JP2013256015A - Surface shape forming method, mold for forming microstructure, and method of manufacturing optical element - Google Patents

Abstract

In a surface shape forming method, a fine structure having a plurality of uneven shapes can be accurately formed on a curved work surface.
A method of forming a surface shape for forming an antireflection portion, comprising a sheet-like elastic body, wherein the antireflection portion is reversed and rearranged, and a shape compressed in the in-plane direction of a surface 5c is provided. A sheet-shaped mold member disposing step of disposing the formed film mold 5 in the opening 6a of the mold holding member 6, and a sheet-shaped mold member deforming step of stretching the film mold 5 in accordance with the curved shape of the convex lens surface 1a; A sheet-shaped mold member moving step of moving the molding surface portion 5A to a position close to the convex lens surface 1a by arranging the UV curable resin, and a sheet-shaped mold member pressing step of pressing the film mold 5 against the convex lens surface 1a; A curing step of curing the UV curable resin, and a releasing step of separating the film mold 5 from the convex lens surface 1a after curing.
[Selection] Figure 2

Description

  The present invention relates to a surface shape molding method, a microstructure forming mold, and a method for manufacturing an optical element.

2. Description of the Related Art Conventionally, for example, a lens surface of an imaging lens such as a camera is often provided with an antireflection film using a multilayer thin film in order to prevent reflection of unnecessary light such as ghosts and flares.
In recent years, as an antireflection structure that does not depend on such a multilayer thin film, an antireflection structure in which a fine structure with units such as a triangular pyramid or a quadrangular pyramid is formed on the lens surface so that a refractive index change occurs in the vicinity of the lens surface. Structures have been proposed. Moreover, according to such a fine structure, it is also possible to constitute a light scattering structure.
On the other hand, nanoimprinting is known as a method for forming a surface shape for forming a fine structure composed of fine irregularities on the surface of a workpiece. In nanoimprinting, it is common to transfer to a flat surface using a flat mold. For example, a fine structure cannot be formed on an optical element having a curved surface to be formed, such as a lens surface. There wasn't.
For this reason, in order to form a fine concavo-convex shape on the curved surface, it is necessary to form a shape in which such a concavo-convex shape is inverted on the curved surface of the mold.
For example, in Patent Document 1, a flexible substrate corresponding to a fine structure is formed by photolithography, a curved matrix is formed by pasting the flexible substrate on the surface of a curved structure, and electroforming with metal is performed. Describes a method of manufacturing a microstructure that forms a metal microstructure.
Patent Document 1 describes that an outer lens having a light scattering surface is molded by arranging the metal microstructure in a mold and molding the metal microstructure.

JP 2009-155710 A

However, the conventional techniques as described above have the following problems.
When a metal microstructure formed by the technique described in Patent Document 1 is used as a stamper for nanoimprinting, a microstructure can be formed even when the work surface is curved, but the microstructure is a metal microstructure. However, it is limited to a shape that can be released. For example, in the case where the optical axis direction of the lens surface is the release direction, a fine structure composed of protrusions extending in a direction parallel to the optical axis can be formed, but from a set of protrusions extending in the normal direction of the lens surface The resulting fine structure has a problem that the fine structure is damaged at the time of mold release.
It is also possible to form a flat nanoimprint stamper with a deformable material and press the stamper against a curved work surface to follow the curved surface. There is a problem that pressure distribution occurs. For this reason, the uneven shape of the stamper is distorted or crushed at the part where the pressure applied to the stamper is high, and the adhesion between the curved surface and the stamper is deteriorated at the part where the pressure is low, and the height of the microstructure is uneven. There is a problem of becoming.
As described above, when the shape accuracy of the fine structure is poor, for example, when an antireflection structure is formed, the antireflection characteristic varies, and thus there is a problem that good antireflection characteristics cannot be obtained.

The present invention has been made in view of the above problems, and a surface shape molding method and a fine structure capable of accurately forming a fine structure with a plurality of concave and convex shapes on a curved work surface. The object is to provide a forming mold.
It is another object of the present invention to provide a method for manufacturing an optical element that can improve optical performance due to a fine structure provided on an optical surface.

  In order to solve the above-described problems, the surface shape molding method of the present invention is a surface shape molding method in which a microstructure having a plurality of uneven shapes is formed on a curved surface to be processed. A sheet-like mold member formed of a sheet-like elastic body, in which the plurality of concave-convex shapes are reversed and rearranged on one surface, and a shape compressed in the in-plane direction of the one surface is formed, A sheet-shaped mold member arranging step of arranging the mold holding member having an opening at one end so as to cross the opening, and the sheet-shaped mold member is stretched in a region on the inner peripheral side of the opening, and the curved shape of the work surface The sheet-shaped mold member deforming step for bending and deforming in accordance with the above, and after the liquid molding material is disposed on the processing surface, the curved and deformed sheet-shaped mold member is placed at a position close to the processing surface. Relative moving sheet A member moving step, and a sheet-shaped mold member pressing the sheet-shaped mold member adjacent to the processing surface from a surface opposite to the one surface and pressing the one surface against the processing surface A step of curing the molding material sandwiched between the sheet-shaped mold member and the work surface; and a separation step of separating the sheet-shaped mold member from the work surface after the molding material is cured. And a mold process.

  Further, in the surface shape molding method of the present invention, in the sheet-shaped mold member deformation step, by changing the pressure inside the mold holding member in a state where the opening is closed by the sheet-shaped mold member, The sheet-shaped mold member can be curved and deformed.

  In the surface shape molding method of the present invention, in the sheet-shaped mold member deformation step, the curved shape of the sheet-shaped mold member is brought into contact with the outer edge of the work surface. When it is made, it can be set as the shape where the envelope surface of the front-end | tip part of the said one surface of the said curved sheet-like member and the said to-be-processed surface are spaced apart except the contact part.

  Further, in the surface shape molding method of the present invention, in the sheet-shaped member deformation step, between the envelope surface of the tip of the one surface of the curved sheet-shaped member and the work surface, It is possible to have a shape in which a gap gradually increasing from the outer edge side toward the center side is formed.

  In the surface shape molding method of the present invention, the workpiece is an optical element substrate having a curved optical surface as the workpiece surface, and the microstructure is an antireflection structure in which weights are gathered. It is possible.

  The fine structure forming mold of the present invention is a fine structure forming mold for forming a fine structure having a plurality of concave and convex shapes on a curved work surface, and is formed of a sheet-like elastic body on one surface. The sheet-like mold member in which the plurality of concave and convex shapes are reversed and rearranged, and the shape compressed in the in-plane direction of the one surface is formed, and has an opening at one end, and crosses the opening A mold holding member in which the sheet-shaped member is arranged, and a sheet-shaped mold member deforming portion that stretches the sheet-shaped mold member in a region on the inner peripheral side of the opening and bends and deforms according to the curved shape of the processing surface. It is set as the structure provided with these.

  Further, in the microstructure forming mold of the present invention, the sheet-shaped mold member deforming portion changes the pressure inside the mold holding member in a state where the opening is closed by the sheet-shaped mold member, The sheet-shaped mold member can be curved and deformed.

  The method for producing an optical element of the present invention is a method including a step of forming the microstructure on the optical surface of an optical substrate having a curved optical surface using the microstructure forming mold of the present invention. .

  According to the surface shape molding method and the microstructure forming mold of the present invention, the sheet-like mold member made of a sheet-like elastic body is curved and deformed in accordance with the curved shape of the workpiece surface, and then the workpiece surface is formed. Since the fine structure is formed by pressing, there is an effect that a fine structure having a plurality of concave and convex shapes can be formed with high accuracy on a curved work surface.

In the typical top view which shows an example of the composition of the optical element manufactured by the molding method of the surface shape of a 1st embodiment of the present invention, the AA sectional view, the b section detailed drawing, and the c section detailed drawing is there. It is a typical block diagram of the surface processing apparatus containing the type | mold for microstructure formation of the 1st Embodiment of this invention. It is the typical top view of the sheet-like type | mold member used for the type | mold for microstructure formation of the 1st Embodiment of this invention, and its DD sectional drawing. It is typical process explanatory drawing which shows the manufacturing process of the sheet-like type | mold member used for the type | mold for microstructure formation of the 1st Embodiment of this invention. It is typical process explanatory drawing which shows the sheet-like mold member arrangement | positioning process of the surface shape shaping | molding method of the 1st Embodiment of this invention, and a sheet-like mold member deformation | transformation process. It is typical process explanatory drawing which shows the sheet-like type member moving process of the shaping | molding method of the surface shape of the 1st Embodiment of this invention, its e part detailed drawing, and f part detailed drawing. It is typical process explanatory drawing which shows the sheet-like type member press process of the shaping | molding method of the surface shape of the 1st Embodiment of this invention, and a mold release process. It is a schematic diagram explaining the effect | action of the shaping | molding method of a comparative example. FIG. 8 is a detailed view of a part k in FIG. 7. The typical top view which shows an example of a structure of the optical element manufactured by the shaping | molding method of the surface shape of the 1st modification of the 1st Embodiment of this invention, its GG sectional drawing, m part detailed drawing, and FIG. It is a typical block diagram of the surface processing apparatus containing the type | mold for microstructure formation of the 1st modification of the 1st Embodiment of this invention. It is typical process explanatory drawing which shows the sheet-like type member moving process of the shaping | molding method of the surface shape of the 1st modification of the 1st Embodiment of this invention, its v detailed drawing, and w detailed drawing. It is typical process explanatory drawing which shows the sheet-like type member press process of the shaping | molding method of the surface shape of the 1st modification of the 1st Embodiment of this invention. It is typical sectional drawing which shows the structure of the type | mold for microstructure formation of the 2nd modification of the 1st Embodiment of this invention. It is typical process explanatory drawing which shows the manufacturing process of the mold for fine structure formation of the 2nd modification of the 1st Embodiment of this invention. It is typical process explanatory drawing which shows the sheet-like type member deformation | transformation process of the shaping | molding method of the surface shape of the 3rd modification of the 1st Embodiment of this invention. It is a typical block diagram of the type for microstructure formation of the 2nd Embodiment of this invention. It is typical process explanatory drawing which shows the sheet-like mold member deformation | transformation process of the molding method of the surface shape of the 2nd Embodiment of this invention, and a sheet-like mold member press process.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
The surface processing apparatus used for the surface shape forming method of the first embodiment of the present invention will be described.
FIG. 1A is a schematic plan view showing an example of the configuration of an optical element manufactured by the surface shape molding method according to the first embodiment of the present invention. FIG.1 (b) is AA sectional drawing in Fig.1 (a). FIGS. 1C and 1D are a detailed view of a portion b and a detailed view of a portion c in FIG. FIG. 2 is a schematic configuration diagram of a surface processing apparatus including the microstructure forming mold according to the first embodiment of the present invention. FIG. 3A is a schematic plan view of a sheet-like mold member used for the microstructure forming mold according to the first embodiment of the present invention. FIG.3 (b) is DD sectional drawing in Fig.3 (a).

