JPS625126A - Disk for rotary encoder and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a substantially linear slit pattern and to eliminate a warp of a disk, by forming slits of an optical rotary encoder by plating so that a slit has a section wherein the lower end of an umbrella is larger than the maximum width of a handle. CONSTITUTION:A resist pattern 2 corresponding to slits 4 of a disk 11 is printed on an Al thin plate 1, Ni-P 3 is formed by electrolytic plating so that the width of the lower end of an umbrella 3A is prepared to be larger than the maximum width of a handle 3B, and thereby a linear pattern 800 can be obtained. The Al plate 1 is removed by etching with dilute hydrochloric acid, and than the resist 2 is removed. Next, the disk 11 is pressed with a heat by jigs 5 and 6, so that the warp thereof be corrected. Since the meandering edge 700 of the resist pattern is wholly contained in the pattern 800 according to this constitution, a linear slit pattern is obtained, and thus a disk for a rotary encoder having little warp age and high reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary encoder disk and a method for manufacturing the same.

[Prior Art] Rotary encoders are used in a wide range of fields as sensors that detect rotation angles.

A rotary encoder, for example, an optical rotary encoder, includes a rotating disk with many slits on its side. Among these, disks for high-resolution encoders are manufactured by depositing metal on a glass plate and etching the deposited metal to form slits, etc., but the manufacturing process is complicated and the product is It is expensive and the encoder is not easy to assemble because it is made of a glass plate.

On the other hand, cheaper encoders are manufactured by mechanically punching a metal plate or by forming a resist on the metal plate and photo-etching it, but the resolution of the encoder is inevitably low. For example, when forming slits on a metal plate by etching, so-called side etching becomes a problem, making it difficult to narrow the slit spacing, and the slit width also varies widely, causing protrusions on the slit. This also tends to occur, making it difficult to arrange slits with high density.

Furthermore, it is also known to obtain a metal disk by forming slits by pattern plating. The slits of the disks made by this method have no bulk part at all, and in this manufacturing method, the slits in the disks made by this method are
), a resist pattern 200 is formed on a thin metal plate 100, plating is performed according to the pattern 200, a metal layer 300 having an encoder disk pattern is formed on the thin metal plate 100, and then a resist pattern 200 is formed on the thin metal plate 100.
and remove the resist layer 200.

This disk was made using a method suitable for increasing the density of the slit arrangement, but when forming the resist pattern 200 for plating, the edge portions of the pattern were removed as shown in FIGS. Or, as shown in (C), various end face shapes 201, 202, or 203 are exhibited, which is far from the ideal end face shape 400 shown by the dotted line.

If the edge portion of the resist pattern digs into the inside of the pattern as shown in the end shape 201 or protrudes outside the pattern as shown in the end shape 202, the slit pattern of the metal layer 300 formed by plating becomes uniform. As a result, as shown in FIG. 4, for example, a meandering pattern 700 deviated from the ideal linear pattern 600 was obtained, which was not desirable as a slit pattern for an encoder.

In particular, as the area of the slit pattern becomes larger or the slit density increases, such non-uniformity becomes more noticeable, and there is a drawback that uniform patterning cannot be achieved over the entire surface.

It is difficult to keep the internal stress generated during plating work to a minimum, and if internal stress occurs during plating work, the disc will warp, but this warp will occur between the slit part of the disc and the fixed slit plate or This changes the distance between the light-receiving element and the signal strength and contrast, which can cause malfunctions. Therefore, it is necessary to reduce this warpage as much as possible in order to make the slit pattern uniform.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to solve the above-mentioned drawbacks and to form a nearly linear slit pattern when manufacturing a disk for an optical rotary encoder using a pattern plating method. An object of the present invention is to provide a disc for a rotary encoder and a method for manufacturing the same.

Another object of the present invention is to manufacture a rotary encoder disk by pattern plating.
It is an object of the present invention to provide a method for manufacturing a disk for a rotary encoder, which can solve the above-mentioned drawbacks, form a nearly straight slit pattern, and eliminate the above-mentioned warpage.

[Means for Solving the Problems] In order to achieve the above object, the rotary encoder disk of the present invention is a rotary encoder disk provided with slits, in which the slits are formed by plating, and the cross-sectional shape of the slits is It consists of an umbrella part and a root part, and is characterized in that the width between both edges of the umbrella part, that is, the width of the lower end of the umbrella, is set larger than the maximum width of the root part.

The manufacturing method of the present invention includes a step of attaching a resist to a portion other than the disk pattern on a thin metal plate, and a step of attaching a metal layer thicker than the resist onto the thin metal plate by plating to form a disk with a disk pattern. The method is characterized by comprising steps of removing the thin metal plate and peeling off the resist.

