JP2009294600A - Molded body and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded body giving a sharp diffraction spot with high diffraction efficiency and a manufacturing method or the like thereof. <P>SOLUTION: The molded body has a phase separation structure provided with a matrix 2 comprising a photopolymerizable composition and a plurality of columnar structural body 4 arranged in the matrix, having a refractive index different from that of the matrix, comprising a photopolymerizable composition and having a circular or polygonal cross-section and has an ruggedness 6 synchronized with the phase separation structure and having a height of ≥10 nm and <1 μm at least on the one side surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a molded body and a method for producing the same, and more particularly to a molded body such as an optical film used as an optical article having optical properties such as diffraction, polarized light, and diffusion, and a method for producing the same.

  Since there are many kinds of polymer materials that can be selected and various functions can be exhibited, attempts to apply the polymer materials to optical applications have been actively made in recent years. For example, it is conceivable to use a molded body of a polymer material in which a one-dimensional or two-dimensional microstructure is formed as a light control element or a light diffraction element.

  As such a molded body, a polymer film having a phase separation structure in which a large number of structures different in refractive index from the matrix are oriented in the same direction is known in a matrix of a polymer material (Patent Document 1). To 3). In the polymer film having such a phase separation structure, when light is incident in parallel to the axial direction of the structure, a diffraction spot is given due to the arrangement of the structure. Therefore, such a polymer film can be used as an optical diffraction element that diffracts incident light to a specific position with a predetermined intensity.

  Patent Document 1 describes a film having such a structure and a manufacturing method thereof. In the method of Patent Document 1, a film having such a structure is produced by irradiating a photopolymerizable composition having a certain film thickness with light from a linear light source from a predetermined angle to cause polymerization. The film thus produced selectively diffracts incident light having a specific incident angle.

Patent Document 2 describes a film having a sea-island phase separation structure. In this film, a columnar island structure is formed so as to extend in the film thickness direction in the sea structure.
In this method for producing a film, first, a photopolymerizable composition is applied to a coating surface with a uniform thickness, and the surface is covered with a mask in which a large number of perforations for forming an island structure are randomly patterned. Next, the surface of the photopolymerizable composition is irradiated with ultraviolet light through this mask to form a columnar body having an island structure inside the photopolymerizable composition. And after forming a columnar body, a mask is removed, and an ultraviolet-ray is further irradiated, a sea structure part is hardened, and a film is completed.

In Patent Document 3, an assembly of a plurality of columnar structures is randomly formed in the film thickness direction, and unevenness having a height of 1.0 μm or more and 5.0 μm or less is formed on at least one surface of the resin layer. An isotropic diffusion medium and a method for its production are described.
Also in this film production method, the photopolymerizable composition injected into the mold is cured by irradiation with parallel light.

JP-A-3-284702 JP 11-287906 A JP 2005-292217 A

  The film described in Patent Document 1 has a strip-like phase separation structure parallel to each other, and functions as a light control element that changes light transmittance according to an incident angle, but as a light diffraction element, it is one-dimensional. Therefore, the incident light cannot be diffracted with high efficiency, or a diffraction spot showing a steep angular spectrum cannot be given.

  Moreover, since the film of patent document 2 is what disperse | transmits and permeate | transmits light with the sea island structure without regularity, it was not able to give a sharp diffraction point.

Here, it is known that the light passing through the opening has a spread due to diffraction.
When a plane wave having a wavelength λ is incident on a circular aperture of radius a, the intensity I at the image plane after diffraction is as follows when the image plane is a distance L from the aperture and the distance from the center on the image plane is r. It is calculated by the following formula.
I = (πa ² ) 2 [2J ₁ (R) / R] ² (1)
(R = 2πar / λL)

The distance r _min at which the diffracted light intensity first exhibits a minimum value on the image plane is obtained as the first zero of J ₁ (R), that is, r when R = 3.83. Of the total amount, energy of about 84% are known to be concentrated in the circle of r _min and the radius, r _min is a measure of the spread of the diffracted light from the circular opening.

For example, when light having a wavelength of 365 nm passes through a circular opening with a = 1 μm, L _min = 5 μm with L = 45 μm. This indicates that light that has passed through a circular opening having a radius of 1 μm spreads (blurs) into a circle having a radius of 5 μm as it travels 45 μm. As a result, it becomes difficult to form a columnar structure having a high aspect ratio and a radius of 1 μm only by irradiation through a photomask.

  Patent Document 2 shows an example in which an island structure is formed using a photomask. However, since the diffraction of light is not considered, the method of Patent Document 2 cannot form a columnar structure with a high aspect ratio. it is conceivable that. That is, the method described in Patent Document 2 cannot produce a film that diffracts light into a predetermined pattern with high diffraction efficiency.

  In the film described in Patent Document 3, an assembly of a plurality of columnar structures is randomly formed in the film thickness direction, and irregularities having a height of 1.0 μm or more and 5.0 μm or less are formed on at least one surface of the resin layer. Has been. However, since the columnar structure is randomly formed in the film described in Patent Document 3 and light is diffused by surface irregularities, the light cannot be diffracted into a predetermined pattern with high diffraction efficiency.