The surface shape forming method of the present embodiment is a surface shape forming method in which a fine structure having a plurality of uneven shapes is formed on a curved surface of a workpiece.
The type of workpiece and the shape of the fine structure are not particularly limited.
In the following, as an example, as shown in FIGS. 1A, 1 </ b> B, 1 </ b> C, and 1 </ b> D, the workpiece is the lens body 1 (optical element substrate), and the microstructure is the antireflection portion. An example of the antireflection structure according to 2 will be described.
That is, in this embodiment, an example in which the antireflection portion 2 is formed in the lens body 1 to manufacture the lens 1A that is an optical element will be described.

The lens body 1 is a single biconvex lens having a spherical convex lens surface 1a (surface to be processed, curved optical surface) and a spherical convex lens surface 1b (curved optical surface). A lens side surface 1c is formed on the outer periphery of the surfaces 1a and 1b.
The convex lens surfaces 1a and 1b are processed to have a surface shape and surface accuracy based on the design specifications of the lens before the antireflection portion 2 is formed. Hereinafter, the lens diameter of the lens body 1 is represented by D ₁ (see FIG. 1A), and the curvature radii of the convex lens surfaces 1a and 1b are represented by R _a and R _b , respectively (see FIG. 1B).
The material of the lens body 1 may be glass or synthetic resin. Further, the method of forming the convex lens surfaces 1a and 1b may be polishing or molding.
Below, in order to avoid the overlapping description, the antireflection part 2 will be described focusing on the antireflection part 2 formed on the convex lens surface 1a. Unless otherwise specified, the description of the antireflection portion 2 on the convex lens surface 1a can be similarly applied to the antireflection portion 2 on the convex lens surface 1b, if necessary, depending on the shape of the convex lens surface 1b. it can.

As shown in FIGS. 1C and 1D, the antireflection portion 2 is an aggregate of conical projections 2a arranged densely on the convex lens surface 1a.
In the present embodiment, the central axis of each protrusion 2a coincides with the direction of the normal N of the convex lens surface 1a at the position where each protrusion 2a is provided. However, the direction of the central axis of the protrusion 2a may be set to a direction inclined from the normal line N as long as the reflectance is within an allowable range, and does not need to be exactly coincident with the direction of the normal line N.
Moreover, each protrusion 2a is formed with UV curable resin as an example in this embodiment. As the type of the UV curable resin, a material in which the difference in refractive index is as small as possible is selected according to the refractive index of the material of the lens body 1. For example, in this embodiment, when the lens body 1 is a COP (cycloolefin polymer) resin (refractive index 1.5), the UV curable resin is PAK-02 (trade name; manufactured by Toyo Gosei Co., Ltd.) A refractive index of 1.5) is employed.
The shape of the protrusion 2a can be set as appropriate in accordance with the wavelength to prevent reflection and the target value of reflectance. In the present embodiment, as an example, to the reflectance of a convex lens surface 1a of the incident light having a wavelength 380nm~780nm to 1% or less, 200nm diameter _{d t} of the bottom surface, the height _{h t} is the 200nm projection 2a is uniformly distributed on the convex lens surface 1a with an adjacent pitch _pt of 200 nm. And wherein the distribution is uniform, meaning that average adjacent pitch p _t on convex lens surface 1a is constant, the individual adjacent pitch p _t is, for example, a variation due to manufacturing error It may be.
With such a configuration, on the convex lens surface 1a, the refractive index continuously changes from 1 to 1.5 in the range of 200 nm in height, so that reflection of incident light is suppressed.

  In this embodiment, such a lens 1A is manufactured using the surface processing apparatus 50 shown in FIG. Below, it demonstrates centering on the example in the case of forming the reflection preventing part 2 in the convex lens surface 1a with the surface processing apparatus 50. FIG.

  The schematic configuration of the surface processing apparatus 50 includes a holding unit 3, a UV light source 4, a microstructure forming mold 10, a mold moving unit 7, and a pressure control unit 8 (sheet-shaped mold member deforming unit). Moreover, although illustration is abbreviate | omitted, the operation control part which controls each operation | movement of the surface processing apparatus 50 is provided. The operation control performed by the operation control unit includes operation control of the mold moving unit 7 and operation control of the pressure control unit 8.

The holding unit 3 holds the lens body 1 when performing surface processing for forming the antireflection unit 2. In the present embodiment, the holding hole 3b is formed on the upper surface side, and the lens side surface 1c and the convex lens surface 1b are arranged with the optical axis O of the lens body 1 aligned with the vertical axis and the convex lens surface 1a facing upward. Can be held.
On the outer peripheral side of the holding hole 3b, a mold receiving surface 3c is formed on which a lower end surface of a microstructure forming mold 10 to be described later contacts.
A hole 3a that opens larger than the effective lens diameter of the lens 1A is provided through the center of the holding hole 3b.
The central axis of the hole 3 a is in a positional relationship aligned with the optical axis O of the lens body 1 held by the holding unit 3.

  The UV light source 4 is a light source that irradiates the lens body 1 with ultraviolet light (UV light), and is used to cure the UV curable resin applied to the convex lens surface 1a. In the present embodiment, the UV light source 4 is disposed below the holding unit 3 at a position overlapping the center of the hole 3a. For this reason, the UV light irradiated upward from the UV light source 4 passes through the hole 3a, enters the lens body 1, and is irradiated onto the entire surface of the convex lens surface 1a.

The microstructure forming mold 10 includes a mold holding member 6, a fixing member 9, and a film mold 5 (sheet-shaped mold member).
The mold holding member 6 is a bottomed cylindrical member in which an opening 6a having an inner diameter equal to or larger than the lens effective diameter of the lens body 1 is formed on one end side (the lower end side in FIG. 2), and the central axis Z is a vertical axis. They are arranged so as to be parallel and coaxial with the optical axis O of the lens body 1 held in the holding hole 3 b of the holding unit 3.
A lower end portion of a moving shaft 7a of the mold moving unit 7 to be described later is connected to the center portion of the upper surface 6f of the mold holding member 6. For this reason, the mold holding member 6 is held by the moving shaft 7a so as to be movable in the vertical direction.
A flow hole 6d is provided at the center of the hole bottom surface 6b of the mold holding member 6 so as to penetrate from the hole bottom surface 6b to the upper surface 6f. The flow hole 6 d forms a flow path for supplying or exhausting air inside the mold holding member 6.
The lower end surface 6c along the opening 6a of the mold holding member 6 is a plane orthogonal to the central axis Z, and can be fixed by sandwiching the outer peripheral portion of the film mold 5 with a fixing member 9 described later.
A male screw portion 6 e for screwing the fixing member 9 is formed on the outer peripheral side surface of the lower end portion of the mold holding member 6.
The material of the mold holding member 6 is not particularly limited as long as it has rigidity capable of withstanding internal pressure changes, and for example, a metal such as stainless steel can be employed.

The fixing member 9 is an annular member for fixing the outer peripheral portion of the film mold 5 to the lower end surface 6 c of the mold holding member 6, and has a cylindrical shape having a female screw portion 9 e that is screwed into the male screw portion 6 e of the mold holding member 6. The cylindrical portion 9 </ b> A and an annular portion 9 </ b> B that protrudes inward from one axial end side of the cylindrical portion 9 </ b> A and forms an end surface 9 d on one end side of the fixing member 9.
The end surface 9d is a plane orthogonal to the central axis of the cylindrical portion 9A. Further, the end face 9d is provided with a concave groove portion 9c penetrating in the radial direction at a plurality of locations in the circumferential direction.
A circular opening 9a larger than the outer diameter of the lens body 1 is formed at the center of the annular portion 9B.
In addition, a pressing surface 9b is formed on the back side of the end surface 9d in the annular portion 9B so as to face the lower end surface 6c of the die holding member 6 when the female screw portion 9e is screwed into the male screw portion 6e of the die holding member 6. Yes.

As shown in FIGS. 3A, 3B, and 3C, the film mold 5 has a convex lens surface 1a, which is a work surface, on one surface 5c of a sheet-like member having a constant thickness. It is a member on which a molding surface portion 5A having a fine uneven shape for forming the antireflection portion 2 is formed. The molding surface portion 5A is formed in a circular region excluding a part of the outer edge of the surface 5c.
Further, in the film mold 5, the back surface 5d opposite to the front surface 5c is a smooth surface.
The planar shape of the film mold 5 is a circle that covers the opening 6a and the lower end surface 6c of the mold holding member 6 in a state where the film mold 5 is not deformed by an external force (hereinafter referred to as a “natural state”). The member 6 is formed in a circular shape that matches the outer diameter of the lower end portion.
In the film mold 5, the annular region on the outer peripheral side of the molding surface portion 5 </ b> A has a certain thickness, and is sandwiched between the lower end surface 6 c of the mold holding member 6 and the pressing surface 9 b of the fixing member 9. A fixed part 5B to be fixed and held is configured.
The material of the film mold 5 is an elastic material having a better stretch property in the in-plane direction (direction perpendicular to the thickness direction) than the thickness direction, and can form a fine uneven shape on the surface. There is no particular limitation. As such an elastic material, for example, a material such as silicon rubber is suitable. In this embodiment, silicon rubber is employed as an example.

