JPH08229955A - Master mold for molding optical scale, production thereof, production of stamper for molding optical scale and production of optical scale - Google Patents

Abstract

PURPOSE: To accurately produce a master mold for molding an optical scale within a short time by providing a soft layer having hardness lower than that of a master on the master having a smooth surface and cutting the soft layer to form a scale pattern. CONSTITUTION: A soft layer 1 having hardness lower than that of a master 2 is provided on the master 2 having a smooth surface and subsequently baked in an oven and, thereafter, the soft layer is laminated. Next, the soft layer 1 is cut so as to form a scale pattern. Since the hardness of the soft layer 1 is different from that of the master 2, only the soft layer 1 can be selectively cut by inclining a bite. The depth of the scale pattern can be also controlled only by controlling the feed quantity of the bite. By this constitution, a master mold 4 for molding an optical scale is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master die used for molding, and more particularly to a master die for producing an optical scale, a stamper for producing an optical scale, and a method for producing an optical scale, which are suitable for optical encoders and the like.

[0002]

2. Description of the Related Art Conventionally, in information devices such as printers, optical encoders have often been used to detect the position and speed of movable parts such as carriages. Such an optical encoder is usually fixed to a movable part, projects light on an optical scale on which an optical code is recorded, and photoelectrically converts the modulated light to encode position information of the movable part. It was configured to be taken out as a received electric signal. The optical scale includes (1) a metal plate provided with slits by etching, (2) silver, copper, etc. on a transparent substrate such as glass or plastic.
A metal such as chromium or aluminum is vapor-deposited, and only the metal layer is removed by etching into a slit shape. (3) A slit pattern is drawn on the mask blanks using a resist, and the photomask removed by etching into a slit shape is used as a master mold. A silver salt film exposed to light and patterned by a development process has been used. However, in (1), the slit width that can be etched is limited to more than twice the metal thickness, and it is difficult to record a fine code. Further, the other ones have a drawback that the cost is high because the photosensitive resin which is complicated in the manufacturing process and expensive for etching is used.

Further, the method using a silver salt film has a limit in cost reduction because the price of the silver salt film is high.

Therefore, Igaki et al. Disclose that an inexpensive optical scale can be provided by injection molding or compression molding by using a scale having the shape disclosed in Japanese Patent Laid-Open No. 62-3616. When the printer is equipped with the optical encoder of the above shape for detecting the position and speed of the movable part such as the carriage, the scale length is required to be 210 mm or more for A4 portrait. The width is usually about 3 to 15 mm. When molding such an elongated scale by the injection method, it is necessary to make the thickness thick and the productivity is not good because it is a single-wafer processing. On the other hand, in the compression method, a large number of patterns can be arranged on one die, but since the transfer time is long and the single-wafer processing is used, this is also low in productivity.

As described above, the conventionally used optical scale cannot be mounted on a low-priced general-purpose printer or the like because of high manufacturing cost regardless of which manufacturing method is used.

Therefore, as a result of studying a method for producing an optical scale which has high productivity and low cost, the extrusion molding method of the present invention has been reached.

That is, a light-transmitting member is provided with a marking portion, and the marking portion has a light-transmitting portion, and an optical non-lighting surface composed of an inclined surface whose incident angle with respect to an incident light ray is set to a critical angle or more. In a method of manufacturing an optical scale in which transmissive portions are alternately formed, 1. 1. The first step of making a roll stamper by mounting a mold larger than the corresponding pattern of the desired optical scale on the roll. Second step of melting a thermoplastic resin having a light transmittance of 50% or more at a wavelength to be used with an extruder and extruding it from a T-die. The molten resin is sandwiched between the roll stamper and the mirror surface roll to form a sheet, and at the same time, the pattern of the scale is transferred.
It was found that by using the method for producing an optical scale characterized by producing the sheet-like optical scale, it is possible to dramatically reduce the cost, which was impossible in the past.