  As described above, the conventional method cannot produce a polymer film that gives a sharp diffraction spot with high diffraction efficiency by photopolymerization. Therefore, the above-described conventional polymer film cannot be used as an optical low-pass filter or the like that requires an optical diffraction plate that diffracts light into a predetermined pattern with high diffraction efficiency.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a molded body that provides a sharp diffraction spot with high diffraction efficiency, a method for manufacturing the same, and the like.

According to the present invention,
A phase separation comprising: a matrix made of a photopolymerizable composition; and a plurality of columnar structures that are arranged in the matrix and have a circular or polygonal cross section made of a photopolymerizable composition that has a refractive index different from that of the matrix. A molded body having a structure,
At least one side surface has irregularities with a height of 10 nm or more and less than 1 μm synchronized with the phase separation structure;
There is provided a molded body characterized by the above.

  According to such a configuration, it is possible to give a sharp diffraction spot with high diffraction efficiency by the unevenness synchronized with the phase separation structure.

According to a preferred embodiment of the present invention, each of the columnar structures is oriented in substantially the same direction and is arranged in a regular lattice shape on a plane perpendicular to the orientation direction.
According to another preferred aspect of the present invention, the columnar structure has substantially the same cross-sectional shape perpendicular to the orientation direction.
According to another preferred embodiment of the present invention, the columnar structure has an aspect ratio of 10 or more.
According to another preferred embodiment of the present invention, the photopolymerizable composition is an acrylic photopolymerizable composition.

  According to another aspect of the present invention, there is provided an optical low-pass filter configured using the molded body.

According to another aspect of the invention,
A phase separation structure comprising a matrix made of a photopolymerizable composition, and a plurality of columnar structures having a circular or polygonal cross section made of the photopolymerizable composition and having a refractive index different from that of the matrix. And a method for producing a molded body having irregularities synchronized with the phase separation structure on at least one surface,
Applying a photopolymerizable composition containing a photocurable monomer or oligomer and a photopolymerization initiator on a substrate;
A step of arranging a photomask having a light passage region and a light non-passage region between the light source and the base material on which the photocurable resin is disposed;
The photopolymerizable composition is irradiated from the light source with parallel light having a full width at half maximum of 100 nm or less and a substantially constant light intensity distribution toward the photopolymerizable composition on the substrate through the photomask. A first light irradiation step of curing a portion irradiated with parallel light to an incompletely cured state,
The photomask is removed, and the photopolymerizable composition on the substrate is irradiated with parallel light having a full width at half maximum of 100 nm or less and a substantially constant light intensity distribution toward the photopolymerizable composition. A second light irradiation step for completing the curing,
The manufacturing method of the molded object characterized by this is provided.

According to another preferred embodiment of the present invention, in the first light irradiation step and the second light irradiation step, the photopolymerizable composition applied on the substrate is subjected to parallel light in an inert gas atmosphere. Irradiate.
According to another preferred embodiment of the present invention, in the first light irradiation step, a portion irradiated with parallel light in the photopolymerizable composition is cured to a curing degree of 10% or more and 80% or less.
According to another preferred aspect of the present invention, in the photomask, a large number of the light passage areas are arranged in a regular lattice pattern in the light non-passage area.

Hereinafter, the structure of the molded object of preferable embodiment of this invention is demonstrated.
FIG. 1 is a perspective view of a part of a molded body 1 schematically showing the configuration of the molded body 1 according to a preferred embodiment of the present invention.
As shown in FIG. 1, a molded body 1 includes a matrix 2 which is a thin plate-like substrate made of a photopolymerizable composition, and a photopolymerizable composition regularly arranged in the matrix 2. And a large number of columnar structures 4.

  The matrix 1 has a substantially uniform thickness in the range of about 10 μm to 500 μm. The columnar structure 2 has a refractive index different from that of the matrix 1. The cross-sectional pattern of the columnar structure 2 and the size, pitch, and shape of the cross-sectional diameter are not particularly defined. When the cross-section of the columnar structure 2 is a perfect circle, the diameter of the circle is 80 nm to 20 μm. Is preferable, more preferably 1 μm to 10 μm, and the pitch is preferably 120 nm to 30 μm, and more preferably 2 μm to 20 μm.

  Each columnar structure 4 has substantially the same shape, and its axis extends through the thin plate (film) -shaped molded body 1 in the thickness direction and has an aspect ratio of 10 or more. In detail, the columnar structure 4 has a cylindrical shape whose cross-sectional shape in the axial direction is substantially constant, and is oriented so that the axial lines are in the same direction, that is, substantially parallel to each other. Is arranged.

In this embodiment, the columnar structure 4 is oriented such that its orientation direction (axial direction) is substantially the same as the thickness direction of the shaped body 1, but with respect to the thickness direction of the shaped body 1. May be oriented at a predetermined angle.
In addition, the columnar structure 4 of the present embodiment has a circular or polygonal column shape in cross section, but is not limited thereto, and may be other columnar shapes such as a rectangular column or a plate. In addition, the circle in the cross section of the columnar structure 4 includes a true circle and an ellipse. Moreover, the polygon in the cross section of the columnar structure 4 includes a strip shape, a strip shape, a herringbone pattern, and the like.

  Further, the plurality of columnar structures 3 are arranged in a regular triangular lattice shape, but may be arranged in other regular patterns, for example, in any other lattice shape such as a square lattice. It may be arranged.

