an optical encoder for measuring the position of an object, comprising the steps of:
coating a metal protective layer with a uniform thickness on the glossy surface of a metal layer of a resin sheet comprising the resin layer having the metal layer with the glossy surface formed with the uniform thickness in the surface to form a multilayer film;
forming a non-reflective portion on the metal protective layer of the resin sheet by radially printing a black ink dedicated for gravure offset printing in a predetermined pattern by a gravure offset method;
drying and curing the black ink under a predetermined condition;
forming a bearing hole with a focal point portion of the radiation depicted by the non-reflection portion as a center; and
cutting the resin sheet into a disc shape with a predetermined radius around the center of the bearing hole,
the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of a black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is within a range of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
5. A method for manufacturing a reflection plate for an optical encoder for measuring the position of an object, comprising the steps of:
forming a resin layer, and coating a metal protective layer with a uniform thickness on the glossy surface of a metal layer of a resin sheet comprising the resin layer on which the metal layer having the glossy surface is formed with a uniform thickness in a surface of the resin layer to form a multilayer film;
printing, by a gravure offset method, a black ink dedicated to gravure offset printing in a layer shape in which openings in a radial line shape are formed in a predetermined pattern on the metal protective layer of the resin sheet, thereby forming a non-reflective portion;
drying and curing the black ink under a predetermined condition;
forming a bearing hole with a focal portion of the radiation depicted by the opening as a center; and
cutting the resin sheet into a disc shape with a predetermined radius around the center of the bearing hole,
the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of a black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is within a range of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
6. A method for manufacturing a reflection plate for an optical encoder for measuring the position of an object, comprising the steps of:
coating a metal protective layer with a uniform thickness on the glossy surface of a metal layer of a resin sheet comprising the resin layer having the metal layer with the glossy surface formed with the uniform thickness in the surface to form a multilayer film;
printing black ink dedicated to gravure offset printing substantially in parallel in a predetermined pattern on the metal protective layer of the resin sheet by an offset method to form a non-reflective portion;
drying and curing the black ink under a predetermined condition; and
cutting the resin sheet into a rectangular shape with a predetermined width such that the long side of the resin sheet faces in a direction substantially perpendicular to the non-reflective portion,
the metal protective layer is formed of a transparent resin having a light transmittance of 95% or more, the metal layer is formed of a glossy metal having a light reflectance of 60% or more, the non-reflective portion is formed of a black ink dedicated for gravure offset printing, the dimensional accuracy of the length and width of the non-reflective portion in the longitudinal direction is within a range of ± 3 μm or less with respect to the size of the recessed portion of the gravure plate, the light reflectance of the non-reflective portion is less than 10%, and the thickness of the non-reflective portion is 1 to 4 μm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911388728.5A CN113124750A (en) | 2019-12-30 | 2019-12-30 | Reflection plate for optical encoder and method for manufacturing same |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911388728.5A CN113124750A (en) | 2019-12-30 | 2019-12-30 | Reflection plate for optical encoder and method for manufacturing same |
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| CN113124750A true CN113124750A (en) | 2021-07-16 |
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