For example, when a thin plate-shaped molded article is produced, the conventional compression method has a cycle of heating and cooling, and the molding tact time per time is about 3 minutes at the minimum, so that even a single mold is required. Even if 60 scale patterns are provided, the production amount per minute is only 20. On the other hand, in the rotary molding method (hereinafter referred to as RM method) of the present invention, the size of one molded product is 1
When a molding machine with a roll diameter of 0 × 450 mm and a roll diameter of 300 mmφ is used, even if 15 scale patterns are provided on one mold, two rolls can be mounted on one roll mold and the molding speed is Since it can be molded at a high speed of 1 to 7 m / min, the production amount per minute is 30 to 210 and the productivity is 1.5 to 7.5 times that of the compression method. Further, if the number of molds taken per sheet is increased, the difference in productivity becomes very large. Further, the RM method has an advantage that the durability of the mold is good because the molding is performed in a state where the resin is molten and the molding pressure is smaller than that of the compression method. When the optical scale is produced by this method, it is possible to provide a very low-cost product for the above reason.

[0009]

In order to produce an optical scale by this method, it is important to produce a long stamper accurately, stably and at low cost. Further, for that purpose, it is necessary to accurately and surely create a master mold for manufacturing the stamper. However, conventionally, a phosphor bronze plate with few impurities was created, and it was cut with an ultra-precision processing machine to create a scale pattern, which was used as a master mold. For example, when trying to make a precise and long scale pattern with a pitch of 100 μm or less, since the above master type material is relatively hard, it must be cut little by little using a diamond cutting tool. Therefore, there is a problem that the processing time becomes very long, and there is a high risk of failure in master mold production due to an accident such as power failure or earthquake during processing.

In addition, the price of the thick and large phosphor bronze plate, which is a master type material and has few impurities and is rigid, is also high, which causes a cost increase in stamper production.

On the other hand, in order to manufacture a stamper from a master mold, conventionally, a UV curable resin (2P) is applied to the master mold, a glass plate is placed on the master mold and ultraviolet rays are applied to cure the 2P. After that, the replica surface was subjected to a conductive treatment, further electroformed, and then the back surface was polished, trimmed to fit the outer dimensions, and a fixture was welded, which was a complicated process.

On the other hand, when forming a stamper having a large area, for example, when manufacturing a stamper having a size of 200 × 500 mm, it is necessary to rotate the replica master to form a film in order to make the film thickness uniform. At least the inner diameter of the sputtering apparatus is 540 mmφ or more. Making larger ones requires larger and larger equipment, which is not practical. Further, in the case of making a long and narrow stamper as in the above example, there is a problem that the stress of the sputtered film is likely to have a large difference depending on the location, and film cracking is likely to occur in the electroforming process.

Simplification of this series of steps has been required in order to reliably and inexpensively supply the stamper, and thus to provide a more inexpensive and highly accurate optical scale.

The first to eighth inventions according to the present invention (claims 1 to 1)
The invention of No. 8) is to provide a method for producing a master mold for optical scale molding with high accuracy in a short time.

An object of the ninth invention (the invention of claim 9) according to the present invention is to provide a master mold for optical scale molding which is highly accurate and inexpensive.

The tenth, eleventh and twelfth aspects of the present invention
The object of the invention of (claims 10, 11 and 12) is
An object of the present invention is to provide a method for manufacturing an optical scale molding stamper inexpensively and accurately.

An object of a thirteenth invention (the invention of claim 13) according to the present invention is to provide a method for manufacturing an optical scale in a short time and with high accuracy.

[0018]

The above object can be achieved by the following means.

That is, according to the present invention, a master for optical scale molding is characterized in that a soft layer having a hardness lower than that of the master is provided on a master having a smooth surface, and the soft layer is cut to form a scale pattern. A mold manufacturing method is proposed, the master is a glass or ceramic plate, the master is a metal or alloy plate, the soft layer is a resin, and the soft layer is a soft metal or soft alloy. Moreover, the difference in hardness between the master and the soft layer is 5 in Vickers hardness.
It includes 0 or more, that a metal or alloy having a smaller ionization tendency than the metal used in electroforming or a conductive substance is used in both the master and the soft layer, and that the metal used in electroforming is nickel.

The present invention also proposes a master mold for optical scale molding, which is characterized by having a pattern of a soft layer having a hardness lower than that of the master on a smooth master.