  The molded body 1 further includes unevenness 6 of 10 nm or more and less than 1 μm synchronized with the phase separation structure inside the molded body on one surface of the matrix 1. The height of the irregularities 6 is preferably 20 nm or more and less than 500 nm, and more preferably 50 nm or more and less than 250 nm. As a specific arrangement of the irregularities 6, convex portions are located on the surface layer (on the end face) of the columnar structure 4.

  The shape of the molded body of the present invention is suitably a film shape having a uniform thickness that is generally used when used for optical applications. However, the shape of the molded body of the present invention is appropriately set according to its use, and is not limited to a film shape having a uniform thickness, but other shapes such as a thickness in the length direction. Different shapes may be used.

  In the molded body 1 having such a configuration, when light is incident on the molded body 1 from the main surface direction, the columnar structure 4 and the arrangement of the columnar structure 4 inside the molded body formed on at least one surface thereof are synchronized. Due to the arrangement of the irregularities 6, the molded body 1 gives a diffraction spot and functions as an optical diffraction element.

Next, the manufacturing method of the molded object 1 is demonstrated.
2 and 3 are a plan view and a cross-sectional view showing a manufacturing process of the molded body 1, respectively.
In order to manufacture the molded body 1, first, the photopolymerizable composition 10 is applied to the substrate 8 with a uniform thickness, and then the photopolymerizable composition is applied to the irradiation light source (not shown) and the substrate 8. A photomask 12 is arranged between the two. Thereafter, light is irradiated from the irradiation light source toward the photopolymerizable composition 10 applied onto the substrate 8 through the photomask 12 to cure the photopolymerizable composition 10.

  Next, the photomask is removed, and further irradiated with light from the irradiation light source toward the photopolymerizable composition coated on the substrate, photopolymerization of the photopolymerizable composition is completed, and integrated on the substrate, And the molded object 1 transparent with respect to a use wavelength can be obtained. Moreover, the molded object 1 transparent with respect to a use wavelength can be obtained by peeling from the base material the photopolymerizable composition in which this photopolymerization was completed.

Hereinafter, the manufacturing method of the molded object 1 is demonstrated in detail.
(Application of photopolymerizable composition on substrate)
The base material 8 is a plate-like member having a smooth surface. The substrate 8 is formed of soda glass, quartz glass, Pyrex (registered trademark) glass, silicon wafer, plastic film, plastic plate or the like.

  Examples of the method for applying the photopolymerizable composition 10 onto the substrate include a method using a bar coater, a slit die coater, a spin coater, a circular coater, a gravure coater, a CAP coater and the like. In addition, since a photomask is disposed on the photopolymerizable composition 10 during light irradiation, it is important that the surface of the applied photopolymerizable composition is flat and that there is no bulge at the end.

Below, the material which can be used for a photopolymerizable composition is demonstrated.
(Polyfunctional monomer)
It is preferable that a polyfunctional monomer is contained in the photopolymerizable composition. As such a polyfunctional monomer, a (meth) acryl monomer containing a (meth) acryloyl group, a monomer containing a vinyl group, an allyl group, or the like is particularly preferable.

  Specific examples of the polyfunctional monomer include triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6 -Hexanediol di (meth) acrylate, hydrogenated dicyclopentadienyl di (meth) acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Tetramethylolmethane tetra (meth) acrylate, pentaerythritol hexa (meth) acrylate, polyfunctional epoxy (meth) acrylate, polyfunctional urethane (meth) acrylate, divinylbenzene, toluene Examples include allyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl chlorendate, N, N′-m-phenylenebismaleimide, diallyl phthalate, and the like. These may be used alone or as a mixture of two or more. can do.

  A polyfunctional monomer having three or more polymerizable carbon-carbon double bonds in the molecule is preferable because the density of the crosslink density due to the difference in the degree of polymerization is likely to increase and a columnar structure is easily formed.

  Particularly preferred polyfunctional monomers having three or more polymerizable carbon-carbon double bonds are trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, penta There is erythritol hexa (meth) acrylate.

  When two or more kinds of polyfunctional monomers or oligomers thereof are used as the photopolymerizable composition, it is preferable to use those having different refractive indexes when the respective homopolymers are used. It is more preferable to combine large ones.

  In order to obtain functions such as diffraction, deflection, and diffusion with high efficiency in the molded body 1, it is necessary to increase the refractive index difference between the matrix and the columnar structure, and the refractive index difference is 0. Is preferably 0.01 or more, and more preferably 0.05 or more. Further, since the difference in refractive index is increased by the diffusion of the monomer during the polymerization process, a combination having a large difference in diffusion constant is preferable.

  In addition, when using 3 or more types of polyfunctional monomers or oligomers, the refractive index difference between at least any two of the respective homopolymers may be within the above range. In addition, the two monomers or oligomers having the largest refractive index difference of the homopolymer should be used in a weight ratio of 10:90 to 90:10 in order to obtain highly efficient functions such as diffraction, deflection, and diffusion. Is preferred.