Another aspect of the manufacturing method of the present invention includes the step of attaching a resist to a portion other than the disk pattern on a thin metal plate, and the step of attaching a metal layer thicker than the resist onto the thin metal plate by plating to produce a disk with a disk pattern. It is characterized by comprising a step of forming, a step of removing the thin metal plate and a resist, and a step of sandwiching the obtained disk between jigs and subjecting it to heating and pressure treatment.

[Example] The present invention will be described in detail below with reference to the drawings.

Sequential steps in an embodiment of the manufacturing method of the present invention are shown in FIGS. 1(A) to 1(F).

In FIG. 1(A), reference numeral 1 indicates a cross section of a thin metal plate serving as a cathode. When the thin metal plate 1 is removed by etching in the subsequent step shown in FIG. In this case, when the thin metal plate 1 is etched away, the electrolytically plated metal is not etched, and only the thin metal plate 1 can be etched and removed with high precision. The suitable material for the thin metal plate l is as follows.

These include aluminum, tin, and zinc.

FIG. 1(B) shows the resist forming process, and here the first
A resist pattern formed in a pattern corresponding to the slit portion 4 of the disk shown in FIG. Although screen printing or gravure printing may be used to form the resist pattern 2 in areas other than the slit portion 4, it is preferable to use a photoresist that can easily form a fine pattern.Resist pattern 2 made of photoresist In the formation method, the resist pattern 2 can be obtained through photoresist coating, exposure, and development processes. As a photoresist,
Eastman Kodak's KPR, KOR, KPL,
KTFR, KMER, Tokyo Ohkasha TPR, 0MR8
1. Negative types such as Fuji Pharmaceutical's FOR, Eastman Kodak's KADR, and Sibley's AZ-13
A positive type such as No. 50 can be used. Alternatively, a dry film resist can also be used, but a liquid resist is superior in terms of resolution.

FIG. 1(C) shows the electrolytic plating process, and 3 indicates the metal deposited thicker than the layer thickness of the resist pattern 2.
The metal to be electrolytically plated may be any metal that can be plated, but from the viewpoint of hardness, rigidity, corrosion resistance, economy, and heat treatment characteristics, nickel or nickel alloys are preferred, especially N1-P and the like. A hard metal with a low melting point is suitable because stress can be sufficiently removed by simply heating it at a low temperature after forming the slit. The plating method allows for a high-density slit arrangement, with 3 slits/mra
Furthermore, it is particularly suitable for manufacturing disks with a slit density of 5 slits/am or more.

FIG. 1(D) shows the process of removing the thin metal plate 1.

The thin metal plate 1 is removed by etching or mechanically peeling off, but in order to avoid damage to the disk and make the process more reliable, etching is preferred. By performing partial etching, it is also possible to leave a part of the thin plate on the disk side as a reinforcing plate. As the etching solution, when aluminum, tin or zinc is used as the metal plate 1, as described above, an acidic aqueous solution such as dilute hydrochloric acid, or an alkaline aqueous solution such as a sodium hydroxide solution can be used. Note that when etching removal is performed, the resist pattern 2 remains on the disk side as shown in FIG. 1(D), but when peeling and removal is performed, most of the resist pattern 2 remains on the thin metal plate side.

FIG. 1(E) is a cross-sectional view showing the resist pattern peeling process, and represents the end surface when the slit portion 4 of the disk 11 is cut at the dotted line y-'y as shown in FIG. ing. To remove the resist pattern 2, a commercially available resist remover may be used, such as Nagase Sangyo's resist strip rJ-100J, rN-500J.
etc. can be used. Even when the thin metal plate 1 is peeled off in the process shown in FIG. 1(D), partial residues of the resist remain on the disk.
It is preferable to perform the resist stripping shown in FIG.

The disk formed through the above steps may be warped due to internal stress during plating. The degree of warpage varies depending on the type of plating and operating conditions, but is usually at least 100IL11 or more. In addition,
Warpage here refers to the warpage of the disk itself, that is, the distance between the two planes when the flat part of the disk is sandwiched between two mutually parallel geometric planes, and the distance between the two planes is the minimum. refers to the value obtained by subtracting the thickness of the disk from
In the following, unless otherwise specified, warpage refers to such a value.

Therefore, in the present invention, the obtained metal disk is further sandwiched between jigs and subjected to heat and pressure treatment, thereby correcting such warpage. FIG. 1(F) shows a process of correcting the warp by sandwiching the warped metal disk 11 between the jigs 5 and B and then applying heat and pressure treatment.