The present invention further has a conductive soft layer having a smooth surface and having an ionization tendency smaller than that of the metal used for electroforming, and a conductive soft layer having a smaller ionization tendency than that of the metal used for electroforming. After cutting the layer to form a scale pattern to obtain a master mold for optical scale molding,
The stamper is produced by directly subjecting the formed pattern surface to electroforming of a metal, wherein the metal used for electroforming is nickel. Further, the present invention provides a transfer master having an uneven scale pattern formed by an ultraviolet curable resin, which is obtained by laminating an ultraviolet curable resin layer on the pattern surface of the master mold for optical scale molding and curing the resin layer by irradiating with ultraviolet rays. Then, the stamper is produced by subjecting the scale pattern surface of the transfer master to electrocasting having a hardness higher than that of the transfer master, and is a method for manufacturing an optical scale stamper.

Further, according to the present invention, a roll type having a scale pattern on its peripheral surface and a roll arranged opposite to the roll type are heated to a predetermined temperature by means of pushing out a thermoplastic resin while rotating each at a desired speed. Continuation of an optical scale having a step of supplying a thermoplastic resin between the roll mold and the roll, and a step of transferring the scale pattern by pressing the thermoplastic resin between the roll mold and the roll The manufacturing method is a continuous manufacturing method of an optical scale, characterized in that a roll mold manufactured by using the stamper is used for molding.

[0023]

According to the conventional method for producing the master mold for the optical scale by cutting the metal plate, the machining requires a very long time. However, according to the present invention, when the master die for the optical scale is manufactured, To manufacture a master mold for an optical scale accurately and at low cost by providing a soft layer having a hardness lower than that of the master on a master having a smooth surface and cutting the soft layer to form a scale pattern. You can

Further, of the above master molds, a master mold and a soft layer having conductivity are used, and the master mold is directly or after being subjected to a mold release treatment, the steps of electroforming-back surface polishing-peeling-trimming-fixing tool welding. The stamper can be manufactured accurately and at low cost by the manufacturing method having That is, the stamper manufactured by the above-described manufacturing method has better conductivity on the surface of the master die than the conventional sputtered film, so that the film thickness distribution during electroforming is narrow, the time required for the polishing step is short, and the cost is low. Further, since the amount of polishing is small, the residual stress due to polishing is also small and the durability is good. Further, by using an inexpensive and durable stamper manufactured by the above manufacturing method, by molding an optical scale by an extrusion molding method, it is possible to provide an optical scale that is more inexpensive and highly accurate than conventional ones. Become.

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

FIG. 1 is a schematic view showing an example of a method for manufacturing a master mold according to the present invention.

In order to manufacture the master mold for optical scale molding of the present invention, as shown in FIG. 1A, a soft layer 1 having a hardness lower than that of the master 2 is provided on the master 2 having a smooth surface.

Materials for the master 2 used in the present invention include metals and alloys such as steel, chrome steel, aluminum alloys, die steel (maraging steel) and stainless steel, or glass, alumina, zirconia and the like. Ceramics of can be used. The surface of the master 2 is preferably smoothed by polishing or the like, and has a flatness of 1
It is preferably 100 μm or less, more preferably 30 μm or less in a 00 mm square. It is better that the thickness is also uniform, and if the thickness of the master is 10 mm, then 0.5 m per 100 mm square
m or less is preferable.

Examples of the material of the soft layer 1 include resins such as acrylic resin, styrene resin, polycarbonate resin, polyolefin resin, polyamide resin, polyimide resin, silicone resin, polyester resin, polysulfone resin, lead, zinc, gold and silver. , Platinum, tin, magnesium, pure iron, pure copper, aluminum, indium and other soft metals and solder, phosphor bronze, brass, free-cutting brass, alloys such as 22 gold, and other fine particles such as aluminum and carbon black were hardened with resin. Examples thereof include waxes having a melting point of 100 ° C. or higher.

When the soft layer 1 is provided on the master 2, the surface of the master 2 may be polished and the surface may be coated with a surface treatment agent in order to enhance the adhesion between the master 2 and the soft layer 1.
Examples of such surface treatment agents include silane coupling agents and the like.