In such a film mold 5, as shown by a two-dot chain line in FIG. 2, the fixing member 9 is screwed onto the mold holding member 6 in a state where the fixed portion 5 </ b> B is in contact with the lower end surface 6 c of the mold holding member 6. By combining, the lower end surface 6c and the pressing surface 9b of the fixing member 9 are sandwiched and fixed.
However, since the film mold 5 fixed in this way is made of an elastic body, when an external force is applied in the out-of-plane direction, the range excluding the fixed part 5B on the outer peripheral side is deformed. The solid line in FIG. 2 shows the shape of the film mold 5 when receiving such an external force.
In the following, the shape of each part of the film mold 5 represents the shape of the natural state unless otherwise specified, and only when it is clearly stated that the shape of a specific deformation state is referred to, “ ",""", Etc.
For example, in FIG. 2, although the film type | mold 5 is drawn with the continuous line and the dashed-two dotted line, these are the same members. However, when referring to a solid line deformation state (a “deformation state before pressing” described later), it is referred to as a film mold 5 ″. Therefore, the shape of the molding surface portion 5A '' of the film mold 5 '' is different from that of the molding surface portion 5A in the natural state.

The molding surface portion 5A has a shape in which a concave shape obtained by inverting the irregularities of the shape of each projection 2a of the antireflection portion 2 is deployed on a plane corresponding to the surface 5c and compressed in the in-plane direction of the surface 5c. 5 is formed in the same range as the lens diameter of the convex lens surface 1 a of the lens body 1.
As shown in FIG. 3 (c), the molding surface portion 5 </ b> A of the present embodiment has a plurality of recessed hole portions 5 a corresponding to the protrusions 2 a of the antireflection portion 2 formed on the surface 5 c.
The shape and position of the recessed hole portion 5a is determined when the surface 5c of the film mold 5 is stretched in the in-plane direction and deformed into a concave surface that is in close contact with the convex lens surface 1a (hereinafter referred to as "work surface contact deformation state"). In other words, the concave and convex portions of the projections 2a in the antireflection portion 2 are set to have a concave shape. When each part in the work surface contact deformation state is indicated with a symbol “′”, the concave hole portion 5a ′ in the molding surface portion 5A ′ is in the in-plane direction of the surface 5c. This is a stretched shape, which matches the shape of the projections 2a of the antireflection portion 2 inverted.
For this reason, as will be described later, the shape of each concave hole portion 5a in the natural state is not necessarily the same shape, and the adjacent pitch varies depending on the part, but FIGS. 3A, 3B, and 3C are schematic diagrams. For this reason, the difference in individual shape of the recessed hole portion 5a and the difference in adjacent pitch are ignored and simplified.
Moreover, although the inner peripheral surface of the recessed hole part 5a comprises a part of outer surface of the film type | mold 5, below, the surface 5c in the molding surface part 5A is the surface before the recessed hole part 5a is formed. Shall mean. Therefore, the shape of the surface 5c in the molding surface portion 5A is defined by the envelope surface of the tip portion of the molding surface portion 5A, and the same applies to the molding surface portion 5A ′ or the like in which the molding surface portion 5A is curved.

FIG. 3C shows a case where a flat surface portion that forms a part of the surface 5c is left at the tip portion of the molding surface portion 5A, but depending on the shape of the antireflection portion 2, the molding is performed. 5 A of surface parts may have the uneven | corrugated shape at the front-end | tip part.
In this case, similarly, the shape of the surface 5c is defined by the envelope surface of the tip portion of the molding surface portion 5A.

In the present embodiment, the diameter d _t and adjacent pitch p _t of the bottom surface of the projection 2a of the anti-reflection portion 2 is a constant.
In addition, the film mold 5 is elastically deformable in the range inside the fixed part 5B because the fixed part 5B is fixed in the assembled state as the microstructure forming mold 10.
In the present embodiment, as will be described later, the film mold 5 is deformed by air pressure to be deformed into a film mold 5 ″ in a deformed state before pressing, and then pressed onto the convex lens surface 1a to be in a state of close contact with the work surface. The film mold 5 ′ is formed.
Conversion from the film-type 5 in a natural state to the film-type 5 ', since the circular plane of the outer diameter D _1, the diameter of the outer periphery is converted to deform the spherical segment shape of the curvature radius R _a equal to D _1, an outer If the diameter D ₁ , the radius of curvature R _a , and the material constant of the film mold 5 are given, the correspondence between each position of the surface 5c of the film mold 5 and each position of the surface 5c ′ of the film mold 5 ′ is obtained by calculation. It is done.
Thus, the shape of the 'recessed hole portions 5a on the' surface 5c is the opening diameter d _h0 antireflection portion _2, and inversely transforms the adjacent pitch p shape conical hole shape irregularities of the projections 2a and reversal of _h0, The compression-deformed shape on the surface 5c can be calculated.

For this reason, in the molding surface portion 5A, in the case of the recessed hole portion 5a in which the hole central axis n is located at a position where the distance from the central axis C along the surface 5c is x, as shown in FIG. other but, _d r (x) in the radial direction, it is at a not shown circumferential d _theta (x), the depth h (x) = ellipse _{h t} Kiriana (conditions including a conical hole by), adjacent The adjacent pitch with the recessed hole portion 5a is p _r (x) in the radial direction and p _θ (x) in the circumferential direction (not shown). Moreover, the hole center axis n of the recessed hole portion 5a is aligned with the normal line of the surface 5c.

  As shown in FIG. 2, the mold moving unit 7 is disposed above the mold holding member 6. The schematic configuration of the mold moving unit 7 is such that the lower end is connected to the center of the upper surface 6f of the mold holding member 6 and holds the moving shaft 7a arranged in parallel to the vertical axis and the upper end of the moving shaft 7a. An axis moving mechanism 7b for moving the moving axis 7a back and forth along the vertical axis.

  Inside the moving shaft 7a, a pipe line 7c connected to the upper end portion of the flow hole 6d of the mold holding member 6 and communicating with the flow hole 6d is provided. The other end of the pipe line 7c is connected to the pressure control unit 8 via a tube 8a on the side of the shaft moving mechanism 7b.

The shaft moving mechanism 7b is fixed above the holding portion 3 by a support member (not shown).
The shaft moving mechanism 7b is electrically connected to an operation control unit (not shown) that controls the amount of movement of the moving shaft 7a.
As a specific configuration of the shaft moving mechanism 7b, a configuration such as an actuator using a drive mechanism such as a motor or a fluid-driven actuator such as an air cylinder can be adopted.

  The pressure control unit 8 includes a pump that exhausts air from the inside of the mold holding member 6 or supplies air to the inside of the mold holding member 6 via a tube 8a connected to the pipe line 7c. This adjusts the air pressure in a pressure change chamber P, which will be described later.

Next, an example of a surface shape forming method for forming the antireflection portion 2 on the optical surface of the lens body 1 using the surface processing apparatus 50 and an example of a method for manufacturing the lens 1A using the surface shape forming method will be described.
4 (a), 4 (b), 4 (c), and 4 (d) are schematic process explanatory views showing the manufacturing process of the sheet-shaped mold member used for the microstructure forming mold according to the first embodiment of the present invention. It is. FIGS. 5A and 5B are schematic process explanatory views showing a sheet-shaped member arranging step and a sheet-shaped member deforming step of the surface shape molding method according to the first embodiment of the present invention. . Fig.6 (a) is typical process explanatory drawing which shows the sheet-like type member moving process of the shaping | molding method of the surface shape of the 1st Embodiment of this invention. FIGS. 6B and 6C are a detailed view of the portion e and a detailed view of the portion f in FIG. FIGS. 7A and 7B are schematic process explanatory views showing a sheet-like mold member pressing step and a releasing step of the surface shape molding method according to the first embodiment of the present invention. FIGS. 8A and 8B are schematic diagrams for explaining the operation of the molding method of the comparative example. FIG. 9 is a detailed view of a portion k in FIG. 7B.

  The surface shape molding method of the present embodiment is as follows. First, after the film mold 5 is manufactured, a sheet-shaped mold member arranging process, a sheet-shaped mold member deforming process, a sheet-shaped mold member moving process, a sheet-shaped mold member pressing process, and curing. In this method, the process and the mold release process are performed in this order. However, since the sheet-shaped mold member deformation process may be performed before the sheet-shaped mold member moving process is completed, it may be performed in parallel with the on-sheet mold member moving process. Hereinafter, as an example, a case where the sheet-shaped member moving process is performed after the sheet-shaped member deformation process is completed will be described.

First, the process of manufacturing the natural film mold 5 will be described.
In order to manufacture the film mold 5, first, the shape of the molding surface part 5A of the film mold 5 in the natural state is determined based on the shape of the molding surface part 5A 'in the work surface contact deformation state determined from the shape of the antireflection part 2. To do.
When the shape of the molding surface portion 5A is determined, the production of the film mold 5 is started.
First, as shown in FIG. 4A, a master base material 11 made of, for example, a flat plate member made of silicon is prepared, and a molding surface portion 5A is formed on a base material surface 11a which is one plate surface of the master base material 11. The inversion fine structure 12 including a plurality of recessed hole portions 12a matched with the shape of the recessed hole portion 5a is formed.
Here, in FIG. 4 (a) (the same applies to FIGS. 4 (b), (c), and (d)), in order to show that _dr (x) and _pr (x) change with x, The case where the shape and the adjacent pitch differ depending on x is schematically drawn exaggeratingly.
Such a reverse microstructure 12 can be formed by applying a resist on the substrate surface 11a, exposing the shape pattern with an electron beam drawing apparatus, and then removing the exposed portion.