(Monofunctional monomer)
In the photopolymerizable composition, a monofunctional monomer or oligomer having one polymerizable carbon-carbon double bond in the molecule may be used together with the polyfunctional monomer or oligomer as described above. As such a monofunctional monomer or oligomer, those containing a (meth) acryl monomer containing a (meth) acryloyl group, a vinyl group, an allyl group or the like are particularly preferable.

  Specific examples of the monofunctional monomer include, for example, methyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ethyl carbitol (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, phenyl Carbitol (meth) acrylate, nonylphenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, (meth) acryloyloxyethyl succinate, (meth) acryloyloxyethyl phthalate, phenyl (meth) acrylate , Cyanoethyl (meth) acrylate, Tribromophenyl (meth) acrylate, Phenoxyethyl (meth) acrylate, Tribromophenoxyethyl (meth) acrylate, Ben (Meth) acrylate, p-bromobenzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) ) (Meth) acrylate compounds such as acrylates; vinyl compounds such as styrene, p-chlorostyrene, vinyl acetate, acrylonitrile, N-vinylpyrrolidone, vinylnaphthalene; allyl compounds such as ethylene glycol bisallyl carbonate, diallyl phthalate, diallyl isophthalate Etc.

  These monofunctional monomers or oligomers are used for imparting flexibility to the molded article 1, and the amount used thereof is preferably in the range of 10 to 99% by mass of the total amount with the polyfunctional monomers or oligomers, and 10 to 50% by mass. % Range is more preferred.

(Polymer, low molecular weight compound)
The photopolymerizable composition may also be a homogeneous solution mixture containing the polyfunctional monomer or oligomer and a compound having no polymerizable carbon-carbon double bond.
Examples of the compound having no polymerizable carbon-carbon double bond include polymers such as polystyrene, polymethyl methacrylate, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, and nylon, toluene, n-hexane, cyclohexane, acetone, and methyl ethyl ketone. , Low molecular weight compounds such as methyl alcohol, ethyl alcohol, ethyl acetate, acetonitrile, dimethylacetamide, dimethylformamide, and tetrahydrofuran, organic halogen compounds, organosilicon compounds, plasticizers, additives such as stabilizers, and the like.

  These compounds having no polymerizable carbon-carbon double bond are used for adjusting the viscosity of the photopolymerizable composition to improve the handleability when the molded body 1 is produced, and for the monomer component in the photopolymerizable composition. It is used to improve the curability by lowering the ratio, and the amount used is preferably in the range of 1 to 99% by mass of the total amount with the polyfunctional monomer or oligomer, and the handling property is also good while being ruled. In order to form a columnar structure having a typical arrangement, the range of 1 to 50% by mass is more preferable.

(Initiator)
The photopolymerization initiator used in the photopolymerizable composition is not particularly limited as long as it is used in normal photopolymerization in which polymerization is performed by irradiating active energy rays such as ultraviolet rays. For example, benzophenone , Benzyl, Michler's ketone, 2-chlorothioxanthone, benzoin ethyl ether, diethoxyacetophenone, pt-butyltrichloroacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropylphenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl -2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, dibenzosuberone and the like.
The amount of these photopolymerization initiators used is preferably in the range of 0.001 to 10% by mass relative to the weight of the other photopolymerizable composition, so as not to deteriorate the transparency of the molded product 1. More preferably, the content is 0.01 to 5% by mass.

(Photomask)
In the molded body 1 shown in FIG. 1, a plurality of columnar structures 4 having a refractive index different from that of the matrix 2 are oriented in the same direction in the matrix 2, and the phase separation inside the molded body is formed on at least one side surface thereof. It has unevenness 6 that is in sync with the structure.
Further, the columnar structures 4 are arranged in a triangular lattice pattern in a plane perpendicular to the alignment direction of the columnar structures 4, and this pattern can be arbitrarily determined by texturing with the photomask 12.

  In the present embodiment, texturing is used as a method for determining the arrangement of the projections and depressions 6 in synchronization with the columnar structures 4 having different refractive indexes and the phase separation structure inside the molded body formed on at least one surface thereof. The texturing described here is a method in which positional information is input in advance to give the regular structure formed a high regularity.

  By texturing with a photomask, the columnar structure 4 can be penetrated from the parallel light irradiation surface to the substrate, and as a result, at least one surface of the molded body has unevenness 6 synchronized with the phase separation structure inside the molded body. Form.

  As the photomask 12, those used in the photolithography method can be used. Further, the mask hole pattern and the size, pitch, and shape of the hole diameter are not particularly defined, but when the mask hole is a circular hole, the hole diameter is preferably 80 nm to 20 μm, more preferably 1 μm to 10 μm, The pitch is preferably 120 nm to 30 μm, more preferably 2 μm to 20 μm.

  Similarly, when the mask holes are striped, the hole width is preferably 80 nm to 20 μm, more preferably 1 μm to 10 μm, and the pitch is preferably 120 nm to 30 μm, more preferably 2 μm to 20 μm.

  In order to manufacture the molded body 1 of this embodiment in which the columnar structures are arranged in a triangular lattice pattern, a photo shown in FIG. 4 in which circular mask holes 14 are regularly arranged in a triangular lattice pattern. A mask 12 is used.

  When the columnar structures are arranged in a square lattice pattern, a photomask 18 in which mask holes 14 are regularly arranged in a square lattice pattern as shown in FIG. 5 is used.