Then, in an oven or the like at 25 ° C to 200 ° C for 3
After baking for 0 to 3 hours, the soft layer is added to 20 to 30.
Laminate with a thickness of 0 μm.

The difference in hardness between the master 2 and the soft layer 1 is preferably 50 or more in Vickers hardness.

Next, the soft layer 1 is cut so as to form a scale pattern as shown in FIG. 1-b.

To cut the soft layer 1, diamond,
A tool made of ultra-high hardness steel, cemented carbide, tool steel, alumina ceramics, BN, Co-Cr-W-Mo alloy, or the like is used. The hardness of the cutting tool is preferably Vickers hardness of 50 or more, preferably 100 or more than that of the soft layer 1.

Since the hardness of the soft layer 1 and that of the master 2 are different, it is possible to selectively cut only the soft layer 1 by tilting the cutting tool, and to scale easily by controlling the feed amount of the cutting tool. You can also control the depth of the pattern.

Thus, the master mold 4 for optical scale molding is obtained as shown in FIG. 1-c.

FIG. 2 is a schematic view of a part of the process of forming a stamper using the conductive master mold of the present invention. The above-mentioned master mold manufacturing method can be preferably used for preparing the conductive master mold. In this case, the material of the soft layer 1 and the master 2 is preferably a metal, an alloy, or a conductive substance whose ionization tendency is smaller than that of the metal used for electroforming described later. It is particularly preferable to use a material having a smaller ionization tendency than nickel as the material of the soft layer and the master. Examples of the conductive substance include metals, alloys, carbon and conductive polymers. As a metal having an ionization tendency smaller than nickel, nickel, tin, copper, silver,
Examples include platinum and palladium. To make a stamper using a conductive master mold, use a metal or alloy or conductive material having a smaller ionization tendency than the metal used for electroforming in both the master and the soft layer, as shown in FIGS. 1-a to 1-c. The master mold 4 is obtained by the same method (FIG. 2-a).

Next, the master mold is attached to an electroforming holder to form an electroforming layer 5 having a thickness of 50 to 500 μm (FIG. 2).
-B).

Nickel is particularly preferable for the electroformed layer 5.

Then, the back surface is polished to obtain a laminate having no unevenness and good flatness (FIG. 2-c).

Next, the electroformed layer 5 is peeled off from the laminate in a clean room to obtain a stamper made of the electroformed layer 5.

If the adhesion between the master die 4 and the electroformed layer 5 is too good, the master die 4 will be damaged when the electroformed layer 5 is peeled off. Therefore, the surface of the master die 4 is subjected to a known release treatment such as oxidation treatment or nitriding treatment. It is preferable to reduce the adhesion between the two by treatment.

In the stamper manufacturing method of the present invention, since the master mold is made of a conductive substance, the conductive treatment which has been conventionally required is not required, and the process is simplified. Conventionally, defects such as film cracks and wrinkles caused by pinholes and stresses generated by forming a conductive film by sputtering can be reduced.

The stamper thus obtained is provided with fixing tools 8 and 9 at both ends of the stamper 7, as shown in FIG.
It is attached to the stamper roll as shown in.

In the example of FIG. 2, the manufacturing method of the stamper using the conductive master mold has been described, but the stamper similar to the above can be obtained by the following method without using the conductive master mold. In this case, a known release agent is applied to the surface of the master die 4 obtained by the steps of FIGS. 1-a to 1-c, and then an ultraviolet curable resin layer is provided thereon.

Next, a substrate is placed on the cured resin layer.
The substrate is surface-treated with a surface treatment agent, and the temperature is 25 ° C to 200 ° C.
It is preferably made of a glass plate, ceramic or the like which has been baked at 30 ° C. for 30 minutes to 3 hours, and is laminated on the ultraviolet curable resin layer of the master mold 4 with the surface-treated surface facing downward. Then, the resin is cured by irradiation with ultraviolet rays. Examples of the ultraviolet irradiation means include an ultraviolet fluorescent lamp, a mercury lamp, and a metal halide lamp.