In this case, the heating temperature is 0.3 to 0.8 times, preferably 0.35 to 0.7 times, more preferably 0.37 to 0.0 times the melting point or eutectic temperature of the metal expressed in absolute temperature. .8 times is suitable. If the heating temperature is lower than the appropriate temperature range, the warpage is often not corrected, and if it is higher, the fine shape of the slit portion 4 of the disk 11 may be deformed.
Furthermore, in the case of heating in air, which often causes deterioration of the disk 11, oxidation of the metal is unnecessarily promoted.

The heating time is preferably 1 minute to 3 hours, particularly 5 minutes to 1 hour from the viewpoint of reliability and workability.

Of the jigs 5 and 8 that sandwich the disk 11, the disk 1
At least one of the surfaces in contact with the disk must be a rigid body with good flatness, but the other surface may be made of a flexible material such as fluororesin. 1. A jig having a degree of flatness that can be used in the present invention, although it is necessary that the flatness is equal to or higher than the degree of flatness.
For example, one with a warpage of about 10 gm is relatively easily available. As a heating method, a heater may be attached to the jig itself, or a disk may be sandwiched between the jig.
The rigid material of the jig, which can be heated in an oven, electric furnace, etc., must not melt or soften at the temperature at which it will be used, and in order to suppress the deformation of the jig due to heating, It is better to have a small coefficient of thermal expansion, especially 50
When used at high temperatures of 0°C or higher, the coefficient of linear expansion is l
Ceramics, porcelain, quartz glass, etc. can be cited as examples of materials having a preferable value of 0XIO" or less. At low temperatures, metals, sorter glass, etc. can also be used.

Pressure is applied at the same time as heating, the pressure is 0.5 g weight/
The pressure may be in the range of am2 to 100 kg force/c II2, but in order to avoid deformation of the slit portion of the disk, the pressure is preferably such that the warp of the disk is corrected, and the pressure is 1 g force/cm2 to
500g weight/c112 is suitable.

According to the present invention, as shown in FIG. 1(c), plating is performed so that the deposited metal 3 is thicker than the layer thickness of the resist pattern 2, so that the cross-sectional shape of the plated metal 3 is shaped like an umbrella. 3A and a root portion 3B, and the width between both edges of the umbrella portion 3A, that is, the width at the lower end of the umbrella portion 3A, is set to be larger than the maximum width of the root portion 3B. Therefore, since the width between both edges of the bulk portion 3A formed on the surface of the metal 3 is formed into a straight line pattern 800 (FIG. 4) that includes all of the meandering pattern 700 described above with reference to FIG. The slit pattern becomes linear and is extremely effective in forming the slit pattern of the encoder.

The reason why the periphery of the umbrella portion 3A is straight is that the plating grows more uniformly than the base. The width of the lower end of the umbrella portion 3A is constant everywhere, and
The thickness of the cap is also approximately the same as the width of the bottom edge.

In order to further clarify aspects of the present invention, examples will be given and explained below, but the present invention can of course be applied to the manufacture of movable slit plates for beam near gauges, fixed slit plates for encoders, etc. Therefore, the present invention is not limited to the following embodiments, and various modifications are possible.

Example 1 Negative-type resist microresist-747 manufactured by Eastman Kodak Co. was applied on a thin aluminum plate with a thickness of 80 mm.
-110cSt J was coated to a film thickness of 37zm, prebaked, exposed to a high pressure mercury lamp through an encoder disk pattern, developed using a special developer and rinse solution, and postbaked. A resist was formed on the area other than the disk pattern on one side of the thin plate.

Next, using the nickel-phosphorus electrolytic plating solution "Nickelin B" manufactured by Jitsukei Pharmaceutical Industries Co., Ltd., a thin aluminum plate was used as a cathode to electrolytically plate a nickel-phosphorus alloy with a thickness of 35IL, which is thicker than the thickness of the resist layer, on the patterned area of the surface. It was formed by After removing the thin aluminum plate by etching with 18% by weight hydrochloric acid, the resist was removed using a resist strip rN-500J manufactured by Nagase Sangyo Co., Ltd.

The obtained nickel-phosphorus alloy disk had an outer diameter of 24 layers, a thickness of 35 IL, and 400 slits. A total of 100 disks were made in the same manner and the warpage was measured, and the warpage was tsoILm~2m.
m was in the range of 0.Next, these disks were sandwiched in order between commercially available plate glasses, a pressure of 38 g weight/C112 was applied, and heating was performed at 250° C. for 35 minutes, followed by natural air cooling. As a result, the warpage of each disk was 3
100 metal disks for an optical rotary encoder with excellent flatness were obtained with a value of 0 or more, which decreased to a value in the range of ~20 IL■.