Next, as shown in FIG. 4B, the etching beam 14 is irradiated along the normal direction of the substrate surface 11a using a dry etching apparatus, and the anisotropy is performed until the inverted microstructure 12 is removed. Etching is performed.
As a result, at each position of the substrate surface 11a, etching proceeds in the normal direction of the substrate surface 11a along the outer shape of the inverted microstructure 12, and the shape of the inverted microstructure 12 becomes the master substrate 11. Transcribed. Thereby, the inversion fine structure part 11b of the master base material 11 is formed.
Hereinafter, the master base material 11 on which the inverted fine structure portion 11b is formed is referred to as a master die 11A.

Next, as shown in FIG. 4C, the inverted mold 13 is formed using the master mold 11A as a mother mold. For example, the reverse mold 13 is formed by applying a UV curable resin on a transparent flat substrate such as glass and performing fine structure transfer using UV imprinting. Further, the reversal mold 13 can be produced by pressing the master mold 11A against the resin film under heating.
As a result, a flat plate-like reversal mold 13 having the fine structure portion 13a having the reversed shape of the reversal fine structure portion 11b on the surface is obtained. Since the shape of the fine structure portion 13a is a shape obtained by inverting the inverted fine structure portion 11b, it is a convex shape as a whole in which elliptical cone-shaped protrusions are densely arranged.
The master mold 11A may be omitted and the reversal mold 13 may be manufactured. However, in etching, it is easier to manufacture a concave shape than a convex shape, and the shape accuracy is good. Become. For this reason, in this embodiment, the manufacturing method which produces 11 A of concave shape masters is employ | adopted.

Next, as shown in FIG. 4 (d), the reversal mold 13 is used as a mother mold of the molding surface portion 5A, and a mold frame (not shown) for forming the outer shape of the film mold 5 is formed. A liquid UV is formed on the mold mold. A film mold 5 is formed by introducing and curing a curable or thermosetting resin. Examples of the curing means include a thermal method and a photocuring method. In the present embodiment, a photocuring method using UV light is employed.
In this way, the film mold 5 having the molding surface portion 5A is manufactured.
This completes the mold manufacturing process.

In addition, the manufacturing method of said film type | mold 5 is an example, Comprising: It can deform | transform suitably.
For example, when forming the master mold 11A, selective etching such as aluminum anodization may be employed instead of dry etching.

Next, a sheet-shaped member arrangement step is performed. As shown in FIG. 5A, this step is a step of forming the microstructure forming die 10 by disposing the film die 5 so as to cross the opening 6 a of the die holding member 6.
This step may be performed with the mold holding member 6 removed from the mold moving unit 7 or may be performed with the mold holding member 6 attached to the mold moving unit 7. FIG. 5A shows a state in which the microstructure forming mold 10 has already been formed and attached to the mold moving unit 7.

The film mold 5 is attached in such a manner that the fixed portion 5B and the lower end surface 6c of the mold holding member 6 are overlapped with the surface 5c of the film mold 5 facing the outside of the mold holding member 6. At this time, it arrange | positions so that the film type | mold 5 may maintain the planar shape of a natural state, without sagging within the opening 6a. For example, if an appropriate holding jig or the like that holds the surface 5c of the molding surface portion 5A is used, the natural surface can be maintained.
Next, in this state, the fixing member 9 is screwed into the mold holding member 6, and the pressing surface 9 b of the fixing member 9 is brought into contact with the fixed portion 5 </ b> B of the film mold 5. As a result, the fixed portion 5B is fixed and held between the pressing surface 9b and the lower end surface 6c.
Note that when this work is performed with the mold holding member 6 attached to the mold moving unit 7, the pressure control unit 8 is stopped.

In this manner, the film mold 5 is fixed to the mold holding member 6 in a natural planar shape, and the microstructure forming mold 10 is assembled.
The film mold 5 closes the opening 6 a of the mold holding member 6 with the molding surface portion 5 </ b> A facing the outside of the mold holding member 6, and is fixed in close contact with the lower end surface 6 c of the mold holding member 6.
Thereby, since the opening 6a is hermetically closed by the film mold 5, a pressure change chamber P in which the pressure is changed by supplying or exhausting air from the flow hole 6d is formed inside the mold holding member 6.
When the microstructure forming mold 10 is arranged above the holding part 3, the sheet-like mold member arranging step is completed.

Next, a sheet-shaped member deformation process is performed. As shown in FIG. 5 (b), this step is a step in which the film mold 5 is stretched in a region on the inner peripheral side of the opening 6a so as to be curved and deformed in accordance with the curved shape of the convex lens surface 1a that is the processing surface. Here, “according to the curved shape” means that the concave and convex curved directions are the same and the magnitudes of the curvatures are substantially the same (including the case where they are matched). It doesn't mean just an exact match.
In the present embodiment, an operation control unit (not shown) drives the pressure control unit 8 to suck and exhaust the air in the pressure change chamber P, thereby reducing the pressure in the pressure change chamber P.
Thereby, an atmospheric pressure higher than the internal pressure of the pressure change chamber P acts on the molding surface portion 5 </ b> A of the film die 5, so that the film die 5 is pressed toward the inside of the pressure change chamber P. As a result, in a state where the fixed portion 5B is fixed, the film mold 5 on the inner peripheral side of the fixed portion 5B is stretched in the in-plane direction. As a result, the film mold 5 is curved and deformed into a dome shape, and a film mold 5 ″ is formed.

The deformation state of the curvature of the surface 5c of the film mold 5 is the surface 5c '' in the deformed state before pressing shown in FIG.
The curved shape of the surface 5c '' in the deformed state before pressing is such that when the surface 5c '' is pressed toward the convex lens surface 1a in the sheet-shaped mold member pressing step, which will be described later, the film mold 5 and the convex lens surface 1a. The shape is such that it can smoothly contact and smoothly adhere to the convex lens surface 1a.
Specifically, in the process in which the surface 5c '' is deformed into a shape along the convex lens surface 1a by pressing, a tensile stress in the in-plane direction of the surface 5c '' does not occur or even if it occurs, the molding surface portion 5A ' A shape whose deformation is within an allowable range.

As such a curved shape of the surface 5c ″, when the surface 5c ″ is brought into contact with the outer edge of the convex lens surface 1a, the space between the convex lens surface 1a and the surface 5c ″ excluding the contact portion is formed. By separating, a shape with a gap can be cited (hereinafter referred to as “centrally spaced curved shape”).
In this case, the surface 5c '' is separated from the convex lens surface 1a except for a circular contact portion with the convex lens surface 1a on the outer peripheral side. In addition, since the surface area of the surface 5c ″ is larger than the surface area of the convex lens surface 1a, the surface to be processed has a curved shape that is further contracted in the in-plane direction. That is, the film mold 5 ″ can approach the convex lens surface 1a while contracting in the space above the convex lens surface 1a, and therefore can be in close contact with the convex lens surface 1a very smoothly.
In this case, the gap formed between the surface 5c ″ and the convex lens surface 1a is more preferably a gap that gradually increases from the outer edge side toward the center side.
Here, the maximum value of the gap in each case is not particularly limited. However, since the deformation load of the film mold 5 ″ is preferably small, for example, it is preferably limited to a range of 0.1 mm to 2.0 mm.
These curved shapes, for example, surface 5c '' when it is spherical, the curvature radius R _{5c ''} (see FIG. 5 (b)) is, if smaller than the radius of curvature R _a of the convex lens surface 1a That's fine.
However, the surface 5c '' is not limited to a spherical surface as long as it is a concave curved surface capable of forming such a gap. That is, it may be a curved surface in which the curvature of the surface 5c '' is larger than the curvature of the convex lens surface 1a as a whole.

'Other curved shape of the surface 5c' surface 5c '' radius of curvature R _5c of _'' is can be exemplified case match the curvature radius R _a of the convex lens surface 1a (hereinafter, "contact type Called "curved shape").
In this case, since the entire surface 5c '' can be brought into close contact with the convex lens surface 1a at the same time, no tensile stress is generated in the in-plane direction during pressing.

'Still other curved shape of the surface 5c' surface 5c '' radius of curvature R _5c of _'' is a larger than the radius of curvature R _a of the convex lens surface 1a, the difference between these radii of curvature is small Examples of cases can be given (hereinafter referred to as “periphery-separated curved shape”).
In this case, when the surface 5c '' is brought closer to the convex lens surface 1a, contact with the convex lens surface 1a is started from the center of the surface 5c '', and the film mold 5 '' is stretched on the outer peripheral side of the contact portion. By this, it adheres to convex lens surface 1a.
At this time, a tensile stress that changes with the progress of the contact is generated on the outer peripheral side of the contact portion in the film mold 5 ″, but as the curvature radius of the surface 5c ″ is closer to the curvature radius of the convex lens surface 1a, the generated tensile stress is generated. Since the stress is also reduced, uneven deformation of the molding surface portion 5A ″ due to tensile stress can be reduced.
The size and the lens body 1, depending on the shape accuracy required for the anti-reflection portion 2, the size of the radius of curvature R _{5c '',} 1.0 times 0.7 times the size of the radius of curvature R _a It is preferable that
If the surface 5c '' is not a spherical surface, the maximum value of the gap generated between the surface 5c '' and the convex lens surface 1a when part of the surface 5a '' abuts on the convex lens surface 1a is set to an appropriate value. That's fine. The allowable value of the maximum value of the gap is preferably 0.1 mm to 2.0 mm, for example, depending on the size of the lens body 1 and the shape accuracy required for the antireflection portion 2.