Thus, a transfer master having an uneven scale pattern made of the ultraviolet curable resin is prepared. The transfer master is subjected to electroforming having a hardness higher than that of the transfer master, for example, nickel. An extremely accurate stamper can be obtained by peeling off this electroforming mold. This product is flexible and can be attached to a roll or the like and used as a roll stamper.

Next, a method of manufacturing the optical scale by attaching the stamper obtained as described above to a roll will be described.

FIG. 3 is a schematic view showing an example of the method of manufacturing the optical scale of the present invention.

Reference numeral 11 is a first roll, 12 is a roll stamper, 13 is a third roll, and 14 is a T die. The molding material for the optical scale is melted at a temperature of not less than the glass transition temperature and not more than the decomposition temperature and extruded from the slit of the T die 14 with a substantially uniform thickness. The extruded molding material in a molten state is sandwiched between the first roll 11 and the roll stamper 12 to be molded into a sheet, and at the same time, the scale pattern on the surface of the stamper 15 attached to the surface of the roll stamper 12 is transferred. It The optical scale sheet 16 thus formed is conveyed by the third roll 13 and is conveyed to the next step. FIG. 6 is a schematic view of this optical scale.

The molding material used for producing the optical scale of the present invention may have a light transmittance of 50% or more at the wavelength of the light used, but 70% or more from the viewpoint of light utilization. Those of are preferably used. Among them, polyimide resin, polysulfone resin, polyetheretherketone resin, polycarbonate resin, amorphous polyolefin resin, acrylic resin, styrene resin, vinyl resin, PET resin, ABS resin, etc. are preferable from the viewpoint of mechanical strength and optical characteristics. Used for. Furthermore, in the present invention, the roll stamper and the first,
The base material of the third roll is preferably one having high hardness, good thermal conductivity, and easy peripheral mirror processing, and examples thereof include steel, chrome steel, aluminum, aluminum alloys, mold steel ( Aging steel), phosphor bronze, stainless steel and the like can be used. Further, it is preferable that the surfaces of the roll stamper and the base materials of the first and third rolls are mirror-finished by chrome or nickel plating.

[0052]

EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to this embodiment.

(First Example) Hardness 4 obtained by double-side polishing of 480 × 200 × 20 mm as a material for a master type master.
65 glass plates were prepared, and a 1 vol% methanol solution of silane coupling agent (trade name: A-17
4; spin coated with Nippon Unicar Co., Ltd., 70 ° C
After baking in an oven for 2 hours, an acrylic resin having a hardness of 17 was laminated as a soft layer with a thickness of about 50 μm. The price of the master mold material thus obtained was about 1/10 of that of the conventional mold material.

Next, the tip as shown in FIG.
Using a flat trapezoidal diamond cutting tool 6 with a width of m, grind 4700 trapezoidal grooves at a feed pitch of 70.6 μm,
A master mold 10 having a shape as shown in FIG. 5 was produced. The time required for processing was 16 hours, which was about one fifth of the conventional time. After the release agent is applied to this surface, 30 parts of urethane acrylate, 67 parts of neopentyl glycol-modified trimethylolpropane diacrylate, and 3 parts of 1-hydroxycyclohexyl phenyl ketone are sufficiently degassed from the ultraviolet curable resin. 30g was dripped.

Next, 1 v of silane coupling agent was applied to one side.
An ol% methanol solution (trade name: A-174; manufactured by Nippon Unicar Co., Ltd.) was spin-coated and baked in an oven at 70 ° C. for 2 hours to obtain a size of 500 × 220 × 15.
Of the metal halide lamp (trade name: UVC-2533) at the time when the UV curable resin spreads to the outer peripheral portion, by preparing the glass plate of No. 3 above and slowly stacking the silane coupling-treated surface on the above UV curable resin downward. The resin was cured by irradiating it with ultraviolet rays under the conditions of 160 W / cm ² and a lamp distance of 130 mm using USHIO INC. Then, this was peeled off to obtain a glass master disk on which a concavo-convex scale pattern made of an ultraviolet curable resin having a hardness of 25 was transferred and formed on a glass substrate having a hardness of 465. The glass master was placed on a sample stage of a sputtering device (trade name: SPF-530H; manufactured by Nichiden Anelva Co., Ltd.). The inside of the chamber is evacuated, and the ultimate vacuum is 4.0 × 10 Pa, the Ar gas pressure is 1.2 Pa, the RF power is 1 kW, and the glass master rotation speed is 1.
Reverse sputtering was performed for 5 minutes under the condition of 0 rpm. Next, under the same conditions, a DC power of 0.5 kW was used to sputter-deposit nickel to a thickness of 0.11 μm. Then 200μ
The back surface was polished by electroforming nickel up to a thickness of m. After peeling off this nickel mold in a clean room and attaching a protective film to the effective portion of the pattern, 470
The roll stamper 12 was cut into a size of 180 mm and the fixtures 8 and 9 were attached to the short sides of both ends to obtain a roll stamper 12 having a shape as shown in FIG. 7.

