WO2019163630A1 - Method for producing mold - Google Patents

Method for producing mold Download PDF

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Publication number
WO2019163630A1
WO2019163630A1 PCT/JP2019/005312 JP2019005312W WO2019163630A1 WO 2019163630 A1 WO2019163630 A1 WO 2019163630A1 JP 2019005312 W JP2019005312 W JP 2019005312W WO 2019163630 A1 WO2019163630 A1 WO 2019163630A1
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WO
WIPO (PCT)
Prior art keywords
region
shape
optical element
mold
manufacturing
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Application number
PCT/JP2019/005312
Other languages
French (fr)
Japanese (ja)
Inventor
幸暢 西尾
賢元 池田
健志 谷邊
山本　和也
Original Assignee
ナルックス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by ナルックス株式会社 filed Critical ナルックス株式会社
Priority to JP2019557645A priority Critical patent/JP6681638B2/en
Priority to DE112019000913.3T priority patent/DE112019000913T5/en
Priority to CN201980013917.6A priority patent/CN111741839B/en
Publication of WO2019163630A1 publication Critical patent/WO2019163630A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/42—Moulds or cores; Details thereof or accessories therefor characterised by the shape of the moulding surface, e.g. ribs or grooves
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0012—Arrays characterised by the manufacturing method
    • G02B3/0031—Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1847—Manufacturing methods
    • G02B5/1852—Manufacturing methods using mechanical means, e.g. ruling with diamond tool, moulding
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1847—Manufacturing methods
    • G02B5/1857—Manufacturing methods using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams

Definitions

  • the present invention relates to a mold manufacturing method, and more particularly to a method for manufacturing a mold for an optical element.
  • An optical element having a corresponding shape and forming a region with higher illuminance than the surroundings by light rays is known.
  • An example of a conventional method for manufacturing the optical element is a method of covering the surface of the second portion of the optical element with a metal film. In this conventional manufacturing method, a metal film is formed only on the surface of the second portion, or a metal film is formed on the entire surface, and then the first portion of the metal film is removed by a laser or the like. Therefore, the above manufacturing method is not suitable for mass production.
  • the first portion has a substantially flat surface
  • the second portion has an optical structure that causes diffraction, diffusion, and the like of the light beam.
  • Such a mold for an optical element includes a substantially flat region corresponding to the first part of the optical element and a region corresponding to the optical structure which is the second part of the optical element.
  • a substantially flat region corresponding to the first portion of the optical element is referred to as a first region of the mold
  • a region corresponding to the optical structure which is the second portion of the optical element is referred to as the first portion of the mold. This is referred to as area 2.
  • molds for optical elements are usually manufactured by machining using a ball end mill.
  • various optical surface shapes corresponding to, for example, an aspherical surface and a free-form surface can be formed.
  • the corner R cannot be made smaller than the radius of curvature of the edge of the ball end mill. Since the minimum value of the radius of curvature of the edge of the ball end mill is about 15 micrometers, the minimum value of the corner R is about 15 micrometers.
  • molds such as a binary diffraction grating may be manufactured by resist patterning and etching.
  • resist patterning and etching for example, the corner R of the binary diffraction grating can be set to 1 micrometer or less.
  • resist patterning and etching it is difficult to form various optical surface shapes corresponding to aspherical surfaces, free-form surfaces, etc. by resist patterning and etching.
  • Patent Document 1 discloses an optical element having a portion that transmits light and a portion that blocks or diffuses light. However, Patent Document 1 does not disclose a method for manufacturing such an optical element in detail. Further, the optical element of Patent Document 1 controls the amount of light of a microscope, and has a technical problem of sharpening the boundary of a region having higher illuminance than the periphery formed on the surface by light rays that have passed through the optical element. Is irrelevant.
  • the first part which is a substantially flat surface which can sharpen the boundary of the region with higher illuminance than the surrounding formed on the surface by the light beam that has passed through the optical element, and the light beam are diffracted.
  • a method for manufacturing a mold of an optical element composed of the second portion, which is an optical structure that causes diffusion or the like, with high accuracy and high efficiency has not been developed.
  • the first part which is a substantially flat surface, which can sharpen the boundary of the area with higher illuminance formed on the surface by the light beam that has passed through the optical element, causes diffraction, diffusion, etc.
  • An object of the present invention is to diffract light into a first portion and a light beam, which is a substantially flat surface, which can sharpen the boundary of a region with higher illuminance than the surroundings formed on the surface by the light beam that has passed through the optical element.
  • An object of the present invention is to provide a method for manufacturing a mold of an optical element composed of a second portion which is an optical structure that causes diffusion or the like with high accuracy and high efficiency.
  • the method for manufacturing a mold for an optical element according to the present invention includes forming a first groove having a substantially flat bottom surface having a width of 2 micrometers or more in a first region of a surface of a substrate by resist patterning and etching. And machining a second region surrounding the first region of the surface of the substrate into a shape comprised of a surface that is not parallel to the bottom surface.
  • the first groove having a substantially flat bottom surface with a width of 2 micrometers or more is formed in the first region of the surface of the substrate by resist patterning and etching.
  • the corner R at the boundary between the flat bottom surface and the side surface can be set to 1 micrometer or less. Therefore, in the optical element manufactured from the mold, the optical corresponding to the first portion of the optical element corresponding to the first area of the mold and the second area of the mold surrounding the first area of the mold. The boundary with the second part of the element becomes sharp. As a result, when light is irradiated onto a certain surface through the optical element, a high illuminance region having a sharp boundary shape corresponding to the shape of the first region of the mold can be formed on the surface.
  • the second region of the mold surrounding the first region of the mold is a region that borders the periphery of the first region, and an optical element is manufactured by the mold, and the optical element is passed through the optical element.
  • a region formed so that when a certain surface is irradiated with light, a region having a bright boundary corresponding to the shape of the first region of the mold and having a higher illuminance than the periphery can be formed on the surface.
  • the shape of the region other than the region bordering the periphery of the first region may be any shape.
  • a shape constituted by a surface not parallel to the bottom surface of the first groove can be formed with high accuracy and high efficiency by machining. .
  • the present invention is an optical structure capable of sharpening the shape boundary formed by the light beam that has passed through the optical element and causing the light beam to be diffracted, diffused, etc., which is a substantially flat surface.
  • both resist patterning and etching and machining are appropriately combined. It is characterized by points.
  • the depth of the first groove is 30 micrometers or less, and the depth of the shape of the second region is 20 micrometers or less. is there.
  • the depth from the surface of the substrate before processing the first groove in the first region and the shape in the second region is 30 micrometers or less. Therefore, a compact optical element having a small thickness can be obtained.
  • the shape of the second region includes a periodic structure, and the period of the periodic structure is greater than the width of the bottom surface of the first groove. Is also small.
  • the portion corresponding to the second region of the optical element manufactured by the mold according to the present embodiment includes a periodic structure, and therefore can cause diffraction and diffusion of light rays.
  • the shape of the second region is a plurality of second grooves arranged so that the longitudinal directions thereof are substantially the same direction
  • the cross section perpendicular to the longitudinal direction of the second groove of the optical device shows a periodic structure.
  • the cross section of the portion corresponding to the second region of the optical element manufactured by the mold according to the present embodiment shows the periodic structure. Therefore, it is possible to cause diffraction and diffusion of light rays.
  • the shape of the second region corresponds to the diffraction grating of the optical element.
  • an optical element in which the second portion corresponding to the second region of the mold is a diffraction grating is obtained.
  • the illuminance of a region other than the high illuminance region corresponding to the first region of the mold on the surface can be adjusted by the diffraction grating.
  • the shape of the second region corresponds to the microprism array of the optical element.
  • the optical element having the microprism array in the region corresponding to the second region can be obtained by the mold manufacturing method according to the present embodiment.
  • the illuminance in a region other than the high illuminance region corresponding to the first region on the surface can be adjusted by the microprism array.
  • the shape of the second region corresponds to the microlens array of the optical element.
  • the optical element having the microlens array in the region corresponding to the second region can be obtained by the mold manufacturing method according to the present embodiment.
  • the illuminance in a region other than the high illuminance region corresponding to the first region on the surface can be adjusted by the microlens array.
  • the shape of the second region is formed by drawing.