In the present embodiment, a center-separated curved shape is adopted as an example of the surface 5c ″, and the maximum value d of the gap when the outer edge of the surface 5c ″ is brought into contact with the outer edge of the convex lens surface 1a (FIG. 6 ( c) is set to be 0.1 mm.
The internal pressure of the pressure change chamber P necessary to form such a surface 5c '' is, for example, the relationship between the pressure acting on the molding surface portion 5A when the outer edge of the film mold 5 is fixedly supported and the curved shape, It may be obtained in advance by performing a simulation or experiment.
This completes the sheet-shaped member deformation process.
In the center-separated curved shape, even if the gap size d slightly changes, the surface 5c '' and the convex lens surface 1a are not in contact with each other except the outer edge portion. Compared to the curved shape, the tolerance of the variation in the curved shape of the surface 5c '' is increased.

  Next, a sheet-shaped member moving process is performed. In this step, as shown in FIG. 5, after the UV curable resin 20 that is a liquid molding material is disposed on the convex lens surface 1a (see FIG. 5B), the curved film mold 5 ″ is converted into a convex lens. This is a process of relative movement to a position close to the surface 1a (see FIG. 6A). In the present embodiment, the position of the convex lens surface 1a is fixed, and a relative movement is performed in which the microstructure forming mold 10 is moved toward the convex lens surface 1a.

First, as shown in FIG. 5B, prior to this step, for example, the lens body 1 manufactured by performing appropriate processing such as cutting / polishing, glass mold molding, resin molding, etc., and the convex lens surface 1a is a film. It is held by the holding unit 3 of the surface processing apparatus 50 in a posture facing the mold 5.
Next, the UV curable resin 20 is disposed on the convex lens surface 1a. In this embodiment, PAK-02 (trade name) is adopted as the type of the UV curable resin 20 as an example.
As shown in FIG. 5B, the UV curable resin 20 may be applied to the central portion in a lump shape and spread on the outer peripheral portion when pressing the film mold 5 as will be described later. For example, the entire surface of the convex lens surface 1a may be applied in layers by spin coating or the like.

Next, the shaft moving mechanism 7b (see FIG. 2) is driven via an operation control unit (not shown), and as shown in FIG. 6 (a), the moving shaft 7a is moved vertically downward, and the outer edge of the convex lens surface 1a. The microstructure forming mold 10 is lowered until the surface 5c ″ contacts with the surface 5c ″.
In the present embodiment, when the end surface 9d of the fixing member 9 and the mold receiving surface 3c of the holding portion 3 come into close contact with each other, the corner j of the boundary with the lens side surface 1c that is the outer edge of the convex lens surface 1a (FIG. 6B). Reference) and the surface 5c ″ are in contact with each other.
At this time, in this embodiment, the internal pressure of the pressure change chamber P is set to the same pressure as that in the sheet-shaped mold member deformation step so as to maintain a centrally spaced curved shape.
As a result, as shown in detail in FIGS. 6B and 6C, a gap S is formed between the convex lens surface 1a inside the corner j and the surface 5c ''.
In the present embodiment, the height dimension of the gap S gradually increases from the outer peripheral side toward the center side, and has a maximum value d at the center of the convex lens surface 1a.
However, in the present embodiment, since the maximum value d of the gap S is lower than the coating height of the UV curable resin 20, as shown in FIG. 6C, the UV curable resin 20 is at the center of the convex lens surface 1a. The film is pressed by the film mold 5 ″, filled in the recessed hole portion 5a ″, and spread outward in the radial direction.
Thus, the sheet-shaped mold member moving step is completed.

Next, a sheet-shaped member pressing process is performed. This step is a step of pressing the film mold 5 ″ adjacent to the convex lens surface 1a from the back surface 5d ″ opposite to the front surface 5c ″ to deform the surface 5c ″ and press it against the convex lens surface 1a. .
In the present embodiment, an operation control unit (not shown) drives the pressure control unit 8 (see FIG. 2) with the position of the microstructure forming mold 10 fixed, as shown in FIG. 7A. Then, the pressure in the pressure change chamber P is supplied to increase the pressure in the pressure change chamber P.
As a result, the film mold 5 ″ shrinks in the in-plane direction and the surface 5c ″ is brought into close contact with the convex lens surface 1a, so that the film mold 5 ′, the surface 5c ′, and the molding surface portion 5A ′ in the work surface contact deformation state are formed. It is formed.
At that time, the UV curable resin 20 sandwiched between the surface 5c ″ and the convex lens surface 1a has a gap S that is narrowed as the surface 5c is deformed from the surface 5c ″ to the surface 5c ′. Will be spread out. At this time, the air in the gap S is also pushed to the outer peripheral side, but since it can leak out from the recessed groove portion 9c of the fixing member 9 to the outside of the microstructure forming mold 10, the UV curable resin 20 can be moved to the outer peripheral side without any trouble. Moving.
Thus, the sheet-shaped mold member pressing step is completed.

In the sheet-shaped member pressing process of the present embodiment, the surface 5c is deformed from the center-separated curved surface 5c '' to the surface 5c 'in the state of close contact with the work surface, so that the dome shape has a larger surface area than the convex lens surface 1a. Then, the film is contracted and deformed by the elastic restoring force of the film mold 5 ″. For this reason, even if the pressing force is applied by the internal pressure of the pressure change chamber P, the reaction force from the convex lens surface 1a does not act until the surface 5c ′ is in close contact with the convex lens surface 1a. It will be transformed.
For this reason, slippage between the surface 5c and the convex lens surface 1a hardly occurs during the pressing process, and the shape accuracy of the molding surface portion 5A ′ is improved.

This point will be described in contrast to the comparative example shown in FIGS.
In this comparative example, as shown in FIG. 8A, the film mold 5 is fixed to the opening 106a of the cylindrical mold holding member 106 in the natural state. And as shown in FIG.8 (b), such a planar film type | mold 5 is pressed on the convex lens surface 1a, without curving previously.
In this case, as shown in FIG. 8B, the central portion of the molding surface portion 5A abuts on the convex lens surface 1a, the abutting range is expanded on the outer peripheral side, and the surface 5c is curved into a shape along the convex lens surface 1a. The
At this time, since the pressing force is applied to the abutting portion, the frictional force from the convex lens surface 1a acts and the deformation in the in-plane direction is suppressed. For this reason, the larger the abutment portion is on the outer peripheral side, the larger the tensile stress is applied and the more it is stretched. As a result, as compared with the present embodiment, a large strain is generated on the outer peripheral side of the molding surface portion 5A, and the shape accuracy of the molding surface portion 5A in the close contact state is deteriorated.

  Even in the present embodiment, if the surface 5c '' is a peripherally spaced curved surface in the sheet-shaped member deformation step, the sheet-shaped member moving step comes into contact with the convex lens surface 1a from the center of the surface 5c ''. Since it is already curved in a dome shape similar to that of the substantially convex lens surface 1a from the flat state, the strain at the time of pressing is significantly smaller than that of the comparative example, and the shape accuracy of the molding surface portion 5A can be kept within an allowable range. It is.

Next, a curing process is performed. This step is a step of curing the UV curable resin 20 sandwiched between the film mold 5 ′ and the convex lens surface 1a.
By the sheet-shaped member pressing step, the surface 5c ′ and the convex lens surface 1a are brought into close contact with each other, and the molding space between them is filled with the UV curable resin 20.
In this step, as shown in FIG. 7A, the UV light source 4 is turned on while the internal pressure of the pressure change chamber P is maintained. Thereby, ultraviolet light enters the lens body 1 from the hole 3a, and UV light is irradiated from the inside of the lens body 1 to the convex lens surface 1a.
As a result, the UV curable resin 20 filled in the molding space sandwiched between the convex lens surface 1a and the molding surface portion 5A ′ is photocured, and the antireflection portion 2 is formed on the convex lens surface 1a.
When the curing of the UV curable resin 20 is completed, the UV light source 4 is turned off.
This completes the curing process.

Next, a mold release process is performed. This step is a step of separating the film mold 5 ′ from the convex lens surface 1a after the UV curable resin 20 is cured.
In this step, as shown in FIG. 7B, the mold moving unit 7 is driven by an operation control unit (not shown) to raise the microstructure forming mold 10 and the film mold 5 ′ is moved from the convex lens surface 1a. Let mold release. At this time, the internal pressure of the pressure change chamber P is set to be equal to or higher than the internal pressure at which the film mold 5 has a close-contact curved shape. As a result, the microstructure forming mold 10 is raised and the film mold 5 is pushed downward, so that the film mold 'can be gradually released from the outer peripheral side of the convex lens surface 1a toward the center.
At this time, at the part to be released, as shown in FIG. 9, the film mold 5 is released so as to be gradually lifted upward from the convex lens surface 1a. For this reason, since the recessed hole part 5a moves along the protrusion direction of the protrusion 2a which protrudes in the normal line direction of the convex lens surface 1a, mold release resistance decreases. As a result, the protrusion 2a can be released without being deformed or damaged.
Since the shape of the film mold 5 that rises at the part to be released is determined by the relationship between the movement position of the microstructure forming mold 10 and the internal pressure of the pressure change chamber P, it gradually increases as the microstructure forming mold 10 rises. By increasing the internal pressure of the pressure change chamber P, a smoother mold release becomes possible.

In this way, when the film mold 5 is separated from the convex lens surface 1a, the mold release process is completed.
Thereby, the lens 1A in which the antireflection portion 2 is formed on the convex lens surface 1a is manufactured.

Furthermore, when forming the antireflection part 2 on the convex lens surface 1b, the film mold 5 is replaced with another film mold 5 for molding the convex lens surface 1b as necessary, and the same process as above is performed. repeat. However, since the film mold 5 is made of an elastic body, if the curvature of the convex lens surface 1b is not so different from that of the convex lens surface 1a, the film mold 5 having the same shape as the convex lens surface 1a can be used.
In this way, the lens 1A can be manufactured.