  The shape of the mask hole is not limited to a circle, and may be a polygon such as a triangle, a quadrangle, a hexagon, or an octagon.

  In this embodiment, texturing using a photomask is used to form the columnar structures 4, but the present invention is not limited to this, and laser light, X-rays, γ rays, etc. in the visible or ultraviolet wavelength band are used. The position information may be input by scanning with the radiation.

(Irradiation light source)
As the irradiation light source, one capable of irradiating parallel light such as ultraviolet rays to the photocurable polymer coated on the substrate is used. The parallelism of the irradiated light is preferably such that the spread angle is ± 0.03 rad or less, and more preferably ± 0.001 rad or less.

  In addition to being able to irradiate parallel light, an irradiation light source that can make the light intensity distribution of parallel light substantially constant within a vertical cross section with respect to the traveling direction of the parallel light to be irradiated is used. Specifically, as the irradiation light source, light from a point light source or a rod-shaped light source is converted into parallel light having a substantially uniform light intensity distribution (hat distribution) by a mirror or a lens, a planar light source such as a VCSEL, or the like Can be used.

  Laser light is a preferable light source in terms of parallelism, but its light intensity distribution has a Gaussian distribution, so that it can be used with a substantially uniform light intensity distribution using an appropriate filter or the like. preferable.

  That is, in the molded body 1, in order to arrange the columnar structures 4 and the irregularities 6 formed on at least one surface thereof in synchronization with the arrangement of the columnar structures 4 with high regularity, the film thickness direction B of the molded body 1 It is necessary to proceed the polymerization reaction uniformly in a plane perpendicular to the surface. For this reason, the irradiation light source makes the light intensity distribution substantially uniform in the irradiation range.

The irradiation light source divides the irradiation area into a plurality of areas (9 areas in the present embodiment), measures the light intensity of each area, and the value of the illuminance distribution given by equation (1) is 2.0% The following are used. More preferably, 1.0% or less is used.
Illuminance distribution = (maximum value−minimum value) / (maximum value + minimum value) × 100 (1)

(Light irradiation)
In the manufacturing method of the molded body 1, light irradiation is performed by two light irradiation steps including a first light irradiation step and a second light irradiation step.

(First light irradiation step)
In the first light irradiation step, first, as shown in FIGS. 2 and 3, on the upper part of the photopolymerizable composition applied on the substrate (that is, between the photopolymerizable composition and the irradiation light source), The columnar structure 4 and a photomask 12 for determining the formation position of the irregularities 6 formed on at least one surface of the columnar structure 4 in synchronization with the arrangement of the columnar structure 4 are arranged.

  At this time, the photomask 12 is disposed substantially parallel to the base 8 and the upper surface of the photopolymerizable composition 10 applied on the base 8. In order to control the circular diameter and pitch of the columnar structure more precisely, it is preferable to set the gap between the upper surface of the photopolymerizable composition 10 applied on the substrate and the photomask 12 to 50 μm to 300 μm.

  In the method of determining the formation position using the photomask 12, it is necessary to pay attention to the point that ultraviolet light is diffracted at the mask opening. Due to diffraction, the formation position may be determined in a pattern different from the photomask, or the formation position cannot be determined because the pattern deteriorates too much, so the distance between the photomask and the photopolymerizable composition can be accurately determined. Must be determined.

  In the first light irradiation step, it is desirable that the photopolymerizable composition is placed in an inert gas atmosphere. The photopolymerizable composition may be placed in an inert gas atmosphere either before or after the photomask is placed. However, under conditions where oxygen remains above a certain level, there is a high possibility that poor curing will occur on the surface. Examples of the inert gas used include nitrogen, argon, helium, carbon dioxide and the like. However, the purpose of using the inert gas is to expel oxygen, and any gas can be used as long as it has a composition not containing oxygen.

  In the state where the photomask 12 is arranged and the photopolymerizable composition 1 is placed in an inert gas atmosphere, the full width at half maximum of wavelength is 100 nm or less from the irradiation light source to the irradiation target range and the light intensity distribution is substantially constant. Irradiate parallel light such as ultraviolet rays. Thereby, the parallel light which passed the photomask is irradiated to a photopolymerizable composition with a predetermined pattern.

  In this way, in the first light irradiation step, light such as ultraviolet rays is irradiated as parallel light until the parallel light irradiation site of the photopolymerizable composition is cured in a gel state, and the columnar structure 4 inside the molded body 1. And the formation position of the unevenness | corrugation 6 synchronized with the phase-separation structure inside the molded object formed in the at least one surface is defined.

  Specifically, in the first light irradiation step, regularity between the columnar structure 4 of the molded body 1 to be manufactured and the unevenness 6 synchronized with the phase separation structure inside the molded body formed on at least one surface thereof; In order to achieve both high diffraction efficiency, the photopolymerizable composition is irradiated until the curing degree is in the range of 10% to 80%, more preferably in the range of 20% to 60%.

  In the present embodiment, a state in which the photopolymerizable composition completely reacts and does not generate further heat even when irradiated with light is set to a curing rate of 100% by the optical DSC method. In the first light irradiation step, a predetermined amount is applied to the photopolymerizable composition until the curing rate calculated from the amount of heat generated by the optical DSC method reaches a predetermined degree of curing (10% to 80%). Irradiate the light.