  • the shape of the diffraction grating or the like in the second region is formed by drawing. Therefore, a shape such as a diffraction grating can be formed with high accuracy and high efficiency.
  • the shape of the second region is formed using a diamond cutting tool.
  • the first groove and the shape are formed at a corner R of 1 micrometer or less.
  • the optical element manufactured from the mold corresponds to a region corresponding to the first region and a second region surrounding the first region.
  • the boundary with the area becomes sharp.
  • FIG. 4 is a diagram illustrating a shape corresponding to a microprism array machined in a second region of a substrate.
  • FIG. 1 is a flowchart showing a method for manufacturing a mold for optical elements according to an embodiment of the present invention.
  • FIG. 2 is a diagram for explaining a method of manufacturing the mold for the optical element described above.
  • the substrate is cleaned.
  • the substrate material may be an electroless nickel phosphor plating.
  • FIG. 2A is a view showing a cross section of the substrate after cleaning.
  • step S1020 of FIG. 2 resist patterning for forming the first groove on the surface of the substrate is performed. Specifically, the second region other than the first region on the surface of the substrate is covered with a resist.
  • FIG. 2B is a diagram showing a cross section of the substrate in which a second region other than the first region on the surface of the substrate is covered with a resist.
  • etching is performed to form a first groove in the first region.
  • the etching may be ion beam etching.
  • FIG. 2C is a diagram showing a cross section of the substrate after etching. A first groove is formed in a first region on the surface of the substrate.
  • step S1040 of FIG. 2 the resist is removed.
  • FIG. 2D is a view showing a cross section of the substrate after the resist is removed.
  • a first groove is formed in the first region on the surface of the substrate.
  • the bottom surface of the first groove is substantially flat, and the width of the bottom surface of the first groove is 2 micrometers or more.
  • the bottom surface of the first groove is substantially parallel to the surface of the substrate before processing.
  • channel is 1 micrometer or more and 30 micrometers or less.
  • step S1050 of FIG. 2 the second region other than the first region is machined to form a shape composed of a surface that is not parallel to the bottom surface of the first groove.
  • the depth of the shape of the second region from the surface of the substrate before processing is not less than 0.5 micrometers and not more than 20 micrometers.
  • the depth of the shape of the first groove and the second region from the surface of the substrate before processing is 30 micrometers or less.
  • FIG. 2 (e) is a diagram showing a cross-section of a substrate after machining, that is, a mold.
  • a periodic structure is formed in the second region by machining. The machining will be described later in detail.
  • the cross section is perpendicular to the longitudinal direction of the periodic structure and the surface of the substrate before processing.
  • resist patterning, etching, and machining should be performed in this order.
  • machining is performed first, a groove having a substantially flat bottom surface cannot be formed by resist patterning and etching. If the resist is machined after the resist patterning and before the etching, there arises a problem that the shape formed by machining on the resist is deformed by the etching, and the accuracy of the shape of the mold is deteriorated.
  • FIG. 3 is a diagram showing a cross section perpendicular to the longitudinal direction of the periodic structure and the surface of the substrate before processing of the substrate after machining, as in FIG. 2 (e).
  • a groove having a substantially flat bottom surface is formed in the first region 101 of the substrate 100, and a periodic structure is formed in the second region 103 other than the first region 101.
  • the periodic structure corresponds to a diffraction grating as an example. Further, the periodic structure is configured from a surface that is not parallel to the bottom surface of the groove of the first region 101.
  • FIG. 4 is a view showing an example of an optical element formed by a mold having a cross section as shown in FIG.
  • the first portion 101 'of the optical element 100' corresponding to the first region 101 is a flat surface.
  • the second portion 103 ′ of the optical element 100 ′ corresponding to the second region 103 is a diffraction grating.
  • the first portion 101 ′ transmits the light beam without causing diffraction
  • the second portion 103 ′ which is a diffraction grating, diffracts the light.
  • the illuminance of the region 101 ′′ having a shape corresponding to the shape of the first portion 101 ′ on the surface is higher than the surrounding area. Therefore, the shape of the region 101 ′′ corresponding to the shape of the first portion 101 ′ on the surface is higher.
  • the area 101 ′′ can be identified.
  • FIG. 5 is a diagram for explaining a drawing process using a rectangular diamond tool.
  • a groove having a cross section of the same shape as the shape of the blade edge is formed by cutting the substrate 100 while moving a rectangular diamond tool 201 linearly.
  • Such a processing method is referred to as a drawing process.
  • the groove depth is about 1 micrometer when the groove width on the surface is 10 micrometers.
  • FIG. 6 is a photograph of the cutting edge of the rectangular diamond tool 201.
  • FIG. 7 is a diagram for explaining processing by a diamond ball end mill.
  • a predetermined shape is formed by scraping the substrate 100 while rotating the diamond ball end mill 203.
  • the minimum value of the radius of curvature of the cutting edge of the ball end mill 203 is 15 micrometers. Further, in a ball end mill having a cutting edge radius of curvature of 15 micrometers, the rotational speed is 60,000 times per minute, and the feed speed is limited to 10 millimeters per minute.
  • FIG. 8 is a photograph of the cutting edge of the diamond ball end mill 203.
  • the corner R can be controlled within a range of 0.5 micrometers or less as an example.
  • the corner R when the diamond ball end mill is used is 15 micrometers or more which is the minimum value of the curvature radius of the cutting edge.
  • FIG. 9 is a view showing a cross section perpendicular to the longitudinal direction of the linear groove formed by the drawing process.
  • FIG. 9A shows grooves arranged at a constant interval
  • FIG. 9B shows grooves arranged at random intervals.
  • FIG. 10 is a view for explaining the function of the diffraction grating formed by a mold having grooves arranged at a constant interval shown in FIG. If the period of the diffraction grating, that is, the groove interval is d, the diffraction angle is ⁇ , the diffraction order is N, and the wavelength of light is ⁇ , the following relationship is established.
  • the diffraction angle is an angle of the light beam after diffraction with respect to the light beam before diffraction.
  • the light before diffraction is incident perpendicularly to the surface of the substrate before forming the groove.
  • the diffraction angle is positive counterclockwise, and the sign of the diffraction order is matched with the sign of the diffraction angle.
  • Table 1 is a table showing diffraction angles of diffracted light having diffraction orders of ⁇ 1 to ⁇ 3.
  • Table 2 is a table showing diffraction efficiency of diffracted light having diffraction orders of ⁇ 1 to ⁇ 3.
  • FIG. 11 is a diagram showing various modes of grooves having a shape corresponding to the diffraction grating of the second region of the mold having the first region and the second region.
  • the plurality of grooves having a shape corresponding to the diffraction grating shown in FIG. 11B is concentric.
  • the plurality of grooves having a shape corresponding to the diffraction grating in FIG.
  • the plurality of grooves having a shape corresponding to the diffraction grating in FIG.
  • the pattern due to the change in illuminance in the region other than the region 101 ′′ having high illuminance on the surface can be changed.
  • FIG. 12 is a diagram showing a shape corresponding to the microprism array machined in the second region of the substrate.
  • FIG. 12A is a diagram showing the first region where the first groove is formed and the second region where the shape corresponding to the microprism array is machined.
  • the shape corresponding to the microprism array in the second region is configured from a surface that is not parallel to the bottom surface of the groove in the first region.
  • FIG. 12B is an enlarged view of the second region in which the shape corresponding to the microprism array is machined.
  • a plurality of grooves are formed in a first cycle in a first direction by a drawing process, and a plurality of grooves in a second direction different from the first direction are formed by a cutting process.
  • a shape corresponding to a microprism array made of a quadrangular pyramid can be manufactured.
  • a shape corresponding to a microprism array made of a triangular pyramid can be manufactured by forming a plurality of grooves at predetermined intervals in three different directions by drawing on the substrate surface.
  • the substrate may be attached to a rotary table having an angle indexing function, the groove direction may be determined by the angle indexing function, and the groove may be formed by cutting. .
  • FIG. 13 is a diagram showing a shape corresponding to the microlens array machined in the second region of the substrate.
  • FIG. 13 (a) is a diagram showing a first region where the first groove is formed and a second region where the shape corresponding to the microlens array is machined.
  • the shape corresponding to the microlens array in the second region is composed of a surface that is not parallel to the bottom surface of the groove in the first region.