Then, the protective film was peeled off, and the size 4
After attaching two stampers of the above shape to a grooved roll having a diameter of 320 mmφ provided with two fixing tool mounting grooves through a polyimide film having a thickness of 70 × 178 mm and a thickness of 100 μm, the grooves between the fixing tools are made of silicone resin (trade name). : KE1
204A, B; 10 by filling with Shin-Etsu Chemical Co., Ltd.
After curing at 0 ° C. for 30 minutes, the excess resin that had been squeezed was removed by a cutter to produce a roll stamper 12.

The roll stamper 12 was attached to the apparatus as shown in FIG. 3, and the T die 14 was used to pass the bisphenol A-based polycarbonate (trade name: S-2000R;
A resin sheet manufactured by Mitsubishi Gas Chemical Co., Inc. was extruded to manufacture a continuous optical scale sheet 16 having a thickness of 0.3 mm and a width of 250 mm.

As molding conditions, the temperature of the T-die 14 is set to 32.
5 ° C., surface temperature of roll stamper 12: 140 ° C., resin sheet conveying speed: 4 m / min, resin extrusion amount: 22
The continuous molding was performed for 4 hours by adjusting the pressure to be kg / h. 8m width for optical scale molded in this way
A signal evaluation test was carried out by punching out to a size of m length 450 mm, but the fluctuation range of the signal amplitude was within ± 5%.

The transfer accuracy was 95% or more, and a very high quality optical scale could be obtained in a short time and in a large amount.

In the present embodiment, the transfer accuracy is set with a stylus type step measuring device (trade name: Alphastep 200; manufactured by Tencor Instruments Co., Ltd.) with a needle pressure of 3 mg, a scanning range of 400 μm and a scanning time of 40 seconds. With reference to the value A obtained by measuring the width of the light transmitting part of the glass master,
Ratio a of the width of the light transmitting portion on the molded scale to the measured value a
It was evaluated by the value of / A.

(Second Embodiment) As a material for a master type master, a hardness of 480.times.200.times.10 mm polished on both sides and having a hardness of 9
A nickel plate of No. 0 was prepared, the entire surface was covered with copper by plating, and gold having a hardness of 20 was coated with a thickness of about 30 μm as a soft layer on one surface thereof. Next, use a diamond bite with a right-angled tip and feed at a feed pitch of 70.6 μm
700 V-grooves were ground to prepare a master mold 4 having a shape as shown in FIG. The time required for processing was 16 hours.

This master mold was attached to an electroforming holder, and nickel was electroformed to a thickness of 200 μm.
I got a shape like. The thickness unevenness at this time was about 10 μm less than that of the conventional method. Also, there is almost no warpage that occurs when using a conventional glass master,
Even when performing backside polishing, setting on the polishing machine was easy, and the processing cost was reduced. After that, a stamper was prepared in the same manner as in the first embodiment, and then a roll stamper was prepared and attached to a molding machine.

Bisphenol A type polycarbonate (trade name: H-3000R; Mitsubishi Gas Chemical Co., Inc.)
A continuous optical scale sheet having a thickness of 0.6 mm and a width of 250 mm under the same conditions as in Example 1 except that the resin sheet conveyance speed is 1.2 m / min and the resin extrusion rate is 13 kg / h. It was manufactured continuously for 6 hours. About the optical scale molded in this way, width 8 mm length 480
A signal evaluation test was carried out by punching out into a size of mm, and the fluctuation range of the signal amplitude was within ± 4% and was quite stable.