  According to the surface shape molding method of the present embodiment, the film mold 5 made of a sheet-like elastic body is a surface to be processed by using the microstructure forming mold 10 and the surface processing apparatus 50 into which the microstructure is inserted. It is curved and deformed according to the curved shape of the convex lens surface 1a. Thereafter, the antireflection portion 2 that is a fine structure having a plurality of concave and convex shapes is pressed against the convex lens surface 1a, so that a fine structure having a plurality of concave and convex shapes can be accurately formed on the curved processed surface. .

Further, the microstructure forming mold 10 includes a film mold 5 made of an elastic body and a mold holding member 6 having a pressure change chamber P that curves the film mold 5. A fine structure can be formed on a work surface having various curvatures.
Therefore, the entire surface of the film mold 5 can be processed from one direction by, for example, anisotropic etching. As a result, it is possible to easily and efficiently form the molding surface portion 5A as compared with the case of forming a curved surface.
Thus, the film mold 5 is easier to manufacture and can be more versatile than a curved surface mold having a fixed curvature.

In addition, the microstructure forming mold 10 protrudes in a normal direction, for example, on a work surface having various curvatures by bending the film mold 5 by using the film mold 5 made of an elastic body. A fine structure including protrusions can be easily formed. Moreover, since the film mold 5 can be released while being deformed at the time of mold release, the mold can be released by changing the mold release direction for each fine structure. It is possible to release the mold without deforming or damaging the microstructure protruding to the surface.
For this reason, it is possible to form a fine structure with good shape accuracy, and it is particularly suitable for forming a fine structure of an optical element that exhibits optical characteristics such as an antireflection structure.

[First Modification]
A surface shape molding method according to a first modification of the present embodiment will be described.
FIG. 10A is a schematic plan view showing an example of the configuration of an optical element manufactured by the surface shape molding method according to the first modification of the first embodiment of the present invention. FIG.10 (b) is the GG sectional drawing in Fig.10 (a). FIGS. 10C and 10D are a detailed view of the m portion and a detailed view of the n portion in FIG. FIG. 11 is a schematic configuration diagram of a surface processing apparatus including a microstructure forming mold according to a first modification of the first embodiment of the present invention.

This modification is a method of forming a surface shape when the surface to be processed is concave, and can be performed using the surface processing apparatus 50 of the first embodiment.
Hereinafter, as an example, as illustrated in FIGS. 10A, 10 </ b> B, 10 </ b> C, and 10 </ b> D, the workpiece is the lens body 21 (optical element base material), and the fine structure is the first structure. It is assumed that the antireflection part 2 is the same as that of the first embodiment, and the difference from the first embodiment is mainly described.
That is, in this modification, an example in which the antireflection portion 2 is formed in the lens body 21 to manufacture the lens 21A that is an optical element will be described.

The lens body 21 is a _single concave lens having a concave lens surface 21a (curved optical surface) made of a concave spherical surface having a radius of curvature Ra and _a lens diameter D1, and a flat lens surface 21b made of a flat surface. is there. A flat surface portion 21d parallel to the flat lens surface 21b is formed on the outer peripheral side of the concave lens surface 21a of the lens body 21, and a lens side surface 21c is formed on the outer periphery of the flat surface portion 21d and the flat lens surface 21b.
The antireflection part 2 of the present modification differs from the first embodiment only in that the projections 2a similar to those of the first embodiment are formed on the concave lens surface 21a. The shape and arrangement pitch of the projections 2a are the same as those of the first embodiment. It is the same as the form. That is, the projection 2a is conical with a diameter of the bottom surface is _{d t,} height _{h t,} adjacent pitch between the projections 2a is _{p t.}
The material of the lens body 21 may be glass or synthetic resin. Further, the method of forming the concave lens surface 21a and the flat lens surface 21b may be polishing or molding.

As shown in FIG. 11, the surface processing apparatus 50 of the present modification has the same configuration as that of the first embodiment, and corresponds to the fact that the surface to be processed is the concave lens surface 21a. The only difference is that 5 is curved into a convex surface.
However, the molding surface portion 5A of the film mold 5 of the present modification is formed in a shape in which the projections and recesses of the protrusions 2a of the antireflection portion 2 are inverted in a state where the processing surface is in close contact with the concave lens surface 21a. Since the convex lens surface 1a and the concave lens surface 21a have the same radius of curvature, they have substantially the same shape except that the diameter of each concave hole portion 5a of the molding surface portion 5A of this modification is slightly smaller.

Next, the surface shape forming method of this modification will be described.
Fig.12 (a) is typical process explanatory drawing which shows the sheet-like mold member movement process of the shaping | molding method of the surface shape of the 1st modification of the 1st Embodiment of this invention. FIGS. 12B and 12C are a detailed view of a portion r and a detailed view of a portion s in FIG. 12A. FIG. 13 is a schematic process explanatory view showing a sheet-like mold member pressing step of the surface shape forming method of the first modified example of the first embodiment of the present invention.

The surface shape molding method of the present modification example is as follows. First, after the film mold 5 having the molding surface portion 5A having the shape of the present modification example is manufactured, a sheet-shaped mold member arranging step, as in the first embodiment, In this method, the sheet-shaped member deformation process, the sheet-shaped member movement process, the sheet-shaped member pressing process, the curing process, and the release process are performed in this order.
Hereinafter, a description will be given centering on differences from the first embodiment.

  The sheet-like mold member arranging step of this modification is the same as the sheet-like member arranging step of the first embodiment. Thereby, the microstructure forming mold 10 including the film mold 5 indicated by a two-dot chain line in FIG. 11 is formed.

As shown in FIG. 11, the sheet-shaped mold member deformation process of this modification is different from the first embodiment in that the surface 5c '' of the film mold 5 '' in a deformed state before pressing becomes a convex surface. .
For this reason, in this modification, the convex dome-shaped surface 5c '' is formed by supplying air from the pressure control unit 8 and increasing the internal pressure of the pressure change chamber P above the atmospheric pressure.
The shape of the surface 5c '' of this modification may be any of the center-separated curved shape, the contact-type curved shape, and the peripheral-spaced curved shape. Since these shapes in this modification can be easily understood from the description of the first embodiment, the center-separated curved shape of this modification will be described as an example.

In the center-separated curved shape of this modification, when the surface 5c ″ is brought into contact with the outer edge of the concave lens surface 21a, the gap between the concave lens surface 21a and the surface 5c ″ excluding the contact portion is determined. This is a shape with a gap. In the case of this modification, the film mold 5 is stretched from a natural planar shape to form a curved shape, and the film mold 5 ″ is pressed with the concave lens surface 21a before being pressed toward the concave lens surface 21a. It is separated from the concave lens surface 21a except for the circular contact portion.
However, in this modification, since the surface area of the surface 5c '' is smaller than the surface area of the concave lens surface 21a, deformation that is stretched in the in-plane direction occurs during pressing, and tensile stress is generated in the film mold 5 ''. . However, even if such a tensile stress occurs, the film mold 5 '' can be stretched without coming into contact with the concave lens surface 21a in the space above the concave lens surface 21a and approach the concave lens surface 21a. Therefore, it is possible to contact the concave lens surface 21a very smoothly.
The gap formed between the surface 5c '' and the concave lens surface 21a is more preferably gradually increased from the outer edge side toward the center side, and the maximum value of the gap is, for example, 0.1 mm to 2. The fact that it is preferable to stay within the range of 0 mm is the same as in the first embodiment.

Next, a modified sheet-like member moving step is performed.
In this step, as shown in FIG. 11, the lens body 21 is held by the holding unit 3 and the UV curable resin 20 is disposed on the concave lens surface 21a.
Next, as shown in FIG. 12A, the curved film mold 5 ″ is moved to a position close to the convex lens surface 1a, and the corner angle with the flat portion 21d which is the outer edge of the concave lens surface 21a. The microstructure forming mold 10 is lowered until the part u (see FIG. 12B) and the surface 5c ″ contact each other.
In this modification, when the end surface 9d of the fixing member 9 and the mold receiving surface 3c of the holding portion 3 are in close contact with each other, the corner portion u and the surface 5c '' are in contact with each other. A gap S is formed between the inner concave lens surface 21a and the surface 5c ''. The height dimension of the gap S in this modification example gradually increases from the outer peripheral side toward the center side, and is the maximum value d in the center of the concave lens surface 21a as in the first embodiment.
Thus, the sheet-shaped mold member moving step is completed.

  Next, as shown in FIG. 13, the sheet-shaped member pressing process and the curing process of the present modification are performed. These steps are the same as those in the first embodiment.

Next, the mold release process of this modification is performed. In this step, the microstructure forming mold 10 is raised and exhausted from the pressure change chamber P to reduce the pressure.
As a result, the film mold 5 deforms so as to sag from the outer peripheral side. Therefore, unlike the parallel movement of the same curved shape, the film mold 5 is released so as to be gradually raised upward from the outer peripheral side of the concave lens surface 21a. . For this reason, as in the first embodiment, since the concave hole portion 5a moves substantially along the protruding direction of the protrusion 2a protruding in the normal direction of the concave lens surface 21a, the mold release resistance is reduced. As a result, the protrusion 2a can be released without being deformed or damaged.

In this way, when the mold release step is completed, a lens 21A in which the antireflection portion 2 is formed on the concave lens surface 21a as shown in FIGS. 10A and 10B is manufactured.
In this modification, for simplicity, although the radius of curvature of the concave lens surface 21a has been described in example when R _a, the radius of curvature of the concave lens surface 21a is not limited to R _a, there is a different concave shape However, the antireflection part 2 can be formed.

[Second Modification]
Next, a microstructure forming mold according to a second modification of the present embodiment will be described.
FIG. 14 is a schematic cross-sectional view showing the configuration of a microstructure forming mold according to a second modification of the first embodiment of the present invention. FIGS. 15A and 15B are schematic process explanatory views showing the manufacturing process of the microstructure forming mold of the second modified example of the first embodiment of the present invention.