  • FIG. 13B is an enlarged view of the second region in which the shape corresponding to the microlens array is machined.
  • a shape corresponding to the microlens array can be manufactured by performing ultra-precision milling using a diamond ball end mill.
  • the minimum value of the radius of curvature of the cutting edge of the diamond ball end mill is 15 micrometers as described above.
  • a region with high illuminance on the surface is caused by diffusion of light by the microlens array. It is possible to adjust the illuminance in a region other than 101 ′′.
  • FIG. 14 is a diagram showing an AFM (atomic force microscope) image of a mold manufactured by the manufacturing method of the present invention.
  • FIG. 15 is a diagram showing an AFM (atomic force microscope) image of a cross section of a mold having a periodic structure manufactured by the manufacturing method of the present invention.
  • the periodic structure has a period of 2.0 micrometers, and the periodic structure has a depth of 0.76 micrometers.
  • the above cross section is a cross section perpendicular to the repeating direction of the grating having the periodic structure.
  • the width of the bottom surface of the first groove is 7.5 micrometers, which is smaller than the period of the periodic structure.
  • the periodic structure is composed of a surface that is not parallel to the bottom surface of the first groove.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

Provided is a method for producing a mold for an optical element that produces an image with a clear boundary and that is composed of a first portion, which is a substantially flat surface, and a second portion, which is an optical structure for causing a ray of light to diffract, diffuse, or the like. This method for producing a mold for an optical element comprises: a step for forming, by resist patterning and etching, a first groove that has a substantially flat bottom surface having a width of 2 micrometers or more in a first region of a surface of a substrate; and a step for machining a second region that surrounds the first region in the surface of the substrate into a shape constituted of a surface that is not parallel to the bottom surface.

Description

金型の製造方法Mold manufacturing method
　本発明は、金型の製造方法、特に光学素子用金型の製造方法に関する。 The present invention relates to a mold manufacturing method, and more particularly to a method for manufacturing a mold for an optical element.
　光線を透過させる第１の部分と光線を遮蔽する第２の部分とを備えた光学素子であって、該光学素子を通してある面に光線を照射させて該面上に第１の部分の形状に対応する形状を有する、周囲より照度の高い領域を光線によって形成する光学素子が知られている。上記の光学素子の従来の製造方法の一例は、光学素子の第２の部分の表面を金属膜で覆う方法である。この従来の製造方法においては、第２の部分の表面のみに金属膜を成膜するか、表面全体に金属膜を成膜してから第１の部分の金属膜をレーザーなどによって除去する。したがって、上記の製造方法は量産には適していない。 An optical element having a first part that transmits light and a second part that shields the light, and irradiates a surface with light through the optical element to form the first part on the surface. An optical element having a corresponding shape and forming a region with higher illuminance than the surroundings by light rays is known. An example of a conventional method for manufacturing the optical element is a method of covering the surface of the second portion of the optical element with a metal film. In this conventional manufacturing method, a metal film is formed only on the surface of the second portion, or a metal film is formed on the entire surface, and then the first portion of the metal film is removed by a laser or the like. Therefore, the above manufacturing method is not suitable for mass production.
　そこで、量産のために上記の光学素子を金型によって製造することが考えられる。光学素子において、第１の部分はほぼ平坦な面とし、第２の部分は、光線に回折、拡散などを生じさせる光学的構造とすることが考えられる。このような光学素子を通してある面に光線を照射すると、光線は第１の部分をほぼそのまま透過し、第２の部分において回折、拡散などを生じそのまま透過することはないので、該面上に第１の部分の形状に対応する形状を有する周囲より照度の高い領域が形成される。 Therefore, it is conceivable to manufacture the above-described optical element with a mold for mass production. In the optical element, it is conceivable that the first portion has a substantially flat surface, and the second portion has an optical structure that causes diffraction, diffusion, and the like of the light beam. When a surface is irradiated with light through such an optical element, the light passes through the first part almost as it is, and the second part is diffracted, diffused, etc., and does not pass through. A region having a higher illuminance than the periphery having a shape corresponding to the shape of the first portion is formed.
　このような光学素子用の金型は、光学素子の第１の部分に対応するほぼ平坦な領域と光学素子の第２の部分である光学的構造に対応する領域とから構成される。ここで、光学素子の第１の部分に対応するほぼ平坦な領域を金型の第１の領域と呼称し、光学素子の第２の部分である光学的構造に対応する領域を金型の第２の領域と呼称する。光学素子を通過した光線によって形成される周囲より照度の高い領域の境界を鮮明にするために、金型の第１の領域と金型第２の領域との境界には段差があるのが望ましい。また、段差の立ち上がりの隅（コーナー）のコーナーＲはできるだけ小さいのが望ましい。 Such a mold for an optical element includes a substantially flat region corresponding to the first part of the optical element and a region corresponding to the optical structure which is the second part of the optical element. Here, a substantially flat region corresponding to the first portion of the optical element is referred to as a first region of the mold, and a region corresponding to the optical structure which is the second portion of the optical element is referred to as the first portion of the mold. This is referred to as area 2. In order to sharpen the boundary of the region having higher illuminance than the surrounding formed by the light beam that has passed through the optical element, it is desirable that there is a step at the boundary between the first region of the mold and the second region of the mold. . Further, it is desirable that the corner R of the rising edge of the step is as small as possible.
　光学素子用金型のうち、レンズなどの金型は通常ボールエンドミルを使用した機械加工によって製造される。ボールエンドミルによって、たとえば、非球面、自由曲面などに対応する種々の光学面の形状を形成することができる。しかし、ボールエンドミルによって光学素子用の金型を製造する場合には、コーナーＲはボールエンドミルの刃先の曲率半径より小さくすることはできない。ボールエンドミルの刃先の曲率半径の最小値は約１５マイクロメータであるので、コーナーＲの最小値は約１５マイクロメータである。 Among molds for optical elements, molds such as lenses are usually manufactured by machining using a ball end mill. With the ball end mill, various optical surface shapes corresponding to, for example, an aspherical surface and a free-form surface can be formed. However, when a die for an optical element is manufactured by a ball end mill, the corner R cannot be made smaller than the radius of curvature of the edge of the ball end mill. Since the minimum value of the radius of curvature of the edge of the ball end mill is about 15 micrometers, the minimum value of the corner R is about 15 micrometers.
　光学素子用金型のうち、バイナリー回折格子などの金型はレジストパターニング及びエッチングによって製造されることがある。レジストパターニング及びエッチングによれば、例えば、バイナリー回折格子のコーナーＲを１マイクロメータ以下とすることができる。しかし、レジストパターニング及びエッチングによって、非球面、自由曲面などに対応する種々の光学面の形状を形成するのは困難である。 Among optical element molds, molds such as a binary diffraction grating may be manufactured by resist patterning and etching. According to resist patterning and etching, for example, the corner R of the binary diffraction grating can be set to 1 micrometer or less. However, it is difficult to form various optical surface shapes corresponding to aspherical surfaces, free-form surfaces, etc. by resist patterning and etching.
　このように、金型の製造方法において、ボールエンドミルなどを使用する機械加工とレジストパターニング及びエッチングとは別の技術分野に属するものであり両者が組み合わされることはまれであった。 As described above, in the mold manufacturing method, machining using a ball end mill and the like, resist patterning and etching belong to different technical fields, and the two are rarely combined.
　特許文献１は、光線を透過させる部分と光線を遮蔽または拡散させる部分とを有する光学素子を開示している。しかし、特許文献１は、そのような光学素子の製造方法を詳細に開示していない。また、特許文献１の光学素子は、顕微鏡の光量を制御するものであり、光学素子を通過した光線によって面上に形成される周囲より照度の高い領域の境界を鮮明にするという技術的課題とは無関係である。 Patent Document 1 discloses an optical element having a portion that transmits light and a portion that blocks or diffuses light. However, Patent Document 1 does not disclose a method for manufacturing such an optical element in detail. Further, the optical element of Patent Document 1 controls the amount of light of a microscope, and has a technical problem of sharpening the boundary of a region having higher illuminance than the periphery formed on the surface by light rays that have passed through the optical element. Is irrelevant.