The transfer accuracy was 96% or more, and a very high quality optical scale could be obtained in a large amount in a short time.

(Third Example) Hardness 2 after double-side polishing of 490 × 200 × 10 mm as a material for a master mold master.
Twenty acid-resistant stainless steels were prepared, and solder was coated on one surface thereof with a thickness of about 30 μm as a soft layer. Next, using a super hard sword bite with a right angle tip, feed pitch 4
By grinding 9,000 V-grooves having a size of 2.4 μm, a master die having the same shape as that of the second embodiment and a fine pitch was produced. The time required for processing was 34 hours.

This master mold was attached to an electroforming holder, and nickel was electroformed to a thickness of 200 μm. The thickness unevenness at this time was about 10 μm less than that of the conventional method. In addition, there is almost no warpage that occurs when a conventional glass master is used, and even when backside polishing is performed, the setting on the polishing machine is easy and the processing cost can be reduced. After that, a stamper was prepared in the same manner as in the first embodiment, and then a roll stamper was prepared and attached to a molding machine.

The conveyance speed of the resin sheet is 2.0 m / mi
n, the first except that the resin extrusion rate is 22 kg / h
Thickness of 0.6 mm and width of 250 mm under the same conditions as in Example
Of continuous optical scales were manufactured. The thus-formed optical scale was punched into a size of 8 mm in width and 480 mm in length, and a signal evaluation test was conducted. The fluctuation range of the signal amplitude was within ± 4% and was quite stable.

The transfer accuracy was 96% or more, and a very high precision and high quality optical scale could be obtained in a short time and in a large amount.

When an optical encoder was produced using the optical scale thus obtained, the signal output was stable, and the output was 2 more than that using the conventional silver salt film.
It was improved by 0% or more. Therefore, the output of the light emitting diode is sufficient to be 80% or less of that of the conventional one, and the life can be extended by lowering the operating current. Alternatively, by using an inexpensive low-power light emitting diode, a high-performance and inexpensive optical encoder can be manufactured, so that the design range of the optical encoder is expanded and the optical encoder can be used in various devices.

[0070]

As described above, according to the method of manufacturing a master mold for an optical scale of the present invention, when a master mold for an optical scale is manufactured, a master having a smooth surface has a hardness higher than that of the master. By providing a low soft layer and forming a scale pattern by cutting the soft layer, only the soft layer can be selectively cut, so that the master mold for an optical scale can be manufactured accurately and at low cost. I can.

Further, of the above master molds, a master mold and a soft layer, both of which have an ionization tendency less conductive than the metal used for electroforming, are made of a conductive material, and the master mold is subjected to electroforming-backside polishing directly or after releasing treatment. -Peeling-Trimming-Fixing device By the manufacturing method which has the process of welding, the conductivity is better than the conventional sputtered film, and since the electroconducting treatment is not particularly required at the time of electroforming, the stamper can be manufactured accurately and at low cost. It can be manufactured.

Further, since the stamper manufactured by the above manufacturing method has better conductivity on the surface of the master die than the conventional sputtered film, the film thickness distribution during electroforming is good and the time required for the polishing step is short. It has the advantages of low cost and low durability due to low stress caused by polishing. In addition, the unevenness scale pattern formed by the ultraviolet curing resin obtained by transferring from a master mold having a pattern made of a soft layer having a hardness lower than that of the master is formed on the pattern surface of the transfer master having a higher hardness than the transfer master. A highly accurate stamper can be obtained at low cost by performing electroforming.

Further, by molding the optical scale by the extrusion molding method using the stamper manufactured by the above manufacturing method, it becomes possible to provide an optical scale which is cheaper and more accurate than the conventional one.

By using the above optical scale, it is possible to reduce the cost of the optical system as compared with the conventional one, and it is possible to provide a very inexpensive optical encoder, which can be used for inexpensive general-purpose printers and other devices. It has become possible to equip a digital encoder and provide equipment with even better cost performance.