The microstructure forming mold 30 of this modification includes a fixing member 39 instead of the fixing member 9 of the microstructure forming mold 10 of the first embodiment.
The fixing member 39 is an annular member that is detachably fixed to the lower end portion of the mold holding member 6. Like the fixing member 9, the fixing member 39 has a female screw portion 9 e on the inner peripheral portion, and the female screw portion 9 e is connected to the die holding member 6. A fixed surface 39a constituted by a plane orthogonal to the central axis Z is formed at the end which is the lower end side when screwed into the male screw portion 6e.
The planar view shape of the fixed surface 39a is an annular shape having the same size as the fixed portion 5B of the film mold 5.
In the fine structure forming mold 30, the film mold 5 includes the fixing member 39 in a state in which the fixed part 5 </ b> B on the back surface 5 d side is bonded to the fixing surface 39 a and aligned with a plane orthogonal to the central axis Z. It is fixed.
For this reason, the film mold 5 can be attached and detached together with the fixing member 39 by attaching and detaching the fixing member 39 to and from the mold holding member 6.

The film mold 5 fixed to the fixing member 39 may be fixed in a natural state as in the first embodiment, but is applied in an in-plane direction from the natural state by applying an initial tension. It is possible.
The state deformed by applying an initial tension is referred to as an initial deformed state, and the shape of the molding surface portion 5A ′ ″ in the initial deformed state is in the in-plane direction. It has a stretched shape. Further, the apparent bending rigidity of the film mold 5 is increased in accordance with the magnitude of the initial tension.
Thus, in the initial deformation state, the molding surface portion 5A in the natural state changes to the molding surface portion 5A ′ ″. Therefore, when the work surface contact state is formed from the initial deformation state, the shape of the antireflection portion 2 is changed. Can do. For this reason, since the film type 5 can be used also for shaping | molding of the other antireflection part close | similar to the shape of the antireflection part 2, the versatility of the film type 5 improves.
Further, by applying the initial tension, the curvature of the deformed state of the film mold 5 can be easily changed minutely even when the radius of curvature of the work surface is large and close to a plane.

In order to manufacture such a microstructure forming mold 30, as shown in FIG. 15A, the molding surface portion 5A is formed at the center of the sheet member 35 having an outer diameter larger than the outer diameter of the fixed surface 39a. To do.
Next, the outer peripheral portion of the sheet member 35 is pulled radially outward to give a tension T, thereby forming the molding surface portion 5A ″ in an initial deformation state.
Next, as shown in FIG. 15B, the back surface on the outer peripheral side of the molding surface portion 5A ′ ″ of the sheet member 35 is bonded and fixed to the fixing surface 39a of the fixing member 39. After fixing, the fixing surface 39a is fixed. Cut and remove the part protruding outward.
Next, the fixing member 39 to which the film mold 5 ″ ′ is fixed in this manner is screwed and fixed to the male screw portion 6e of the mold holding member 6.
In this way, the microstructure forming mold 30 is manufactured.

[Third Modification]
Next, a surface shape forming method according to a third modification of the present embodiment will be described.
FIG. 16 is a schematic process explanatory view showing a sheet-shaped mold member deformation process of the surface shape forming method of the third modified example of the first embodiment of the present invention.

The surface shape molding method of this modification is a modification of the sheet-shaped member deformation process of the surface shape molding method of the first embodiment.
In the sheet-shaped mold member deformation process of this modification, the film mold 5 is formed of a resin material that is softened by heating, and when the internal pressure of the pressure change chamber P is reduced by the pressure controller 8 as shown in FIG. The heater 40 is disposed below the film mold 5 to heat the film mold 5.
Thereby, since the film type | mold 5 softens, a deformation | transformation becomes easy.

FIG. 16 is a schematic diagram, and the heater 40 is formed in a plate shape, but this is an example, and the shape of the heater 40 is not particularly limited.
Further, the temperature distribution of the heater 40 can be set to an appropriate temperature distribution as required.
For example, the entire surface of the film mold 5 may be heated uniformly, or the degree of softening of the film mold 5 may be changed depending on the location by giving a temperature distribution.
Thus, since the rigidity of the film mold 5 can be partially changed by appropriately adjusting the temperature distribution of the heater 40, even if the internal pressure of the pressure change chamber P is constant, the deformation state before pressing is changed. The shape of the molding surface portion 5A '' can be appropriately transformed into a shape.
For example, since the surface to be processed has an aspherical shape, when it is necessary to make the curvature of the central portion of the molding surface portion 5A ″ larger than the curvature of the outer peripheral portion, the surface of the film mold 5 faces the central portion. By setting the temperature of the heater 40 to be high, the curvature of the central portion of the molding surface portion 5A ′ ″ can be increased.

[Second Embodiment]
Next, a surface shape molding method and a microstructure forming mold according to a second embodiment of the present invention will be described.
FIG. 17 is a schematic configuration diagram of a microstructure forming mold according to the second embodiment of the present invention.

As shown in FIG. 17, the surface processing apparatus 60 used in the surface shape forming method of the present embodiment includes the microstructure forming mold 10, the mold moving unit 7, and the pressure control of the surface processing apparatus 50 of the first embodiment. Instead of the part 8, a microstructure forming mold 70, a mold moving part 77, and a deformation control shaft 78 (sheet-shaped mold member deforming part) are provided.
Hereinafter, a description will be given centering on differences from the first embodiment.

The microstructure forming mold 70 includes a mold holding member 76 instead of the mold holding member 6 of the first embodiment.
The mold holding member 76 includes a through hole 76 d through which the deformation control shaft 78 is inserted instead of the flow hole 6 d of the mold holding member 6. In the present embodiment, the internal space of the mold holding member 76 functions as a space in which the film mold 5 and the deformation control shaft 78 can move, and does not have the function of the pressure change chamber P.

The mold moving unit 77 is provided with an axis moving mechanism 77b in place of the axis moving mechanism 7b in which the pipe line 7c of the mold moving unit 7 of the first embodiment is omitted.
The moving shaft 7a is connected to the upper surface 6f of the mold holding member 76 as in the first embodiment. However, a shaft hole portion 77c that penetrates the hole bottom surface 6b of the mold holding member 76 is provided inside the moving shaft 7a of the present embodiment so that the deformation control shaft 78 is movably inserted along the vertical axis. Yes.
The shaft moving mechanism 77b advances and retracts the moving shaft 7a along the vertical axis in the same manner as the shaft moving mechanism 7b of the first embodiment, and the deformation control shaft 78 extends along the vertical axis independently of the moving shaft 7a. It is something that advances and retreats.

The deformation control shaft 78 is made of a metal shaft member, one end of which is connected to the shaft moving mechanism 77b, and a pressing portion made of an elastic body connected to the other end of the drive shaft 78a. 78b.
The drive shaft 78a is inserted through the shaft hole 77c of the moving shaft 7a, and is supported so as to be able to advance and retract along the vertical axis.
The pressing portion 78b is bonded to the back surface 5d of the film mold 5 fixed to the mold holding member 6 at the lower end.

Next, regarding the surface shape molding method of the present embodiment using the surface processing apparatus 60, the antireflection portion 2 is formed on the lens body 1 as in the first embodiment, and the lens 1A as an optical element is formed. An example in the case of manufacturing will be described.
FIGS. 18A and 18B are schematic process explanatory views showing a sheet-shaped member deformation process and a sheet-shaped mold member pressing process of the surface shape molding method according to the second embodiment of the present invention. .

After the film mold 5 is manufactured, the surface shape molding method of the present embodiment is substantially the same as the first embodiment described above, in the same manner as in the first embodiment, the sheet-shaped mold member arranging step, the sheet-shaped mold member deforming step, and the sheet-shaped mold member moving step. In this method, the sheet-shaped member pressing step, the curing step, and the release step are performed in this order.
Hereinafter, a description will be given centering on differences from the first embodiment.

  The sheet-like mold member arranging step of the present embodiment is the same process as the sheet-like mold member arranging step of the first embodiment.

As shown in FIG. 18A, the sheet-shaped mold member deformation process of the present embodiment drives the deformation control shaft 78 to form the film mold 5 ″ in a deformed state before pressing. Different from the embodiment.
That is, an operation control unit (not shown) drives the shaft moving mechanism 77 b of the mold moving unit 77 to raise the deformation control shaft 78. As a result, the pressing portion 78b at the lower end of the deformation control shaft 78 is pulled up, and the central portion of the film mold 5 bonded to the pressing portion 78b is pulled upward, whereby the film mold 5 is deformed and the film mold 5 ''. Is formed.
In the present embodiment, since the external force acting on the film mold 5 acts from the pressing portion 78b, the surface 5c '' does not have the same shape as in the first embodiment, but the center-separated curved shape, the peripheral edge separation Mold curved shapes are possible.

Next, the sheet-shaped member moving process of this embodiment is performed.
In this step, an operation control unit (not shown) drives the shaft moving mechanism 77b of the mold moving unit 77 to fix the mold holding member 76 in a state where the position of the deformation control shaft 78 is fixed to the mold holding member 76. Lower. The position where the mold holding member 76 is lowered is the same as in the first embodiment.