　このように、従来、光学素子を通過した光線によって面上に形成される周囲より照度の高い領域の境界を鮮明にすることのできる、ほぼ平坦な面である第１の部分と光線に回折、拡散などを生じさせる光学的構造である第２の部分とから構成される光学素子の金型を高精度かつ高効率で製造する方法は開発されていなかった。 In this way, conventionally, the first part which is a substantially flat surface which can sharpen the boundary of the region with higher illuminance than the surrounding formed on the surface by the light beam that has passed through the optical element, and the light beam are diffracted. A method for manufacturing a mold of an optical element composed of the second portion, which is an optical structure that causes diffusion or the like, with high accuracy and high efficiency has not been developed.
特開2007-033790号公報JP 2007-033790
　したがって、光学素子を通過した光線によって面上に形成される周囲より照度の高い領域の境界を鮮明にすることのできる、ほぼ平坦な面である第１の部分と光線に回折、拡散などを生じさせる光学的構造である第２の部分とから構成される光学素子の金型を高精度かつ高効率で製造する方法に対するニーズがある。本発明の課題は、光学素子を通過した光線によって面上に形成される周囲より照度の高い領域の境界を鮮明にすることのできる、ほぼ平坦な面である第１の部分と光線に回折、拡散などを生じさせる光学的構造である第２の部分とから構成される光学素子の金型を高精度かつ高効率で製造する方法を提供することである。 Therefore, the first part, which is a substantially flat surface, which can sharpen the boundary of the area with higher illuminance formed on the surface by the light beam that has passed through the optical element, causes diffraction, diffusion, etc. There is a need for a method of manufacturing a mold of an optical element composed of a second part that is an optical structure to be manufactured with high accuracy and high efficiency. An object of the present invention is to diffract light into a first portion and a light beam, which is a substantially flat surface, which can sharpen the boundary of a region with higher illuminance than the surroundings formed on the surface by the light beam that has passed through the optical element. An object of the present invention is to provide a method for manufacturing a mold of an optical element composed of a second portion which is an optical structure that causes diffusion or the like with high accuracy and high efficiency.
　本発明による光学素子用の金型の製造方法は、レジストパターニング及びエッチングによって、基板の表面の第１の領域に２マイクロメータ以上の幅のほぼ平坦な底面を有する第１の溝を形成するステップと、該基板の表面の該第１の領域を囲む第２の領域を、該底面と平行ではない面から構成される形状に機械加工するステップとを含む。 The method for manufacturing a mold for an optical element according to the present invention includes forming a first groove having a substantially flat bottom surface having a width of 2 micrometers or more in a first region of a surface of a substrate by resist patterning and etching. And machining a second region surrounding the first region of the surface of the substrate into a shape comprised of a surface that is not parallel to the bottom surface.
　本発明によれば、基板の表面の第１の領域に２マイクロメータ以上の幅のほぼ平坦な底面を有する第１の溝を、レジストパターニング及びエッチングによって形成するので、第１の溝の、ほぼ平坦な底面と側面との境界のコーナーＲを、一例として１マイクロメータ以下にすることができる。したがって、金型から製造される光学素子の、金型の第１の領域に対応する光学素子の第１の部分と金型の第１の領域を囲む金型の第２の領域に対応する光学素子の第２の部分との境界がシャープになる。この結果、該光学素子を通してある面に光線を照射した場合に、金型の第１の領域の形状に対応する鮮明な境界の形状を有する照度の高い領域を該面上に形成することのできる光学素子が得られる。ここで、金型の第１の領域を囲む金型の第２の領域とは、第１の領域の周囲を縁取る領域であって、その金型によって光学素子を製造し、該光学素子を通してある面に光線を照射した場合に、金型の第１の領域の形状に対応する鮮明な境界を有する周囲より照度の高い領域を該面上に形成することができるように形成された領域を意味する。したがって、第１の領域の周囲を縁取る領域以外の領域の形状はどのような形状であってもよい。第２の領域においては、光学素子の所望の機能を実現するために、第１の溝の底面と平行ではない面から構成される形状を機械加工によって高精度かつ高効率で形成することができる。 According to the present invention, the first groove having a substantially flat bottom surface with a width of 2 micrometers or more is formed in the first region of the surface of the substrate by resist patterning and etching. For example, the corner R at the boundary between the flat bottom surface and the side surface can be set to 1 micrometer or less. Therefore, in the optical element manufactured from the mold, the optical corresponding to the first portion of the optical element corresponding to the first area of the mold and the second area of the mold surrounding the first area of the mold. The boundary with the second part of the element becomes sharp. As a result, when light is irradiated onto a certain surface through the optical element, a high illuminance region having a sharp boundary shape corresponding to the shape of the first region of the mold can be formed on the surface. An optical element is obtained. Here, the second region of the mold surrounding the first region of the mold is a region that borders the periphery of the first region, and an optical element is manufactured by the mold, and the optical element is passed through the optical element. A region formed so that when a certain surface is irradiated with light, a region having a bright boundary corresponding to the shape of the first region of the mold and having a higher illuminance than the periphery can be formed on the surface. means. Accordingly, the shape of the region other than the region bordering the periphery of the first region may be any shape. In the second region, in order to realize a desired function of the optical element, a shape constituted by a surface not parallel to the bottom surface of the first groove can be formed with high accuracy and high efficiency by machining. .
　従来、金型の製造において、レジストパターニング及びエッチングならびに機械加工の両方を使用することはまれであった。本発明は、光学素子を通過した光線によって形成される形状の境界を鮮明にすることのできる、ほぼ平坦な面である第１の部分と光線に回折、拡散などを生じさせる光学的構造である第２の部分とから構成される光学素子の金型を高精度かつ高効率で製造する方法を提供するという技術的課題を解決するために、レジストパターニング及びエッチングならびに機械加工の両方を適切に組み合わせた点を特徴とする。 Conventionally, it has been rare to use both resist patterning and etching and machining in the manufacture of molds. The present invention is an optical structure capable of sharpening the shape boundary formed by the light beam that has passed through the optical element and causing the light beam to be diffracted, diffused, etc., which is a substantially flat surface. In order to solve the technical problem of providing a method of manufacturing a mold of an optical element composed of the second part with high accuracy and high efficiency, both resist patterning and etching and machining are appropriately combined. It is characterized by points.
　本発明の第１の実施形態による金型の製造方法においては、該第１の溝の深さが３０マイクロメータ以下であり、該第２の領域の該形状の深さが２０マイクロメータ以下である。 In the mold manufacturing method according to the first embodiment of the present invention, the depth of the first groove is 30 micrometers or less, and the depth of the shape of the second region is 20 micrometers or less. is there.
　本実施形態による金型の製造方法において、第１の領域における第１の溝及び第２の領域における形状の加工前の基板の表面からの深さは３０マイクロメータ以下である。したがって、厚さの小さなコンパクトな光学素子が得られる。 In the mold manufacturing method according to the present embodiment, the depth from the surface of the substrate before processing the first groove in the first region and the shape in the second region is 30 micrometers or less. Therefore, a compact optical element having a small thickness can be obtained.
　本発明の第２の実施形態による金型の製造方法において、該第２の領域の該形状が周期的な構造を含み、該周期的な構造の周期が該第１の溝の底面の幅よりも小さい。 In the mold manufacturing method according to the second embodiment of the present invention, the shape of the second region includes a periodic structure, and the period of the periodic structure is greater than the width of the bottom surface of the first groove. Is also small.
　本実施形態による金型によって製造された光学素子の、第２の領域に対応する部分は、周期的な構造を含むので光線の回折、拡散などを生じさせることができる。 The portion corresponding to the second region of the optical element manufactured by the mold according to the present embodiment includes a periodic structure, and therefore can cause diffraction and diffusion of light rays.
　本発明の第３の実施形態による金型の製造方法において、該第２の領域の該形状が、長手方向がほぼ同じ方向となるように配列された複数の第２の溝であり、該複数の第２の溝の長手方向に垂直な断面が周期的な構造を示す
　本実施形態による金型によって製造された光学素子の、第２の領域に対応する部分の断面は周期的な構造を示すので光線の回折、拡散などを生じさせることができる。 In the mold manufacturing method according to the third embodiment of the present invention, the shape of the second region is a plurality of second grooves arranged so that the longitudinal directions thereof are substantially the same direction, The cross section perpendicular to the longitudinal direction of the second groove of the optical device shows a periodic structure. The cross section of the portion corresponding to the second region of the optical element manufactured by the mold according to the present embodiment shows the periodic structure. Therefore, it is possible to cause diffraction and diffusion of light rays.
