JP2012068132A - Method for manufacturing optical scale - Google Patents

Abstract

An optical scale having a diffraction grating film with a uniform film thickness is manufactured.
In a method of manufacturing an optical scale 1 having at least a base substrate 3 and a diffraction grating film 5 having a diffraction grating 4 formed on the base substrate 3, a resin 11 constituting the diffraction grating film 5 is used. After coating on the base substrate 3 and extending uniformly, the resin 11 is cured to form the resin layer 13, the diffraction grating 4 is formed on the resin layer 13 on the base substrate 3, and the diffraction grating film 5 is formed. Form.
[Selection] Figure 1

Description

  The present invention relates to an optical scale manufacturing method capable of forming a diffraction grating film of an optical scale used in a position detection device with a uniform film thickness.

  2. Description of the Related Art Conventionally, an optical displacement measuring device including an optical scale and a detection head is known as a position detecting device capable of performing precise measurement of linear displacement and angular displacement. This optical displacement measuring apparatus can detect the relative position of a movable part such as a machine tool or a semiconductor manufacturing apparatus with high accuracy.

  In general, an optical displacement measuring apparatus includes an optical scale fixed to a member that detects displacement of a movable part and formed with a diffraction grating, and a detection head that detects the displacement of the optical scale. The detection head is movable along the optical scale.

  The detection head has a light source for irradiating the optical scale with a light beam and a light detection unit for detecting diffracted light transmitted through the optical scale or reflected by the optical scale. The light received by the light detection unit The movement of the optical scale is detected by the change of the signal. In this optical displacement measuring apparatus, the displacement of a movable part such as a machine tool or a semiconductor manufacturing apparatus can be known from the displacement of the optical scale.

  Here, as an optical scale used in such an optical displacement measuring device, Patent Document 1 discloses a substrate on which a resin layer on which a diffraction grating is formed and a protective group such as glass on which a reflective film is formed. A material having a structure in which a resin layer and a reflective film are placed inside with an adhesive layer interposed therebetween is described. In this optical scale, the resin layer on which the diffraction grating is formed by the protective base material is prevented from being stained or scratched. In an optical scale using such an adhesive layer, a reading error occurs due to uneven thickness of the adhesive layer.

  Therefore, Patent Document 2 discloses a configuration in which a hologram grating, a reflection film, an adhesive layer, and a protective substrate are laminated in this order on the substrate, that is, an adhesive layer is interposed between the hologram grating and the reflection film. No reflective optical scale is described. Since this optical scale does not have an adhesive layer, there is no problem of reading error due to uneven thickness of the adhesive layer. However, in this optical scale, the light that has passed through the hologram grating is reflected by the reflection layer, and is again transmitted through the hologram grating. A reflection film is attached to the grating surface of the hologram grating and reflected by that portion. The thickness unevenness of the portion forming the film affects the measurement accuracy.

For this reason, as an optical scale, it is calculated | required that there is no film thickness nonuniformity in the resin layer in which the diffraction grating is formed, and is uniform.

Japanese Patent Laid-Open No. 5-232318 JP 2000-121392 A

  Therefore, the present invention has been proposed in view of such conventional situations, and an object of the present invention is to provide an optical scale manufacturing method for forming a diffraction grating film having a uniform film thickness on a base substrate. To do.

  An optical scale manufacturing method according to the present invention that achieves the above-mentioned object is an optical scale manufacturing method having at least a base substrate and a diffraction grating film having a diffraction grating formed on the base substrate. After applying the resin that constitutes the grating film on the base substrate and extending it uniformly, the resin is cured to form a resin layer, and a diffraction grating is formed on the resin layer on the base substrate to form the diffraction grating film. It is characterized by forming.

  An optical scale manufacturing method according to the present invention that achieves the above-mentioned object is an optical scale manufacturing method having at least a base substrate and a diffraction grating film having a diffraction grating formed on the base substrate. The resin constituting the grating film is sandwiched between the base substrate and the stamper on which the mold corresponding to the diffraction grating is formed. After the resin is uniformly stretched, the resin is cured, and the base substrate and the cured resin are stamped. And a diffraction grating film having a diffraction grating formed on a base substrate is formed.