(Second light irradiation step)
Following the first light irradiation step, in the second light irradiation step, the photomask is removed, and parallel light having a half-width of the full wavelength of 100 nm or less and a substantially uniform light intensity distribution is applied to the photopolymerizable composition on the equipment. Irradiate an object.

  Thereby, parallel light is irradiated to the whole photopolymerizable composition, the columnar structure 4 in which the formation position was determined in the first light irradiation step, and the molded body 1 inside formed on at least one side surface of the molded body 1. The phase separation structure consisting of the formation part of the unevenness 6 in synchronization with the columnar structure of this and the other matrix 2 formation part is formed in the film thickness direction, and the refractive index difference between the matrix 2 and the plurality of columnar structures 4 The curing of the photopolymerizable composition 20 is completely terminated while increasing the thickness.

  At this time, the columnar structure 4 is formed in the photopolymerizable composition by parallel light as a clear columnar structure in the matrix 2 so as not to extend in the plane direction and to extend in parallel to the film thickness direction. .

  As a result, the molded body 1 is formed so that the change in refractive index clearly appears at the boundary between the matrix 2 and the columnar structure 4. At the same time, irregularities 6 synchronized with the phase separation structure inside the molded body are formed on at least one surface of the molded body 1 in a form that is induced by the curing shrinkage in the columnar phase separation structure inside the molded body 1. The molded body 1 is manufactured by peeling the completely cured photopolymerization composition from the substrate. In the molded body 1 produced by the method of this embodiment, irregularities are observed on both the irradiation surface side and the substrate surface side.

In general, the resolution when light emitted from a point light source such as a high-pressure mercury lamp is exposed to a photomask by adjusting the uniformity and parallelism of illuminance by a mirror or lens is as follows. When the slit width of the photomask is a and the gap is L, the light passing through the slit is approximated by Fresnel diffraction when the size of a cannot be ignored with respect to L (when the values of a and L are close), On the other hand, when the magnitude of a is negligible with respect to L (when a << L), it is approximated by Fraunhofer diffraction. When image degradation due to diffraction is expressed by the function F in the equation (2), a resolution limit appears when F is close to 2. λ is the wavelength of light.
F = a (2 / λL) 1/2 (2)

  In the case of F = 2 and λ = 0.4, a = 0.89 · L1 / 2 is obtained from the equation (2). This a is the resolution limit line width. When L is 150 μm, the resolution is 10.9 μm. Therefore, since the hole diameter of the columnar structure is preferably 80 nm to 20 μm, even if the columnar structure is formed simply using a photomask, image degradation due to Fraunhofer diffraction (a << L) is severe. In such a system, it is not considered that a columnar structure having an aspect ratio of 10 or more is formed in the film.

  That is, when the columnar structure is completely formed only by the first light irradiation step as in the prior art, the light passing through the photomask is diffracted from the projection area of the mask hole (that is, the area of the columnar structure) to the matrix. It will spread to reach the area. For this reason, even if the second light irradiation step is performed after the first light irradiation step as in the prior art, a significant refractive index difference does not occur between the matrix and the columnar structure.

  However, in this embodiment, the columnar structure 4 is not completely cured in the first light irradiation step, and only the formation position is determined. In the second light irradiation step, the entire matrix 2 and the columnar structure 4 are irradiated with parallel light in an incompletely cured state where there is a certain degree of hardness difference, and the entire structure is completely cured. At this time, due to the difference in cross-linking density with the matrix 2 due to the polymerization self-promoting effect of the columnar structure 4 and the composition distribution due to reaction diffusion between the columnar structure 4 and the matrix 2, a significant difference in refractive index between the two is obtained. Moreover, the columnar structure 4 having a high aspect ratio that extends substantially parallel to the film thickness direction of the molded body 1 can be formed. In addition, the difference in curing shrinkage between the columnar structure 4 and the matrix 2 is caused by the difference in crosslink density between the columnar structure 4 and the matrix 2 extending in the film thickness direction, and the molded body 1 is attracted to at least one surface of the columnar structure 4 and the matrix 2. Concavities and convexities 6 are formed in synchronization with the internal phase separation structure.

The manufactured molded body 1 was evaluated as follows.
(Diffraction efficiency calculation)
A laser beam having an intensity distribution of standard normal distribution is incident on the manufactured molded body 1 to measure the intensity of the 0th-order, 1st-order, and 2nd-order diffraction spots, and the measured intensity of the 1st-order diffraction spots is determined as the whole incident light. The value divided by the intensity was calculated as the diffraction efficiency of the molded body 1. When a plurality of diffraction spots appear, the total intensity is divided by the intensity of the entire incident light.
In the present embodiment, the molded body 1 has a diffraction efficiency of 10% or more (10% ≦ diffraction efficiency ≦ 100%).

  The molded body 1 can be used for an optical low-pass filter. In a photographing system such as a digital camera, moire (false color) is often a problem. This is because the sensors such as CCD and CMOS used are regularly arranged and interfere with the regular pattern included in the subject. One means for solving this problem is the introduction of an optical low-pass filter. The optical low-pass filter has an effect of suppressing moire by suppressing the influence of interference by separating input light into a plurality of points.