　本発明の第４の実施形態による金型の製造方法においては、該第２の領域の該形状が該光学素子の回折格子に対応する。 In the mold manufacturing method according to the fourth embodiment of the present invention, the shape of the second region corresponds to the diffraction grating of the optical element.
　本実施形態による金型の製造方法によって、金型の第２の領域に対応する第２の部分が回折格子からなる光学素子が得られる。光学素子を通してある面を照射した場合に、該面における金型の第１の領域に対応する、照度の高い領域以外の領域の照度を回折格子によって調整することができることができる。 By the mold manufacturing method according to the present embodiment, an optical element in which the second portion corresponding to the second region of the mold is a diffraction grating is obtained. When a certain surface is irradiated through the optical element, the illuminance of a region other than the high illuminance region corresponding to the first region of the mold on the surface can be adjusted by the diffraction grating.
　本発明の第５の実施形態による金型の製造方法においては、該第２の領域の該形状が該光学素子のマイクロプリズムアレイに対応する。 In the mold manufacturing method according to the fifth embodiment of the present invention, the shape of the second region corresponds to the microprism array of the optical element.
　本実施形態による金型の製造方法によって、第２の領域に対応する領域にマイクロプリズムアレイを備えた光学素子が得られる。光学素子を通してある面を照射した場合に、該面における第１の領域に対応する照度の高い領域以外の領域の照度をマイクロプリズムアレイによって調整することができる。 The optical element having the microprism array in the region corresponding to the second region can be obtained by the mold manufacturing method according to the present embodiment. When a certain surface is irradiated through the optical element, the illuminance in a region other than the high illuminance region corresponding to the first region on the surface can be adjusted by the microprism array.
　本発明の第６の実施形態による金型の製造方法においては、該第２の領域の該形状が該光学素子のマイクロレンズアレイに対応する。 In the mold manufacturing method according to the sixth embodiment of the present invention, the shape of the second region corresponds to the microlens array of the optical element.
　本実施形態による金型の製造方法によって、第２の領域に対応する領域にマイクロレンズアレイを備えた光学素子が得られる。光学素子を通してある射面を照射した場合に、該面における第１の領域に対応する照度の高い領域以外の領域の照度をマイクロレンズアレイによって調整することができる。 The optical element having the microlens array in the region corresponding to the second region can be obtained by the mold manufacturing method according to the present embodiment. When a certain incident surface is irradiated through the optical element, the illuminance in a region other than the high illuminance region corresponding to the first region on the surface can be adjusted by the microlens array.
　本発明の第７の実施形態による金型の製造方法においては、該第２の領域の該形状を引き切り加工によって形成する。 In the mold manufacturing method according to the seventh embodiment of the present invention, the shape of the second region is formed by drawing.
　本実施形態による金型の製造方法においては、第２の領域における回折格子などの形状を引き切り加工によって形成する。したがって、回折格子などの形状を高精度かつ高効率で形成することができる。 In the mold manufacturing method according to the present embodiment, the shape of the diffraction grating or the like in the second region is formed by drawing. Therefore, a shape such as a diffraction grating can be formed with high accuracy and high efficiency.
　本発明の第８の実施形態による金型の製造方法においては、該第２の領域の該形状を、ダイヤモンド切削工具を使用して形成する。 In the mold manufacturing method according to the eighth embodiment of the present invention, the shape of the second region is formed using a diamond cutting tool.
　本発明の第９の実施形態による金型の製造方法においては、１マイクロメータ以下のコーナーＲで該第１の溝及び該形状を形成する。 In the mold manufacturing method according to the ninth embodiment of the present invention, the first groove and the shape are formed at a corner R of 1 micrometer or less.
　本実施形態による金型のコーナーＲは１マイクロメータ以下であるので、金型から製造される光学素子の、第１の領域に対応する領域と第１の領域を囲む第２の領域に対応する領域との境界がシャープになる。この結果、光線を照射した場合に、第１の領域の形状に対応する照度の高い領域であって、鮮明な境界を有する領域を形成することのできる光学素子が得られる。 Since the corner R of the mold according to the present embodiment is 1 micrometer or less, the optical element manufactured from the mold corresponds to a region corresponding to the first region and a second region surrounding the first region. The boundary with the area becomes sharp. As a result, it is possible to obtain an optical element capable of forming a region having a high illuminance corresponding to the shape of the first region and having a sharp boundary when irradiated with a light beam.
本発明の一実施形態の、光学素子用の金型の製造方法を示す流れ図である。It is a flowchart which shows the manufacturing method of the metal mold | die for optical elements of one Embodiment of this invention. 上記の光学素子用の金型の製造方法を説明するための図である。It is a figure for demonstrating the manufacturing method of the metal mold | die for said optical elements. 機械加工後の基板の断面を示す図である。It is a figure which shows the cross section of the board | substrate after machining. 図３に示すような断面を有する金型によって成形された光学素子の一例を示す図である。It is a figure which shows an example of the optical element shape | molded by the metal mold | die which has a cross section as shown in FIG. 矩形状のダイヤモンド工具を使用した引き切り加工を説明するための図である。It is a figure for demonstrating the drawing process using a rectangular diamond tool. 矩形状のダイヤモンド工具の刃先の写真である。It is a photograph of the cutting edge of a rectangular diamond tool. ダイヤモンド・ボールエンドミルによる加工を説明するための図である。It is a figure for demonstrating the process by a diamond ball end mill. ダイヤモンド・ボールエンドミルの刃先の写真である。It is a photograph of the cutting edge of a diamond ball end mill. 引き切り加工によって形成された直線状の溝の長手方向に垂直な断面を示す図である。It is a figure which shows the cross section perpendicular | vertical to the longitudinal direction of the linear groove | channel formed by the drawing process. 図９（ａ）に示す一定の間隔で配置された溝を有する金型によって成形された回折格子の機能を説明するための図である。It is a figure for demonstrating the function of the diffraction grating shape | molded by the metal mold | die which has the groove | channel arrange | positioned at the fixed space | interval shown to Fig.9 (a). 第１の領域及び第２の領域を備えた金型の、第２の領域の回折格子に対応する形状の溝の種々の態様を示す図である。It is a figure which shows the various aspects of the groove | channel of the shape corresponding to the diffraction grating of a 2nd area | region of the metal mold | die provided with the 1st area | region and the 2nd area | region. 、基板の第２の領域に機械加工されたマイクロプリズムアレイに対応する形状を示す図である。FIG. 4 is a diagram illustrating a shape corresponding to a microprism array machined in a second region of a substrate. 基板の第２の領域に機械加工されたマイクロレンズアレイに対応する形状を示す図である。It is a figure which shows the shape corresponding to the micro lens array machined to the 2nd area | region of a board | substrate. 本発明の製造方法によって製造された金型のＡＦＭ（原子間力顕微鏡）像を示す図である。It is a figure which shows the AFM (atomic force microscope) image of the metal mold | die manufactured by the manufacturing method of this invention. 本発明の製造方法によって製造された周期構造を有する金型の断面のＡＦＭ（原子間力顕微鏡）像を示す図である。It is a figure which shows the AFM (atomic force microscope) image of the cross section of the metal mold | die which has the periodic structure manufactured by the manufacturing method of this invention.
　図１は、本発明の一実施形態の、光学素子用の金型の製造方法を示す流れ図である。 FIG. 1 is a flowchart showing a method for manufacturing a mold for optical elements according to an embodiment of the present invention.
　図２は、上記の光学素子用の金型の製造方法を説明するための図である。 FIG. 2 is a diagram for explaining a method of manufacturing the mold for the optical element described above.
　図１のステップＳ１０１０において基板を洗浄する。基板の材料は、一例として、無電解ニッケルリン鍍金であってもよい。 In step S1010 of FIG. 1, the substrate is cleaned. As an example, the substrate material may be an electroless nickel phosphor plating.
　図２（ａ）は、洗浄後の基板の断面を示す図である。 FIG. 2A is a view showing a cross section of the substrate after cleaning.