  In the present invention, a resin layer having a uniform film thickness is formed by applying a resin constituting a diffraction grating film on a base substrate and uniformly extending the resin, and then curing the resin to form a resin layer. Can do. Thereby, in this invention, the optical scale which has a diffraction grating film | membrane with a uniform film thickness on a base base material can be manufactured easily.

It is sectional drawing which shows the diffraction state by the optical scale of 1st Embodiment obtained by the manufacturing method of the optical scale to which this invention is applied. It is sectional drawing which shows the state which the wave | undulation has generate | occur | produced in the diffraction grating film | membrane. It is sectional drawing explaining the manufacturing method of the optical scale to which this invention is applied, (A) is sectional drawing which shows the state which has extended | stretched resin between a base base material and a glass plate with a roll, (B) is It is sectional drawing which shows the state which peels a base base material and a resin layer from a glass plate. It is sectional drawing explaining the method of forming a diffraction grating film | membrane using a base base material and a glass plate, (A) is sectional drawing which shows the state which pinched | interposed resin, (B) is a base from a glass plate. It is sectional drawing which shows the state which peels a base material and a resin layer. It is sectional drawing of the optical scale which has a sinusoidal diffraction grating. It is sectional drawing explaining the method of forming a diffraction grating film | membrane using a stamper, (A) is sectional drawing which shows the state which extended | stretched the resin between a base base material and a stamper with a roll, (B) These are sectional drawings which show the state which peels a base base material and a resin layer from a stamper.

  Hereinafter, an optical scale manufacturing method to which the present invention is applied will be described in detail with reference to the drawings.

  In the position detection system, for example, when measuring linear displacement, as shown in FIG. 1, the optical scale 1 has a long shape and is formed with a diffraction grating 4, and moves relative to the optical scale 1. And a possible encoder 2. In the position detection system, laser light is irradiated on the physical irregularities of the diffraction grating 4 formed on the optical scale 1, and the rotation of the phase of the diffracted light accompanying the change in the relative position between the optical scale 1 and the encoder 2 Read and detect the position. This position detection system is excellent with a resolution of nm or less.

  As shown in FIG. 1, an optical scale 1 used in such a position detection system includes a base material 3 that is long in the direction of the measurement axis X, and a rectangular diffraction grating 4 on the base material 3. The formed diffraction grating film 5, the reflective film 6 formed on the diffraction grating film 5, the adhesive film 7 formed on the reflective film 6, and the protective film laminated via the adhesive film 7 A substrate 8.

  When the optical scale 1 is manufactured, if the diffraction grating film 5 on which the diffraction grating 4 is formed has no film thickness unevenness and can be formed uniformly, the occurrence of output unevenness can be prevented. When waviness due to film thickness unevenness occurs in the diffraction grating film 5, waviness on the reflecting surface is caused by position detection accuracy due to the film thickness unevenness in the diffraction grating film 9 a like the optical scale 9 shown in FIG. 2. Will be affected. In the optical scale 9, the base substrate, the reflective film, the adhesive film, and the protective substrate are the same as the base substrate 3, the reflective film 6, the adhesive film 7, and the protective substrate 8 of the optical scale 1 described above. Therefore, the same reference numerals are given.

  The position detection error can be corrected with a correction coefficient or the like, but the smaller the undulation, the smaller the correction coefficient, and the higher the handling and reliability. The undulation of the diffraction grating film 5 can be suppressed by reducing the thickness unevenness of the diffraction grating film 5. One effective means for reducing film thickness unevenness when the diffraction grating film 5 is formed of resin is to make the film thickness as thin as possible. As a film forming method, a spin coating method, a coating method using a capillary phenomenon, or the like can be considered. In the present invention, the diffraction grating film 5 is uniformly and thinly formed by the method described below.