  In order to use the molded body 1 for a low-pass filter, first, an optically transparent optical element (for example, a transparent film) is laminated on the molded body 1 to form an optical laminated body, or The molded body 1 molded on a glass substrate (IR cut glass or the like) can be used as it is as a cover glass for the sensor. Since the optical laminate or the molded body 1 on the cover glass diffracts incident light to a specific position and intensity, by appropriately setting the diffraction angle and diffraction efficiency of the optical laminate, By appropriately setting the distance, it is possible to function as an optical low-pass filter. If the molded body 1 can be disposed in the optical system, an optically transparent optical element is necessarily laminated on the molded body 1 or the molded body 1 molded on the glass substrate is used as it is as a cover glass for the sensor. It does not have to be used.

  The present invention is not limited to the above-described embodiment, and various changes and modifications can be made within the scope of the technical idea described in the claims.

Hereinafter, the present invention will be specifically described by way of examples.
(Example 1)
In Example 1, 15 parts by mass of phenoxyethyl acrylate, 50 parts by mass of polyethylene glycol dimethacrylate (trade name: NK-ester 14G, manufactured by Shin-Nakamura Chemical Co., Ltd.), and NK-oligo U-2PPA (Shin Nakamura Chemical Co., Ltd.) (Manufactured) In a mixture consisting of 25 parts by mass and 10 parts by mass of trimethylolpropane trimethacrylate, 0.6 parts by mass of 1-hydroxycyclohexyl phenyl ketone was dissolved to obtain a photopolymerizable composition.

  The obtained photopolymerizable composition was coated on a 150 mm square and 1.1 mm thick glass substrate using a bar coater. A bar manufactured by Tester Sangyo Co., Ltd. was used. The bar coater was coated using a bar having a wound wire diameter of # 40. Next, a photomask in which 4 μm square light passage areas were arranged in a square lattice pattern at a pitch of 8 μm was disposed on the photopolymerizable composition. Ultraviolet parallel light having a substantially constant light intensity distribution was irradiated at 900 mJ / cm 2 from the upper direction of the photomask.

  Thereafter, the photomask was removed, and further irradiated with ultraviolet parallel light at 1200 mJ / cm 2 to polymerize and cure the photopolymerizable composition to obtain a plastic film.

FIG. 6 shows an optical microscope image of the obtained plastic film. From this observation image, it was confirmed that the columnar structures were regularly arranged in the manufactured plastic film. Moreover, a mode that the cross section of the film was observed with the optical microscope in FIG. 7 is shown. From the observation image of this cross section, it can be seen that the columnar structure in the manufactured plastic film penetrates completely from the light irradiation surface side of the film to the surface of the glass substrate side.
Furthermore, the surface of the plastic film was observed using a scanning interference microscope (New View) manufactured by ZYGO. As a result, the height of the surface irregularities on the light irradiation surface side was about 100 nm, and the height of the surface irregularities on the substrate side was about 50 nm. Further, the obtained plastic film has a thickness after curing of about 65 μm, an aspect ratio of about 16, a diffraction efficiency of about 67%, and has sufficient performance for use as an optical low-pass filter. An example in which a green laser is incident on this film and the pattern of the diffraction pattern is observed is shown in FIG.

  Next, the surface on the irradiation surface side of the obtained plastic film was coated with a photopolymerizable composition having the same composition as the plastic film and cured. First, the photopolymerizable composition was applied to the surface of a plastic film on a glass substrate by a spin coat method. An excessive amount of the photopolymerizable composition having the same composition as that used to prepare the obtained plastic film was supplied onto the plastic film, and then spin-coated at 1000 rpm for 1 minute. Next, the photopolymerizable composition was polymerized and cured by irradiating the applied photopolymerizable composition with 1500 mJ / cm 2 of ultraviolet light that was not parallel light in a nitrogen atmosphere.

  The thickness of the molded body obtained by coating and curing the surface on the irradiation surface side was about 75 μm. The diffraction efficiency of the plastic film after coating and curing was about 25%. Therefore, the diffraction efficiency of the molded body decreased by about 42% before and after coating and curing.

(Example 2)
In Example 2, only the pattern of the light transmitting portion of the photomask was changed from Example 1. Others used the photopolymerizable composition similar to Example 1, and obtained the plastic film with the same coating method and photocuring method. The photomask pattern used is a triangular lattice, the diameter of the light transmitting portion is 6 μm, and the pitch is 12 μm.
When the surface of the plastic film obtained in Example 2 was observed with a scanning interference microscope manufactured by ZYGO in the same manner as in Example 1, the height of the surface irregularities on the light irradiation surface side was about 360 nm, and the surface on the substrate side was The height of the unevenness was about 70 nm. Moreover, the diffraction efficiency of the plastic film obtained in Example 2 was about 75%.

(Example 3)
In Example 3, the pattern of the light transmitting portion of the photomask and the diameter of the wire of the bar coater were changed from Example 1. Others used the photopolymerizable composition similar to Example 1, and obtained the plastic film with the same photocuring method. The photomask pattern used is a triangular lattice, the width of the light transmission part is 4 μm, and the pitch is 8 μm. In addition, the bar coater was coated using a bar having a diameter of 55 rolled.
When the surface of the plastic film obtained in Example 3 was observed with a scanning interference microscope manufactured by ZYGO in the same manner as in Example 1, the surface unevenness on the light irradiation surface side was about 150 nm, and the surface on the substrate side was The height of the unevenness was about 60 nm.
The plastic film obtained in Example 3 had a diffraction efficiency of about 50%.