　図２のステップＳ１０２０において、基板の表面に第１の溝を形成するためのレジストパターニングを実施する。具体的には、基板の表面の、第１の領域以外の第２の領域をレジストで覆う。 In step S1020 of FIG. 2, resist patterning for forming the first groove on the surface of the substrate is performed. Specifically, the second region other than the first region on the surface of the substrate is covered with a resist.
　図２（ｂ）は、基板の表面の、第１の領域以外の第２の領域がレジストで覆われた基板の断面を示す図である。 FIG. 2B is a diagram showing a cross section of the substrate in which a second region other than the first region on the surface of the substrate is covered with a resist.
　図２のステップＳ１０３０において、エッチングを実施しての第１の領域に第１の溝を形成する。エッチングは、一例として、イオンビームエッチングであってもよい。 In step S1030 of FIG. 2, etching is performed to form a first groove in the first region. As an example, the etching may be ion beam etching.
　図２（ｃ）は、エッチング後の基板の断面を示す図である。基板の表面の第１の領域に第１の溝が形成されている。 FIG. 2C is a diagram showing a cross section of the substrate after etching. A first groove is formed in a first region on the surface of the substrate.
　図２のステップＳ１０４０において、レジストを除去する。 In step S1040 of FIG. 2, the resist is removed.
　図２（ｄ）は、レジストを除去した後の基板の断面を示す図である。基板の表面の第１の領域には第１の溝が形成されている。第１の溝の底面はほぼ平坦であり、第１の溝の底面の幅は２マイクロメータ以上である。第１の溝の底面は、加工前の基板の表面とほぼ平行である。また、第１の溝の加工前の基板の表面からの深さは１マイクロメータ以上、３０マイクロメータ以下である。 FIG. 2D is a view showing a cross section of the substrate after the resist is removed. A first groove is formed in the first region on the surface of the substrate. The bottom surface of the first groove is substantially flat, and the width of the bottom surface of the first groove is 2 micrometers or more. The bottom surface of the first groove is substantially parallel to the surface of the substrate before processing. Moreover, the depth from the surface of the board | substrate before the process of a 1st groove | channel is 1 micrometer or more and 30 micrometers or less.
　図２のステップＳ１０５０において、第１の領域以外の第２の領域を機械加工することによって第１の溝の底面と平行ではない面から構成される形状を形成する。第２の領域の形状の、加工前の基板の表面からの深さは０．５マイクロメータ以上、２０マイクロメータ以下である。 In step S1050 of FIG. 2, the second region other than the first region is machined to form a shape composed of a surface that is not parallel to the bottom surface of the first groove. The depth of the shape of the second region from the surface of the substrate before processing is not less than 0.5 micrometers and not more than 20 micrometers.
　このように、第１の溝及び第２の領域の形状の、加工前の基板の表面からの深さは３０マイクロメータ以下である。 Thus, the depth of the shape of the first groove and the second region from the surface of the substrate before processing is 30 micrometers or less.
　図２（ｅ）は、機械加工後の基板、すなわち金型の断面を示す図である。第２の領域には機械加工によって周期構造が形成されている。なお、機械加工については後で詳細に説明する。上記の断面は上記の周期構造の長手方向及び加工前の基板の表面に垂直である。 FIG. 2 (e) is a diagram showing a cross-section of a substrate after machining, that is, a mold. A periodic structure is formed in the second region by machining. The machining will be described later in detail. The cross section is perpendicular to the longitudinal direction of the periodic structure and the surface of the substrate before processing.
　金型を製造する際に、上述のように、レジストパターニング、エッチング、機械加工の順に実施すべきである。機械加工を最初に実施すると、レジストパターニング及びエッチングによってほぼ平坦な底面を有する溝を形成することができない。レジストパターニングの後、エッチングの前にレジストに機械加工を実施すると、レジストに機械加工によって形成された形状がエッチングによって変形されるなどの問題が生じ、金型の形状の精度が劣化する。 When manufacturing the mold, as described above, resist patterning, etching, and machining should be performed in this order. When machining is performed first, a groove having a substantially flat bottom surface cannot be formed by resist patterning and etching. If the resist is machined after the resist patterning and before the etching, there arises a problem that the shape formed by machining on the resist is deformed by the etching, and the accuracy of the shape of the mold is deteriorated.
　上記の金型を使用して、たとえば、射出成形によって光学素子を大量に製造することができる。 Using the above mold, it is possible to manufacture a large number of optical elements by, for example, injection molding.
　図３は、図２（ｅ）と同様に、機械加工後の基板の、周期構造の長手方向及び加工前の基板の表面に垂直な断面を示す図である。基板１００の第１の領域１０１には底面がほぼ平坦な溝が形成され、第１の領域１０１以外の第２の領域１０３には周期構造が形成されている。周期構造は、一例として、回折格子に対応する。また、周期構造は、第１の領域１０１の溝の底面と平行ではない面から構成されている。 FIG. 3 is a diagram showing a cross section perpendicular to the longitudinal direction of the periodic structure and the surface of the substrate before processing of the substrate after machining, as in FIG. 2 (e). A groove having a substantially flat bottom surface is formed in the first region 101 of the substrate 100, and a periodic structure is formed in the second region 103 other than the first region 101. The periodic structure corresponds to a diffraction grating as an example. Further, the periodic structure is configured from a surface that is not parallel to the bottom surface of the groove of the first region 101.
　図４は、図３に示すような断面を有する金型によって成形された光学素子の一例を示す図である。第１の領域１０１に対応する光学素子１００’の第１の部分１０１’は平坦な面である。第２の領域１０３に対応する光学素子１００’ の第２の部分１０３’は回折格子である。光学素子１００’を通してある面に光を照射すると、第１の部分１０１’は光線を、回折を生じさせることなく透過させ、回折格子である第２の部分１０３’は光を回折させるので、該面上において第１の部分１０１’の形状に対応する形状を有する領域１０１”の照度はその周囲よりも高くなる。したがって、該面上において、第１の部分１０１’の形状に対応する形状の領域１０１”が識別可能となる。 FIG. 4 is a view showing an example of an optical element formed by a mold having a cross section as shown in FIG. The first portion 101 'of the optical element 100' corresponding to the first region 101 is a flat surface. The second portion 103 ′ of the optical element 100 ′ corresponding to the second region 103 is a diffraction grating. When light is irradiated onto a surface through the optical element 100 ′, the first portion 101 ′ transmits the light beam without causing diffraction, and the second portion 103 ′, which is a diffraction grating, diffracts the light. The illuminance of the region 101 ″ having a shape corresponding to the shape of the first portion 101 ′ on the surface is higher than the surrounding area. Therefore, the shape of the region 101 ″ corresponding to the shape of the first portion 101 ′ on the surface is higher. The area 101 ″ can be identified.
　つぎに、第２の領域１０３における機械加工について説明する。 Next, machining in the second region 103 will be described.
　図５は、矩形状のダイヤモンド工具を使用した引き切り加工を説明するための図である。図５において、矩形状のダイヤモンド工具２０１を直線状に移動させながら基板１００を削ることによって刃先の形状と同じ形状を断面とする溝が形成される。このような加工方法を引き切り加工と呼称する。一例として、断面がＶ字型の刃の開き角度が５度の場合には、表面における溝の幅を１０マイクロメータとすると溝の深さは約１マイクロメータとなる。 FIG. 5 is a diagram for explaining a drawing process using a rectangular diamond tool. In FIG. 5, a groove having a cross section of the same shape as the shape of the blade edge is formed by cutting the substrate 100 while moving a rectangular diamond tool 201 linearly. Such a processing method is referred to as a drawing process. As an example, when the opening angle of a V-shaped blade is 5 degrees, the groove depth is about 1 micrometer when the groove width on the surface is 10 micrometers.
　図６は、矩形状のダイヤモンド工具２０１の刃先の写真である。 FIG. 6 is a photograph of the cutting edge of the rectangular diamond tool 201.