  In the present invention, the diffraction grating film 5 is formed on the base substrate 3 as follows, thereby forming the diffraction grating film 5 uniformly without any film thickness unevenness and preventing the occurrence of output unevenness. As a method for uniformly forming the film thickness of the diffraction grating film 5, there is a method in which a resin 11 is applied on the base substrate 3 and the resin 11 is uniformly stretched to form a spin coat, capillary coat, or base substrate. A method of sandwiching a resin between a flat glass plate, a method of sandwiching a base substrate and a glass plate, placing a weight on a flat glass plate, a method of pressure bonding with a roll when sandwiching a resin between a substrate and a glass plate, There are methods such as sandwiching or roll pressing while applying heat. In any method, the resin 11 can be uniformly applied on the base substrate 3.

  For example, as a method using a flat glass plate, there are the following methods. As shown in FIG. 3A, the base material 3 is pressed against the glass plate 10 with a resin 11 constituting the diffraction grating film 5 interposed between the flat glass plate 10 and the base material 3. In this way, the rubber roll 12 is moved while being pressed onto the base substrate 3, thereby extending the resin 11 and extending the resin 11 between the base substrate 3 and the flat glass plate 10 positioned in parallel. To. Thus, by using the flat glass plate 10 and the rubber roll 12, the resin 11 is thinly and uniformly stretched. The rubber roll 12 may be moved on the glass plate 10.

  And as shown in FIG.3 (B), after hardening the resin 11 extended thinly between the base base material 3 and the glass plate 10 and forming the resin layer 13, from the glass plate 10, the base base material 3 and By peeling off the resin layer 13, a thin and uniform resin layer 13 is formed on the base substrate 3. The film thickness of the resin layer 13 is adjusted to a desired film thickness by adjusting the thickness of the glass plate 10 and the pressing force of the rubber roll 12. For example, when the thickness of the glass plate 10 is about 500 mPa · s when the thickness is 1 mm, the resin layer 13 having a thickness of 3 μm or less can be formed on the base substrate 3. Further, in this method, mixing of bubbles can be prevented. In this method of forming the diffraction grating film 5, the resin layer 13 is easily peeled off from the glass plate 10 by performing a release treatment on the surface of the glass plate 10 on the side in contact with the resin 11, so that the resin layer 13 becomes a base substrate. The resin layer 13 can be formed on the base substrate 3.

  Next, a rectangular uneven diffraction grating 4 is formed on the resin layer 13 on the base substrate 3 formed as described above. The diffraction grating 4 is formed on the diffraction grating film 5 shown in FIG. 1 by exposing the resin layer 13 with, for example, hologram exposure, laser drawing, a mask, and developing.

  In the above-described method of forming the diffraction grating film 5, the rubber roll 12 is used. However, as shown in FIG. 4, the diffraction grating film 5 can be formed uniformly even using only the flat glass plate 10.

  When the rubber roll 12 is not used, as shown in FIG. 4A, the base substrate 3 and the flat glass plate 10 are in parallel with each other between the base substrate 3 and the glass plate 10. The resin 11 constituting the diffraction grating film 5 is sandwiched between and the resin 11 is cured in the sandwiched state. As a result, as shown in FIG. 4B, the thickness of the resin layer 14 formed by curing the resin 11 can be made uniform, and the base substrate 3 and the resin layer 14 are peeled off from the glass plate 10. Thus, the resin layer 14 having a uniform film thickness can be formed on the base substrate 3. The resin layer 14 adjusts the thickness of the resin layer 14 by placing a weight on the base substrate 3 as necessary with the resin 11 sandwiched between the base substrate 3 and the glass plate 10. be able to.

  However, the use of the rubber roll 12 as described above is preferable because the resin 11 can be stretched more uniformly and thinly, and the film thickness of the diffraction grating film 5 can be made thin and uniform.

  Next, the reflective film 6 is formed on the diffraction grating film 5 formed using the rubber roll 12 described above. The reflection film 6 is formed by forming a metal film on the surface of the diffraction grating film 5 by vapor deposition or sputtering, for example.

  Next, an adhesive film 7 for bonding the protective substrate 8 is formed on the reflective film 6. The adhesive film 7 is formed by applying an adhesive to the reflective film 6.