Example 2 After forming a resist pattern on a thin aluminum plate in the same manner as in Example 1, electrolytic plating was performed in a Watt-type nickel bath containing Acuna SXJ manufactured by Jitsukei Pharmaceutical Industries Co., Ltd. After forming a nickel layer with a thickness of 25 ILm, the thin aluminum plate was removed by etching with a 5 weight percent sodium hydroxide aqueous solution, and then resist strip rN-50 from Nagase Sangyo Co., Ltd.
04 and resist strip rN-500J was used to remove the resist. The resulting disc has a thickness of 25
The length was 4 m, the outer diameter was 22 mm, and the number of slits was 7H. A total of 100 disks of the same size were made using the same procedure and the warpage was measured, and the warp was 150.
These disks were sandwiched between ceramic plates with polished surfaces, and 3 g
Heating was performed at 370° C. for 45 minutes under a pressure of 1.5 m/m 2 , followed by natural air cooling. As a result, the warpage of each disk was reduced to a value in the range of 3 to 20 layers.
As a result, 100 metal disks for optical rotary encoders with excellent flatness were obtained.

Example 3 The electrolytic plating process was carried out in the same manner as in Example 2. Next, the resist was removed using Nagase Sangyo Co., Ltd.'s resist strip rN-500J, and then the aluminum thin plate was removed by etching with a 5% by weight sodium hydroxide solution. do,
Through this process, 100 discs with a thickness of 25IL, an external diameter of 22mm, and a number of slits of 768 were obtained. All of these warps had values in the range of 150 to 500 JLta.Next, when these disks were subjected to the same heat and pressure treatment as in Example 2, the warp of each disk was 3 to 500 JLta.
100 metal disks for an optical rotary encoder with excellent flatness were obtained with a value of 0 or more, which decreased to a value in the range of 20 uLm.

[Effects of the Invention] According to the rotary encoder disk of the present invention, the size of the bulk can be controlled in any way, and by controlling the size of the root and the growth time of the plating, any desired thickness and slit width can be obtained. is obtained. Therefore, in some cases, it is possible to construct a disc having a bulbous portion with a width much higher in magnification than the width of the root.

Moreover, according to the manufacturing method of the present invention, it is possible to form a nearly linear slit pattern, and moreover, it is possible to form a highly accurate and reliable slit pattern using inexpensive metal as a material and having a high density array of slits with excellent flatness. It is possible to manufacture discs for rotary encoders.

[Brief explanation of drawings]

FIGS. 1(A) to (F) are schematic diagrams showing one embodiment of the sequential steps of the method for manufacturing a metal disk according to the present invention. FIG. 2 is a plan view showing an example of a metal disk incorporated into an optical rotary encoder. 3A, 3B, and 3C are cross-sectional views for explaining conventional pattern plating. FIG. 4 is an explanatory diagram of the slit pattern. 1... Metal thin plate, 2... Resist pattern, 3... Electrodeposited metal, 3A... Umbrella part. 3B... Root portion, 4... Slit portion, ψ 5... Jig, 11... Metal disk, 100... Metal thin film. 200... Resist pattern, 201.202... End face shape, 300... Plated metal layer, 400... Ideal pattern, 800... Linear pattern, 700... Meandering pattern, 800... - Pattern according to the invention. Plan of Tensufu Figure 2 Explanatory diagram of Suso and Sotonozu Tarn Figure 4

Claims (1)

[Claims] 1) In a rotary encoder disk provided with a slit, the slit is formed by plating, and the cross-sectional shape of the slit is composed of an umbrella portion and a root portion, and is wider than the maximum width of the root portion. A disc for a rotary encoder, characterized in that the width between both edges of the umbrella portion is set large. 2) a step of attaching a resist to a portion other than the disk pattern on the thin metal plate; a step of attaching a metal layer thicker than the resist onto the thin metal plate by plating to form a disk having the disk pattern; A method for manufacturing a rotary encoder disk, comprising the steps of removing the thin metal plate and removing the resist. 3) a step of attaching a resist to a portion other than the disk pattern on the thin metal plate; a step of attaching a metal layer thicker than the resist onto the thin metal plate by plating to form a disk having the disk pattern; A method for manufacturing a disc for a rotary encoder, comprising: removing the thin metal plate and removing the resist; and sandwiching the obtained disc between jigs and subjecting it to heating and pressure treatment.