[Brief description of drawings]

FIG. 1-a, 1-b, 1-c are schematic views showing an example of a method for manufacturing a master mold of the present invention.

2A to 2C are schematic views showing an example of a manufacturing process of the stamper for optical scale molding of the present invention.

FIG. 3 is a schematic perspective view showing an example of an apparatus for molding an optical scale using the stamper for molding an optical scale of the present invention.

FIG. 4 is a schematic view showing an example of the shape of a diamond bite used for producing the master die of the present invention.

FIG. 5 is a schematic perspective view showing an example of the shape of a master die used for producing the stamper for optical scale molding of the present invention.

FIG. 6 is a schematic view showing an example of the entire shape of a stamper used for producing the roll stamper for optical scale molding of the present invention.

FIG. 7 is a schematic view showing an overall shape of an optical scale forming roll stamper used in an apparatus for forming an optical scale.

FIG. 8 is a schematic cross-sectional view showing an example of an apparatus for molding an optical scale using the stamper for molding an optical scale of the present invention.

[Explanation of symbols]

 1 Soft Layer 2 Master 3 Bit 4 Master Type 5 Electroformed Layer 6 Diamond Bit 7 Stamper 8, 9 Fixture 10 Master Type 11 1st Roll 12 Roll Stamper 13 3rd Roll 14 T Die 15 Stamper 16 Molded Optical Scale Sheet

Claims (13)

[Claims] 1. A master mold for optical scale molding, characterized in that a soft layer having a hardness lower than that of the master is provided on a master having a smooth surface, and the soft layer is cut to form a scale pattern. Method. 2. The method for producing a master mold for optical scale molding according to claim 1, wherein the master is a glass or ceramic plate. 3. The method for producing a master mold for optical scale molding according to claim 1, wherein the master is a metal or alloy plate. 4. The method for producing a master mold for optical scale molding according to claim 1, wherein the soft layer is a resin. 5. The method for producing a master mold for optical scale molding according to claim 1, wherein the soft layer is a soft metal or a soft alloy. 6. The method for producing a master mold for optical scale molding according to claim 1, wherein the difference in hardness between the master and the soft layer is 50 or more in Vickers hardness. 7. The method for producing a master mold for optical scale molding according to claim 1, wherein a metal, an alloy or a conductive substance having an ionization tendency smaller than that of a metal used for electroforming is used for both the master and the soft layer. 8. The method for producing a master mold for optical scale molding according to claim 7, wherein the metal used for electroforming is nickel. 9. A master mold for optical scale molding, comprising a pattern of a soft layer having a hardness lower than that of the master on a smooth master. 10. A conductive soft layer having a smooth surface and having an ionization tendency smaller than that of the metal used for electroforming is provided with a conductive soft layer having a smaller ionization tendency than that of the metal used for electroforming, and then the soft layer. After obtaining a master mold for optical scale molding by forming a scale pattern by cutting, a method for producing an optical scale molding stamper characterized by directly subjecting the surface of the formed pattern to electroforming of metal. . 11. An ultraviolet curable resin layer is laminated on the pattern surface of the master mold for optical scale molding according to claim 9,
The resin layer is cured by irradiating with ultraviolet rays to obtain a transfer master having an uneven scale pattern formed by the ultraviolet curable resin, and then the scale pattern surface of the transfer master is electroformed with a metal having a higher hardness than the transfer master. A method for manufacturing a stamper for optical scale molding, comprising: 12. The method for manufacturing an optical scale molding stamper according to claim 10, wherein the metal used for electroforming is nickel. 13. A thermoplastic resin heated to a predetermined temperature by a means for extruding a thermoplastic resin while rotating a roll die having a scale pattern on its peripheral surface and a roll arranged opposite to the roll die at a desired speed. A continuous manufacturing method of an optical scale, comprising a step of supplying a resin between the roll die and the roll, and a step of transferring the scale pattern by sandwiching the thermoplastic resin between the roll die and the roll. 13. A continuous manufacturing method of an optical scale according to claim 10, wherein a roll mold is manufactured by using the stamper according to claim 10 or 11.