Next, as shown in FIG. 18B, the sheet-like mold member pressing step of this embodiment is performed.
In this step, an operation control unit (not shown) drives the shaft moving mechanism 77b of the mold moving unit 77, fixes the position of the mold holding member 76, and lowers only the deformation control shaft 78.
Thereby, the surface 5c '' in the deformed state before pressing is deformed into the surface 5c 'in the work surface contact deformation state, and the surface 5c' is in close contact with the convex lens surface 1a.
Further, when the deformation control shaft 78 is lowered, the pressing portion 78 b is compressed, and a pressing force is transmitted to the back surface 5 d of the central portion of the film mold 5. This pressing force is applied to push the UV curable resin 20 sandwiched between the surface 5c '' and the central portion of the convex lens surface 1a to the outer peripheral side and to ensure that the surface 5c ′ and the convex lens surface 1a are in close contact with each other. Therefore, the amount of lowering of the deformation control shaft 78 is controlled so that a pressing force is applied so that the shape accuracy of the molding surface portion 5A ′ does not deteriorate in consideration of the elastic coefficient of the pressing portion 78b.
In such a pressing process, external force does not act on the back surface 5d that is not in contact with the pressing portion 78b. However, in the deformed state before pressing, since the film mold 5 ″ is stretched in the in-plane direction with respect to the natural molding surface portion 5A, even if the deformation control shaft 78 is lowered, the film mold 5 ″ Shrink in the in-plane direction by elastic restoring force. Therefore, the formation of the surface 5c ′ is not hindered.

The curing process of this embodiment performed next is the same process as that of the first embodiment.
Next, the mold release process of this embodiment is performed. In this step, an operation control unit (not shown) drives the shaft moving mechanism 77 b of the mold moving unit 77 to raise the mold holding member 76 and lower the deformation control shaft 78 with respect to the mold holding member 76. Thus, only the mold holding member 76 is raised in a state where the positional relationship of the deformation control shaft 78 with respect to the convex lens surface 1a is held.
Thereby, since the film mold 5 fixed to the mold holding member 76 is in a state of relatively projecting downward, the antireflection part 2 formed in the curing step is performed in the same manner as in the first embodiment. The mold release proceeds from the outer peripheral side toward the center side.
When the mold release proceeds to the outer peripheral side of the pressing portion 78b, the shaft moving mechanism 77b raises the deformation control shaft 78 together with the mold holding member 76, thereby completely releasing the surface of the convex lens surface 1a.
As a result, in this embodiment, as in the first embodiment, the protrusion 2a can be released without being deformed or damaged.

  In the above description of each embodiment and each modification, as an example, the case where the workpiece is an optical element substrate and the optical surface that is the workpiece surface is a convex spherical surface or a concave spherical surface is described. However, the workpiece is not limited to the optical element substrate, and the workpiece surface is not limited to a spherical surface, for example, an axially symmetric aspherical surface, a spheroidal surface, an anamorphic surface, a free-form surface, etc. But you can.

  Further, in the description of each of the above embodiments and modifications, an example in which the optical element substrate is a lens has been described. However, the optical element manufactured by the surface shape molding method of the present invention is limited to a lens. Not. For example, an optical element such as a mirror, a prism, or a filter may be used.

  In the description of each of the above embodiments and modifications, the example in the case where the fine structure is the antireflection portion 2 formed by the conical protrusion 2a has been described. However, in order to form the antireflection structure, the lens surface As long as it has a shape in which the refractive index changes in the vicinity, the shape is not limited to a conical shape, and a pyramid shape such as a triangular pyramid shape or a quadrangular pyramid shape can be suitably employed.

In the description of each of the above embodiments and modifications, the example in the case where the microstructure is an antireflection structure has been described. However, if the microstructure is an uneven shape formed by nanoimprint technology, It is not limited, For example, uneven | corrugated shapes, such as a cylinder, a cylindrical hole, the hole shape which the weight body reversed, and a bell shape, are employable.
For this reason, the fine structure is not limited to the antireflection structure.

In the description of each of the embodiments and the modifications described above, the UV light source 4 of the surface processing apparatus has been described as an example in which the lens 1A is disposed on the side opposite to the microstructure forming mold. It is possible to form the holding member and the sheet-shaped mold member with a light-transmitting material, and to place the UV light source 4 at a position where UV light can be irradiated through the holding member and the sheet-shaped mold member.
For example, the UV light source 4 may be disposed inside the mold holding member 6 and irradiated with UV light from the back surface 5d side of the film mold 5.

In the above description of each embodiment and each modification, an example in which the optical element substrate is fixed and the microstructure forming mold is moved has been described. However, the moving shaft 7a is replaced with a fixed shaft, and the holding unit 3 is replaced. A moving mechanism for advancing and retreating the substrate with respect to the microstructure forming mold may be provided.
Moreover, it is good also as a structure which supports the mold for fine structure formation, and the holding | maintenance part 3 so that each can move, and both move.

In the description of the second embodiment, an example in which only one deformation control shaft 78 is provided at the center of the film mold 5 has been described. However, this is an example, and the deformation control shaft 78 is It is possible to arrange them at an appropriate position, and it is possible to provide an appropriate number of two or more.
As described above, by providing the plurality of deformation control shafts 78, the curved shape in the deformed state before pressing can be controlled more finely, so that it is possible to deal with more various shapes of the work surface.

  In the description of the first embodiment, an example in which air pressure is used to change the internal pressure of the pressure change chamber P has been described. However, the pressure is adjusted by filling the pressure change chamber P with a liquid fluid. However, a configuration in which the film mold 5 is deformed is also possible.

  In the description of the second embodiment, the example in which the film mold 5 is fixed so as to close the opening 6a of the mold holding member 76 has been described. However, in the second embodiment, a pressure change chamber is formed. Therefore, the film mold 5 may have a shape in which a part of the outer periphery is fixed to the mold holding member 76.

In addition, all the constituent elements described in the above embodiment and each modification can be implemented by being appropriately combined or deleted within the scope of the technical idea of the present invention.
For example, when the film mold 5 is fixed by being sandwiched between the mold holding member 6 and the fixing member 9 as in the first embodiment, the film mold 5 is stretched and the initial deformation is performed as in the second modification. It may be fixed after the state.
Further, for example, the heater 40 of the third modification may be used together when forming the initial deformation state of the second modification.

1,21 Lens body (workpiece, optical element substrate)
1A, 21A Lens (optical element)
1a, 1b Convex lens surface (surface to be processed, curved optical surface)
2 Antireflection part (fine structure, antireflection structure)
2a Protrusion (weight)
3 Holding unit 4 UV light source 5, 5 ′, 5 ″, 5 ′ ″ film type (sheet-like mold member)
5A, 5A ′, 5A ″, 5A ′ ″ Molded surface portion 5B Fixed portion 5a, 5a ′, 5a ″ Recessed hole portion 5c, 5c ′, 5c ″, 5c ′ ″ Surface 6, 76 Type holding member 6a opening 6e inner wall surface 7, 77 type moving part 8 pressure control part (sheet-like mold member deformation part)
9, 39 Fixed member 10, 20, 70 Microstructure forming mold 20 UV curable resin (molding material)
21a Concave lens surface (surface to be processed, curved optical surface)
40 Heater 50, 60 Surface processing device 78 Deformation control shaft (sheet-shaped member deforming portion)
C, Z Center axis N Normal O Optical axis P Pressure change chamber S Gap

Claims (8)

A surface shape forming method for forming a fine structure having a plurality of concave and convex shapes on a curved work surface of a work piece,
A sheet-like mold member formed of a sheet-like elastic body, having the plurality of concave and convex shapes reversed on one surface and rearranged, and formed into a shape compressed in the in-plane direction of the one surface, is formed at one end. A sheet-like mold member arranging step of arranging the mold holding member having an opening so as to cross the opening;
A sheet-shaped mold member deformation step of extending the sheet-shaped mold member in a region which is an inner peripheral side of the opening and bending and deforming according to the curved shape of the surface to be processed;
A sheet-shaped mold member moving step for moving the curved sheet-shaped member relative to a position close to the workpiece surface after disposing a liquid molding material on the workpiece surface;
A sheet-shaped mold member pressing step of pressing the one surface against the processing surface by pressing the sheet-shaped mold member adjacent to the processing surface from the surface opposite to the one surface;
A curing step of curing the molding material sandwiched between the sheet-shaped mold member and the work surface;
A mold release step of separating the sheet-shaped mold member from the work surface after the molding material is cured;
A method of forming a surface shape, comprising: In the sheet-shaped member deformation process,
The sheet-shaped mold member is curvedly deformed by changing a pressure inside the mold holding member in a state where the opening is closed by the sheet-shaped mold member. Surface shape molding method. In the sheet-shaped member deformation process,
The curved shape of the sheet-shaped mold member is such that when the curved sheet-shaped mold member is brought into contact with the outer edge of the surface to be processed, the tip of the one surface of the curved sheet-shaped member 3. The surface shape molding method according to claim 1, wherein the envelope surface and the surface to be processed are separated from each other except for the contact portion. In the sheet-shaped member deformation process,
The curved sheet-like member has a shape in which a gap that gradually increases from the outer edge side toward the center side is formed between the envelope surface at the tip of the one surface of the curved sheet-like member and the processed surface. The surface shape forming method according to claim 3. The workpiece is an optical element substrate having a curved optical surface as a workpiece surface,
The surface shape forming method according to claim 1, wherein the microstructure is an antireflection structure in which weights are gathered. A microstructure forming mold for forming a microstructure having a plurality of irregularities on a curved work surface,
A sheet-like mold member formed of a sheet-like elastic body, in which the plurality of concave-convex shapes are reversed and rearranged on one surface, and a shape compressed in the in-plane direction of the one surface is formed;
A mold holding member having an opening at one end and arranging the sheet-like member so as to cross the opening;
A sheet-shaped member deforming portion that stretches the sheet-shaped mold member in a region on the inner peripheral side of the opening and bends and deforms in accordance with the curved shape of the processing surface;
A mold for forming a fine structure, comprising: The sheet-shaped member deforming portion is
The sheet-shaped mold member is curvedly deformed by changing a pressure inside the mold holding member in a state where the opening is closed by the sheet-shaped mold member. Microstructure forming mold. An optical element comprising a step of forming the microstructure on the optical surface of an optical substrate having a curved optical surface using the microstructure forming mold according to claim 6 or 7. Manufacturing method.

Images