  And the optical scale 1 can be manufactured by bonding the protective substrate 8 through the adhesive film 7.

  In the manufacturing method of the optical scale 1 as described above, since the resin 11 can be applied on the base substrate 3 and uniformly stretched, the film thickness of the diffraction grating film 5 formed by curing the resin 11 can be reduced. It can be made uniform. Thereby, in the manufacturing method of this optical scale 1, since the diffraction grating film 5 can be made thin and uniform, the output scale does not occur, and the optical scale 1 with high measurement accuracy and high reliability can be manufactured. .

  In particular, when the glass plate 10 and the rubber roller 12 are used as described above, since the rubber roller 12 is moved while being pressed onto the base substrate 3, the resin 11 can be stretched more uniformly and thinly, and the diffraction grating film 5 can be formed more uniformly and thinly. Thereby, when the glass plate 10 and the rubber roller 12 are used, it is possible to further prevent the occurrence of output unevenness and to manufacture the optical scale 1 with high measurement accuracy and high reliability.

  Further, in the method of manufacturing the optical scale 1, even when the length of the optical scale 1 is long, for example, about 600 mm, when the rubber roll 12 is used, compared to the case where the diffraction grating film 5 is formed by a spin coater, A uniform diffraction grating film 5 can be formed at low cost without requiring large-scale equipment.

  Here, in the manufacturing method of the optical scale 1 described above, the base substrate 3, the diffraction grating film 5, the reflective film 6, the adhesive film 7, and the protective substrate 8 are specifically formed with the optical scale 1 having the following configuration. Can be manufactured.

  The base substrate 3 can be a generally optical scale base substrate such as glass or ceramic that is elongated in the measurement axis X direction.

  The diffraction grating film 5 includes, for example, an acrylic or epoxy ultraviolet curable resin, an acrylic or epoxy thermosetting resin, and various energy ray curable resins that are activated by electron beams or X-rays. Such resists and emulsions can be used. In the diffraction grating 4, it is preferable that the optical depth from the top of the convex portion of the diffraction grating 4 to the bottom of the concave portion is approximately ¼ of the reference wavelength (λ). When the depth of the diffraction grating 4 is λ / 4, the reflection intensity of the 0th-order diffracted light is reduced due to the effect of preventing reflection, and the energy is dispersed to the 1st-order diffracted light and the like. Can be raised. Therefore, the optimum depth of the diffraction grating 4 is determined by the angle of the incident light, but is approximately ¼ of the wavelength.

  The film thickness of the diffraction grating film 5 can be reduced to 10 μm or less and further to 3 μm or less by the method for manufacturing the optical scale 1 described above. Here, the film thickness of the diffraction grating film 5 refers to the distance from the surface 5a on the base substrate 3 side of the diffraction grating film 5 to the apex of the convex portion of the diffraction grating 4 shown in FIG. For example, if the film thickness is about 10 μm, the thickness unevenness can be reduced to half or less of the film thickness, and the occurrence of the film thickness unevenness can be easily suppressed. Furthermore, when the film thickness is 3 μm or less, the film thickness unevenness can be sufficiently reduced. Since the surface accuracy level of the glass of the base substrate 3 is practically about ± 10 μm, it is one guideline to set the film thickness of the diffraction grating film 5 to about 10 μm.

  The diffraction grating film 5 can have a film thickness of 10 μm or less by the above-described method of forming the diffraction grating film 5, thereby suppressing the occurrence of film thickness unevenness and improving the adhesion with the base substrate 3. Since it can also be 3 micrometers or less, there is almost no film thickness nonuniformity, it is substantially uniform, and adhesiveness with the base base material 3 is higher.