　図７は、ダイヤモンド・ボールエンドミルによる加工を説明するための図である。図７において、ダイヤモンド・ボールエンドミル２０３を回転させながら基板１００を削ることによって所定の形状が形成される。ボールエンドミル２０３の刃先の曲率半径の最小値は１５マイクロメータである。また、刃先の曲率半径が１５マイクロメータのボールエンドミルにおいて、回転速度を６０，０００回毎分として、送り速度は１０ミリメータ毎分に制限される。 FIG. 7 is a diagram for explaining processing by a diamond ball end mill. In FIG. 7, a predetermined shape is formed by scraping the substrate 100 while rotating the diamond ball end mill 203. The minimum value of the radius of curvature of the cutting edge of the ball end mill 203 is 15 micrometers. Further, in a ball end mill having a cutting edge radius of curvature of 15 micrometers, the rotational speed is 60,000 times per minute, and the feed speed is limited to 10 millimeters per minute.
　図８は、ダイヤモンド・ボールエンドミル２０３の刃先の写真である。 FIG. 8 is a photograph of the cutting edge of the diamond ball end mill 203.
　引き切り加工とボールエンドミルによる加工とを比較する。第一に、ボールエンドミルの刃先の曲率半径の最小値は約１５マイクロメータであるので、溝の幅が３０マイクロメータより小さな場合にはボールエンドミルによる加工で溝を形成することができない。したがって、溝の幅が３０マイクロメータより小さな場合には、溝は引き切り加工で形成される。第二に、加工効率の観点からは、送り速度の速い引き切り加工が有利である。第三に、矩形状のダイヤモンド工具を使用した引き切り加工によれば、コーナーＲを、一例として、０．５マイクロメータ以下の範囲で制御することができる。他方、ダイヤモンド・ボールエンドミルを使用した場合のコーナーＲは、刃先の曲率半径の最小値である１５マイクロメータ以上となる。このように、ボールエンドミルでは形成することのできない１５マイクロメータよりも小さいコーナーＲのＵ字状の溝を引き切り加工で形成することができる。 引 き Compare the drawing process with the ball end mill. First, since the minimum value of the radius of curvature of the edge of the ball end mill is about 15 micrometers, when the width of the groove is smaller than 30 micrometers, the groove cannot be formed by processing with the ball end mill. Therefore, when the groove width is smaller than 30 micrometers, the groove is formed by drawing. Secondly, from the viewpoint of processing efficiency, a drawing process with a high feed rate is advantageous. Third, according to the drawing process using a rectangular diamond tool, the corner R can be controlled within a range of 0.5 micrometers or less as an example. On the other hand, the corner R when the diamond ball end mill is used is 15 micrometers or more which is the minimum value of the curvature radius of the cutting edge. Thus, a U-shaped groove having a corner R smaller than 15 micrometers, which cannot be formed by a ball end mill, can be formed by drawing.
　図９は、引き切り加工によって形成された直線状の溝の長手方向に垂直な断面を示す図である。図９（ａ）は一定の間隔で配置された溝を示し、図９（ｂ）はランダムな間隔で配置された溝を示す。 FIG. 9 is a view showing a cross section perpendicular to the longitudinal direction of the linear groove formed by the drawing process. FIG. 9A shows grooves arranged at a constant interval, and FIG. 9B shows grooves arranged at random intervals.
　図１０は、図９（ａ）に示す一定の間隔で配置された溝を有する金型によって成形された回折格子の機能を説明するための図である。回折格子の周期、すなわち溝の間隔をｄ、回折角度をθ、回折次数をＮ、光の波長をλで表すと、以下の関係が成立する。回折角度とは、回折後の光線の、回折前の光線に対する角度である。図１０において、回折前の光線は、溝を形成する前の基板の面に垂直に入射する。また、図１０において、回折角度は反時計回りを正とし、回折次数の符号は回折角度の符号に合わせる。
Figure JPOXMLDOC01-appb-M000001
 FIG. 10 is a view for explaining the function of the diffraction grating formed by a mold having grooves arranged at a constant interval shown in FIG. If the period of the diffraction grating, that is, the groove interval is d, the diffraction angle is θ, the diffraction order is N, and the wavelength of light is λ, the following relationship is established. The diffraction angle is an angle of the light beam after diffraction with respect to the light beam before diffraction. In FIG. 10, the light before diffraction is incident perpendicularly to the surface of the substrate before forming the groove. In FIG. 10, the diffraction angle is positive counterclockwise, and the sign of the diffraction order is matched with the sign of the diffraction angle.
Figure JPOXMLDOC01-appb-M000001
　表１は、回折次数が±１から±３の回折光の回折角度を示す表である。光の波長λ及び回折格子の周期ｄは以下のとおりである。
　λ=546nm, d=2000nm Table 1 is a table showing diffraction angles of diffracted light having diffraction orders of ± 1 to ± 3. The wavelength λ of light and the period d of the diffraction grating are as follows.
λ = 546nm, d = 2000nm
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２は、回折次数が±１から±３の回折光の回折効率を示す表である。
Figure JPOXMLDOC01-appb-T000003
 Table 2 is a table showing diffraction efficiency of diffracted light having diffraction orders of ± 1 to ± 3.
Figure JPOXMLDOC01-appb-T000003
　このように回折格子に入射した光線のほとんどは、所定の回折角度で回折し直進しないので、図４に示すように、光学素子を通してある面を照射した場合に、光学素子の部分１０１’を通過した光線によって該面上に周囲よりも照度の高い領域１０１”が形成される。 Since most of the light rays incident on the diffraction grating in this manner are diffracted at a predetermined diffraction angle and do not go straight, as shown in FIG. 4, when a certain surface is irradiated through the optical element, it passes through the optical element portion 101 ′. A region 101 ″ having a higher illuminance than the surroundings is formed on the surface by the light rays.
　図１１は、第１の領域及び第２の領域を備えた金型の、第２の領域の回折格子に対応する形状の溝の種々の態様を示す図である。 FIG. 11 is a diagram showing various modes of grooves having a shape corresponding to the diffraction grating of the second region of the mold having the first region and the second region.
　図１１（ａ）の回折格子に対応する形状の複数の溝は直線状である。 A plurality of grooves having a shape corresponding to the diffraction grating of FIG.
　図１１（ｂ）の回折格子に対応する形状の複数の溝は同心円状である。 The plurality of grooves having a shape corresponding to the diffraction grating shown in FIG. 11B is concentric.
　図１１（ｃ）の回折格子に対応する形状の複数の溝は放射線状である。 The plurality of grooves having a shape corresponding to the diffraction grating in FIG.
　図１１（ｄ）の回折格子に対応する形状の複数の溝は緩やかな曲線状である。 The plurality of grooves having a shape corresponding to the diffraction grating in FIG.
　回折格子の溝の態様を変えることにより、光学素子を通してある面を照射した場合に、該面における照度の高い領域１０１”以外の領域の照度の変化による模様を変えることができる。 By changing the shape of the grooves of the diffraction grating, when a certain surface is irradiated through the optical element, the pattern due to the change in illuminance in the region other than the region 101 ″ having high illuminance on the surface can be changed.
　図１２は、基板の第２の領域に機械加工されたマイクロプリズムアレイに対応する形状を示す図である。 FIG. 12 is a diagram showing a shape corresponding to the microprism array machined in the second region of the substrate.
　図１２（ａ）は、第１の溝が形成された第１の領域及びマイクロプリズムアレイに対応する形状が機械加工された第２の領域を示す図である。第２の領域のマイクロプリズムアレイに対応する形状は、第１の領域の溝の底面と平行ではない面から構成されている。 FIG. 12A is a diagram showing the first region where the first groove is formed and the second region where the shape corresponding to the microprism array is machined. The shape corresponding to the microprism array in the second region is configured from a surface that is not parallel to the bottom surface of the groove in the first region.
　図１２（ｂ）は、マイクロプリズムアレイに対応する形状が機械加工された第２の領域の拡大図である。 FIG. 12B is an enlarged view of the second region in which the shape corresponding to the microprism array is machined.