  The reflective film 6 is preferably formed on the diffraction grating film 5 and has a high reflectance with respect to the wavelength of the laser light source used in the encoder 2. As the reflective film 6, a metal film having a high reflectance is generally used, but at the same time, the reliability of the film is also required. For example, when used in the near infrared region such as 790 nm, a metal film having a high red reflectance is preferable, and is formed of a metal film such as gold, platinum, copper, copper alloy, aluminum, aluminum alloy, silver, silver alloy, or the like. In practice, it is preferably formed of a silver palladium alloy. Among the metal films described above, pure metals such as gold, platinum, copper, and silver are highly reflective, and copper alloys and silver alloys are not oxidized or sulfided to modify the film. Even if gold and platinum are not alloys, they are sufficiently resistant to oxidation and the like. Gold or the like is a material that is highly reliable, easy to form, and easy to handle. Gold and platinum are expensive but have good environmental resistance. As the silver alloy, a silver-palladium alloy with reduced sulfidation is practically suitable, and the reflectance of the encoder 2 with respect to the 790-nm laser light is over 95% as in the case of gold, and the amount of sputter target is as low as 1/10 or less. Cost. For example, when the configuration of the encoder 2 causes the laser beam to hit the diffraction grating surface twice, the influence of the reflectivity on the output of the encoder 2 is effective by the square. In the case of such a configuration of the encoder 2, the higher the reflectivity, the better. For example, since the encoder output is reduced to 49% on the reflective surface where the reflectivity is reduced to 70%, practically 70% or more. The reflectance is more preferably 90% or more. In order to improve the adhesion between the diffraction grating film 5 and the reflection film 6, it is preferable to add Cr, Ti, Si, SiOx or the like to the base.

  The adhesive film 7 is interposed between the reflective film 6 and the protective base material 8, and adheres the protective base material 8 onto the reflective film 6. For the adhesive film 7, a transparent adhesive such as epoxy is used to transmit the laser light and diffracted light emitted from the encoder 2. As the adhesive film 7, it is preferable to use a film having good adhesion to the reflective film 6 and the protective substrate 8. The adhesive film 7 has a wide range of choices because it is only necessary to select a resin having good adhesion to glass and transparency. For example, in the case of an epoxy-based transparent adhesive, in many cases, adhesion to glass is sufficiently good.

  The protective substrate 8 is laminated on the reflective film 6 with the adhesive film 7 interposed therebetween, and prevents the diffraction grating film 5 and the reflective film 6 from being damaged due to peeling or cracking, contact with external parts, or the like. is there. The protective substrate 8 is formed in a long shape in the direction of the measurement axis X, like the base substrate 3, so that the entire diffraction grating film 5 and the reflective film 6 can be covered. A transparent member such as glass is used for the protective substrate 8 in order to transmit the laser light and diffracted light emitted from the encoder 2.

  The optical scale 1 having such a structure is manufactured by the method for manufacturing the optical scale 1 described above, and the film thickness of the diffraction grating film 5 is 10 μm or less, the film thickness unevenness is suppressed, and the film is uniformly formed. Therefore, the influence on the measurement accuracy due to the film thickness unevenness of the diffraction grating film 5 is suppressed, and the measurement can be performed with high accuracy.

  In the above, the manufacturing method of the optical scale 1 having the diffraction grating film 5 having the rectangular unevenness and the optical scale 1 have been described. However, as shown in FIG. 5, the reflective optical scale having the sinusoidal diffraction grating 22 is used. 20 can also be applied.

  The optical scale 20 includes a diffraction grating film 23 in which a sinusoidal diffraction grating 22 is formed on a base substrate 21, a reflection film 24 formed on the diffraction grating film 23, and a reflection film 24 on the reflection film 24. A formed adhesive film 25 and a protective base material 26 laminated through the adhesive film 25 are provided. The base substrate 21, the reflective film 24, the adhesive film 25, and the protective substrate 26 are the same as the base substrate 3, the reflective film 6, the adhesive film 7, and the protective substrate 8 of the optical scale 1 described above. Since it is a structure, detailed description is abbreviate | omitted and a different point from the scale 1 mentioned above is demonstrated.

  The optical scale 20 is manufactured in the same manner as the optical scale 1 described above by spin coating, capillary coating, a method of sandwiching a resin between a base substrate and a flat glass plate, and a base substrate. Resin by a method of placing a weight on a flat glass plate sandwiched between a material and a glass plate, a method of crimping with a roll when sandwiching a resin between a substrate and a glass plate, a method of sandwiching or roll crimping while applying heat, etc. 27 is applied uniformly.

  Similarly to the optical scale 1 described above, the glass 27 may be used to uniformly extend the resin 27 on the base substrate 21. Specifically, as shown in FIG. 3 (A), a resin 27 constituting the diffraction grating film 23 is sandwiched between the base substrate 21 and the flat glass plate 10 by using the rubber roll 12, and the base substrate 21. After the rubber roll 12 is moved while being pressed to stretch the resin 27 uniformly, the resin 27 is cured to form a resin layer 28 as shown in FIG. Then, the base substrate 21 and the resin layer 28 are peeled off from the glass plate 10, thereby forming a uniform resin layer 28 with a thin film thickness on the base substrate 21. Similar to the method of manufacturing the optical scale 1, by subjecting the surface of the glass plate 10 on the side in contact with the resin 27 to release, the resin layer 28 can be easily peeled off from the glass plate 10, and the resin layer 28 is the base. It can be made to remain on the base material 21 side, and the resin layer 28 can be formed on the base base material 21.

  Next, by using, for example, hologram exposure on the resin layer 28 constituting the diffraction grating film 23 on the base substrate 21, the shape of the diffraction grating 22 is a shape close to a sine wave as shown in FIG. To form.

  Then, the optical scale 20 can be manufactured by laminating the reflective film 24, the adhesive film 25, and the protective base material 26 on the formed diffraction grating film 23 in the same manner as the method for manufacturing the optical scale 1 described above.

  Also in the manufacturing method of the optical scale 20 as described above, since the resin 27 can be applied on the base substrate 21 and uniformly stretched, the thickness of the diffraction grating film 23 formed by curing the resin 27 is reduced. , Can be uniform. Thereby, in this manufacturing method of the optical scale 20, since the diffraction grating film 23 can be made thin and uniform, output unevenness does not occur, and the optical scale 20 with high measurement accuracy and high reliability can be manufactured. .

  In particular, when the glass plate 10 and the rubber roller 12 are used as described above, since the rubber roller 12 is moved on the base substrate 21 while being pressed, the resin 27 can be stretched more uniformly and thinly. 23 can be formed more uniformly and thinly. Thereby, when the glass plate 10 and the rubber roller 12 are used, it is possible to further prevent the occurrence of output unevenness and to manufacture the optical scale 20 with high measurement accuracy and high reliability.

  Next, as a second embodiment, as another method for manufacturing an optical scale having a rectangular diffraction grating, an optical scale having a diffraction grating film 33 having a rectangular diffraction grating 32 as shown in FIG. The manufacturing method 30 will be described. Similar to the optical scale 1 described above, the optical scale 30 is a diffraction grating film in which a long base material 31 in the measurement axis X direction and a rectangular diffraction grating 32 are formed on the base material 31. 33, a reflective film 34 formed on the diffraction grating film 33, an adhesive film 35 formed on the reflective film 34, and a protective base material 36 laminated via the adhesive film 35. .

  In the method for manufacturing the optical scale 30, as shown in FIG. 6, the diffraction grating 32 and the diffraction grating film 33 are simultaneously formed using a stamper 41. The stamper 41 is flat, and a mold 43 corresponding to the diffraction grating 32 is formed on the surface of a stamper plate 42 that is formed in a long shape like the base substrate 31.

  In the method of manufacturing the optical scale 30, a rubber roll 44 is provided so that a resin 37 constituting the diffraction grating film 33 is interposed between the base substrate 31 and the stamper 41 and the base substrate 31 is pressed against the stamper 41. Is moved while being pressed onto the base substrate 31, thereby extending the resin 37 and extending the resin 37 between the base substrate 31 and the stamper 41 positioned in parallel. Thus, by using the stamper 41 and the rubber roll 12, the resin 37 is thinly and uniformly extended. The rubber roll 44 may be moved on the stamper 41.