　基板の第２の領域において、引き切り加工によって第１の方向に所定の周期で複数の溝形成し、引き切り加工によって第１の方向と異なる第２の方向に該所定の周期で複数の溝を形成することによって四角錐からなるマイクロプリズムアレイに対応する形状を製造することができる。また、基板面において、引き切り加工によって互いに異なる三方向に所定の周期で複数の溝を形成することによって三角錐からなるマイクロプリズムアレイに対応する形状を製造することができる。基板面に種々の方向の溝を形成するために、一例として、角度割り出し機能を備えた回転テーブルに基板を取り付けて角度割り出し機能によって溝の方向を定め引き切り加工によって溝を形成してもよい。 In the second region of the substrate, a plurality of grooves are formed in a first cycle in a first direction by a drawing process, and a plurality of grooves in a second direction different from the first direction are formed by a cutting process. A shape corresponding to a microprism array made of a quadrangular pyramid can be manufactured. In addition, a shape corresponding to a microprism array made of a triangular pyramid can be manufactured by forming a plurality of grooves at predetermined intervals in three different directions by drawing on the substrate surface. In order to form grooves in various directions on the substrate surface, as an example, the substrate may be attached to a rotary table having an angle indexing function, the groove direction may be determined by the angle indexing function, and the groove may be formed by cutting. .
　上記のマイクロプリズムアレイに対応する形状を備えた金型によって製造されたマイクロプリズムアレイを備えた光学素子を通してある面を照射した場合に、マイクロプリズムアレイによる光の拡散によって該面における照度の高い領域１０１”以外の領域の照度を調整することができる。 When a surface is irradiated through an optical element including a microprism array manufactured by a mold having a shape corresponding to the microprism array, a region with high illuminance on the surface due to diffusion of light by the microprism array It is possible to adjust the illuminance in a region other than 101 ″.
　図１３は、基板の第２の領域に機械加工されたマイクロレンズアレイに対応する形状を示す図である。 FIG. 13 is a diagram showing a shape corresponding to the microlens array machined in the second region of the substrate.
　図１３（ａ）は、第１の溝が形成された第１の領域及びマイクロレンズアレイに対応する形状が機械加工された第２の領域を示す図である。第２の領域のマイクロレンズアレイに対応する形状は、第１の領域の溝の底面と平行ではない面から構成されている。 FIG. 13 (a) is a diagram showing a first region where the first groove is formed and a second region where the shape corresponding to the microlens array is machined. The shape corresponding to the microlens array in the second region is composed of a surface that is not parallel to the bottom surface of the groove in the first region.
　図１３（ｂ）は、マイクロレンズアレイに対応する形状が機械加工された第２の領域の拡大図である。 FIG. 13B is an enlarged view of the second region in which the shape corresponding to the microlens array is machined.
　基板の第２の領域において、ダイヤモンド・ボールエンドミルを使用して超精密ミリング加工を実施することによりマイクロレンズアレイに対応する形状を製造することができる。ダイヤモンド・ボールエンドミルの刃先の曲率半径の最小値は上述のように１５マイクロメータである。 In the second region of the substrate, a shape corresponding to the microlens array can be manufactured by performing ultra-precision milling using a diamond ball end mill. The minimum value of the radius of curvature of the cutting edge of the diamond ball end mill is 15 micrometers as described above.
　上記のマイクロレンズアレイに対応する形状を備えた金型によって製造されたマイクロレンズアレイを備えた光学素子を通してある面を照射した場合に、マイクロレンズアレイによる光の拡散によって該面における照度の高い領域１０１”以外の領域の照度を調整することができる。 When a surface is irradiated through an optical element including a microlens array manufactured by a mold having a shape corresponding to the microlens array, a region with high illuminance on the surface is caused by diffusion of light by the microlens array. It is possible to adjust the illuminance in a region other than 101 ″.
　図１４は本発明の製造方法によって製造された金型のＡＦＭ（原子間力顕微鏡）像を示す図である。 FIG. 14 is a diagram showing an AFM (atomic force microscope) image of a mold manufactured by the manufacturing method of the present invention.
　図１５は本発明の製造方法によって製造された周期構造を有する金型の断面のＡＦＭ（原子間力顕微鏡）像を示す図である。周期構造の周期は２．０マイクロメータ、周期構造の深さは０．７６マイクロメータである。上記の断面は、周期構造である格子の繰り返し方向に垂直な断面である。第１の溝の底面の幅は、７．５マイクロメータであり、上記の周期構造の周期よりも小さい。また、周期構造は、第１の溝の底面と平行ではない面から構成されている。 FIG. 15 is a diagram showing an AFM (atomic force microscope) image of a cross section of a mold having a periodic structure manufactured by the manufacturing method of the present invention. The periodic structure has a period of 2.0 micrometers, and the periodic structure has a depth of 0.76 micrometers. The above cross section is a cross section perpendicular to the repeating direction of the grating having the periodic structure. The width of the bottom surface of the first groove is 7.5 micrometers, which is smaller than the period of the periodic structure. In addition, the periodic structure is composed of a surface that is not parallel to the bottom surface of the first groove.

Claims (10)

  1. 　光学素子用の金型の製造方法であって、
    　レジストパターニング及びエッチングによって、基板の表面の第１の領域に２マイクロメータ以上の幅のほぼ平坦な底面を有する第１の溝を形成するステップと、
    　該基板の表面の該第１の領域を囲む第２の領域を、該底面と平行ではない面から構成される形状に機械加工するステップとを含む金型の製造方法。     A method of manufacturing a mold for an optical element,
    Forming a first groove having a substantially flat bottom surface with a width of 2 micrometers or more in a first region of the surface of the substrate by resist patterning and etching;
    Machining a second region surrounding the first region of the surface of the substrate into a shape composed of a surface that is not parallel to the bottom surface.
  2. 　該第１の溝の深さが３０マイクロメータ以下であり、該第２の領域の該形状の深さが２０マイクロメータ以下である請求項１に記載の金型の製造方法。 The method for manufacturing a mold according to claim 1, wherein the depth of the first groove is 30 micrometers or less, and the depth of the shape of the second region is 20 micrometers or less.
  3. 　該第２の領域の該形状が周期的な構造を含み、該周期的な構造の周期が該第１の溝の底面の幅よりも小さい請求項１または２に記載の金型の製造方法。 The method for manufacturing a mold according to claim 1 or 2, wherein the shape of the second region includes a periodic structure, and a period of the periodic structure is smaller than a width of a bottom surface of the first groove.
  4. 　該第２の領域の該形状が、長手方向がほぼ同じ方向となるように配列された複数の第２の溝であり、該複数の第２の溝の長手方向に垂直な断面が周期的な構造を示す請求項３に記載の金型の製造方法。 The shape of the second region is a plurality of second grooves arranged so that the longitudinal direction is substantially the same direction, and a cross section perpendicular to the longitudinal direction of the plurality of second grooves is periodic. The manufacturing method of the metal mold | die of Claim 3 which shows a structure.
  5. 　該第２の領域の該形状が該光学素子の回折格子に対応する請求項１から４のいずれかに記載の金型の製造方法。 The method for manufacturing a mold according to any one of claims 1 to 4, wherein the shape of the second region corresponds to a diffraction grating of the optical element.
  6. 　該第２の領域の該形状が該光学素子のマイクロプリズムアレイに対応する請求項１から３のいずれかに記載の金型の製造方法。 The method for manufacturing a mold according to any one of claims 1 to 3, wherein the shape of the second region corresponds to a microprism array of the optical element.
  7. 　該第２の領域の該形状が該光学素子のマイクロレンズアレイに対応する請求項１から３のいずれかに記載の金型の製造方法。 The method for manufacturing a mold according to any one of claims 1 to 3, wherein the shape of the second region corresponds to a microlens array of the optical element.
  8. 　該第２の領域の該形状を引き切り加工によって形成する請求項１から６のいずれかに記載の金型の製造方法。 The method for manufacturing a mold according to any one of claims 1 to 6, wherein the shape of the second region is formed by a drawing process.
  9. 　該第２の領域の該形状を、ダイヤモンド切削工具を使用して形成する請求項１から８のいずれかに記載の金型の製造方法。 The method of manufacturing a mold according to any one of claims 1 to 8, wherein the shape of the second region is formed using a diamond cutting tool.
  10. 　１マイクロメータ以下のコーナーＲで該第１の溝及び該第２の領域の該形状を形成する請求項１から６のいずれかに記載の金型の製造方法。 The method for manufacturing a mold according to any one of claims 1 to 6, wherein the shape of the first groove and the second region is formed at a corner R of 1 micrometer or less.
PCT/JP2019/005312 2018-02-21 2019-02-14 Method for producing mold WO2019163630A1 (en)

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