  Then, after the resin 37 thinly stretched between the base substrate 31 and the stamper 41 is cured and then the stamper 41 is peeled off from the cured resin 37, a diffraction grating film 33 in which the diffraction grating 32 is formed is obtained. The grating 32 and the diffraction grating film 33 can be easily formed simultaneously. In this method of forming the diffraction grating film 33, the resin 37 is left on the base substrate 31 side by performing a mold release process on the surface of the stamper 41 that is in contact with the resin 37. A diffraction grating film 33 can be formed.

  Further, when the diffraction grating film 33 is formed using the stamper 41 as described above, it is preferable to use an ultraviolet curable resin (UV curable resin) or the like as the resin constituting the diffraction grating film 33. The UV curable resin has various requirements such as the ability to precisely transfer the shape of the stamper 41, good releasability from the stamper 41, no damage to the stamper 41, short curing time, no change over time, etc. The level is high.

  The method of uniformly applying the resin 37 on the base substrate 31 is not limited to the method using the rubber roll 12 described above, but the resin 37 is applied to the entire surface of the stamper 41 so that the resin 37 is attached to the base substrate 31. The resin 37 may be placed on the applied stamper 41 and the resin 37 is sandwiched between the stamper 41 and the base substrate 31, or a heavy stone is placed on the base substrate 31, and the resin 37 may be uniformly extended.

  Next, in the same manner as the method for manufacturing the optical scale 1 described above, the optical scale 30 is manufactured by laminating the reflective film 34, the adhesive film 35, and the protective substrate 36 on the diffraction grating film 33.

  In the manufacturing method of the optical scale 30 as described above, the base substrate 31 is pressed against the stamper 41 by the rubber roll 44, thereby forming the diffraction grating film 33 having a thin film thickness and a uniform diffraction grating 32 formed simultaneously. be able to. In this method of manufacturing the optical scale 30, it is possible to manufacture the optical scale 30 with a thin and uniform diffraction grating film 33, no output unevenness, and high measurement accuracy and high reliability.

  In the method for manufacturing the optical scales 20 and 30 described above, the base substrates 21 and 31, the diffraction grating films 22 and 32, the reflection films 24 and 34, the adhesive films 25 and 35, and the protective base materials 26 and 36 are optically The optical scales 20 and 30 having the same configuration as that of the scale 1 can be manufactured. Note that the optical scale 20 having a sinusoidal diffraction grating has a wider band than the rectangular optical scales 1 and 30 and has a robust characteristic that has little influence on measurement even if the reference light is slightly shifted. Become.

  Moreover, the optical scales 1, 20, and 30 obtained by the manufacturing method as described above can be used for detecting the relative position of the movable part of the measuring instrument, the machine tool, or the semiconductor manufacturing apparatus.

  The optical scales 1, 20, and 30 described above are reflective optical scales, but a transmissive optical scale can also be realized by a transfer method. In the case of a transmissive optical scale, for example, the refractive index of the resin constituting the diffraction grating film is made sufficiently higher than the adhesive film or glass that bonds the protective substrate, By making the light diffract, a transmissive optical scale is possible.

  DESCRIPTION OF SYMBOLS 1 Optical scale, 2 Encoder, 3 Base substrate, 4 Diffraction grating, 5 Diffraction grating film, 6 Reflective film, 7 Adhesive film, 8 Base material for protection, 10 Glass plate, 11 Resin, 12 Rubber roll, 13 Resin layer

Claims (2)

In a method for producing an optical scale having at least a base substrate and a diffraction grating film having a diffraction grating formed on the base substrate,
The resin constituting the diffraction grating film is applied onto the base substrate and uniformly stretched, and then the resin is cured to form a resin layer. The diffraction grating is applied to the resin layer on the base substrate. A method for producing an optical scale, comprising forming the diffraction grating film. In a method for producing an optical scale having at least a base substrate and a diffraction grating film having a diffraction grating formed on the base substrate,
The resin constituting the diffraction grating film is interposed between the base substrate and a stamper provided with a mold corresponding to the diffraction grating on a flat stamper plate, and the resin is uniformly stretched. A method for producing an optical scale, comprising: curing, peeling the base substrate and the cured resin from the stamper, and forming the diffraction grating film having the diffraction grating formed on the base substrate.

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