(Comparative Example 1)
Unlike Example 1, Comparative Example 1 is an example in which the surface on the irradiation surface side of the photopolymerizable composition was wet-laminated with an optical film and then irradiated with light, followed by polymerization and curing.

In Comparative Example 1, as shown in FIG. 9, the photopolymerizable composition 20 having the same composition as that of Example 1 is a transparent film made of PET (polyethylene terephthalate) on the irradiation surface side, and has a 100 mm square and a thickness. It inject | poured into the film form in the glass cell 22 which is 50 micrometers.
Next, a photomask 24 in which square light passing areas of 4 μm square were arranged in a square lattice pattern at a pitch of 8 μm was disposed on the photopolymerizable composition. Ultraviolet parallel light having a substantially constant light intensity distribution was irradiated at 900 mJ / cm ² from above the photomask.
Thereafter, the photomask 24 was removed, and further irradiated with ultraviolet parallel light at 1200 mJ / cm ² to polymerize and cure the photopolymerizable composition to obtain a plastic film.

  In addition, as in the examples, the diffraction pattern was evaluated by irradiating a laser beam perpendicularly to the surface of the obtained plastic film, and diffraction points due to the regular phase separation structure inside the polymer were observed. It was done. The diffraction efficiency was 25%, and the film thickness was 40 to 70 μm. Further, when the surface of the plastic film was observed with a scanning interference microscope manufactured by ZYGO as in the example, surface unevenness synchronized with the columnar structure inside the film was hardly confirmed on the light irradiation surface side. The height of the surface irregularities on the substrate side was about 30 nm.

Subsequently, also in the comparative example, the surface on the irradiation surface side of the obtained plastic film was coated in the same manner as in the example.
The thickness of the molded body obtained by coating and curing the surface on the irradiation surface side was 50 to 80 μm. The diffraction efficiency of the plastic film after coating and curing was 23%, and the efficiency was almost unchanged before and after coating.

As described above, it was found that the comparative example had lower diffraction efficiency than the example, although the film thickness was the same. It was also found that the height of the surface irregularities was lower than that of the example. Since the surface of the plastic film of the comparative example was coated with the photopolymerizable composition having the same composition as the example by the spin coat method in the same manner as in the example, the diffraction efficiency was hardly lowered before and after being cured. It was found that the surface irregularities of the plastic film prepared by wet laminating the film hardly contributed to the diffraction efficiency.
As described above, it was found that when a concavo-convex structure having a height of 10 nm or more and less than 1 μm synchronized with the phase separation structure inside the molded body was formed, a molded body having high diffraction efficiency (high performance) could be produced.

It is a perspective view of a part of the molded body schematically showing the configuration of the molded body of a preferred embodiment of the present invention. It is a top view which shows the manufacturing process of the molded object of preferable embodiment of this invention. It is sectional drawing which shows the manufacturing process of the molded object of preferable embodiment of this invention. It is a typical top view which shows the structure of the photomask used with the manufacturing method of the molded object of preferable embodiment of this invention. It is a typical top view which shows the structure of the photomask used with the manufacturing method of the molded object of other preferable embodiment of this invention. It is a figure which shows the optical microscope image of the molded object of an Example. It is a figure which shows the optical microscope image of the cross section of the molded object of an Example. It is a diffraction image by the molded object (plastic film) of an Example. It is typical sectional drawing for demonstrating the manufacturing method of the molded object of a comparative example.

Explanation of symbols

1: Molded body 2: Matrix 4: Columnar structure 6: Concavity and convexity

Claims (10)

A phase separation comprising: a matrix made of a photopolymerizable composition; and a plurality of columnar structures that are arranged in the matrix and have a circular or polygonal cross section made of a photopolymerizable composition that has a refractive index different from that of the matrix. A molded body having a structure,
At least one side surface has irregularities with a height of 10 nm or more and less than 1 μm synchronized with the phase separation structure;
A molded product characterized by that. Each of the plurality of columnar structures is oriented in substantially the same direction and is arranged in a regular lattice shape in a plane perpendicular to the orientation direction.
The molded product according to claim 1. The plurality of columnar structures have substantially the same cross-sectional shape perpendicular to the alignment direction.
The molded product according to claim 1 or 2. The columnar structure has an aspect ratio of 10 or more.
The molded body according to any one of claims 1 to 3. The photopolymerizable composition is an acrylic photopolymerizable composition,
The molded body according to any one of claims 1 to 4.   An optical low-pass filter comprising the molded body according to claim 1. A phase separation structure comprising a matrix made of a photopolymerizable composition, and a plurality of columnar structures made of a photopolymerizable composition and having a refractive index different from that of the matrix disposed in the matrix, and at least one side A method for producing a molded article having irregularities synchronized with the phase separation structure on the surface,
Applying a photopolymerizable composition containing a photocurable monomer or oligomer and a photopolymerization initiator on a substrate;
A step of arranging a photomask having a light passage region and a light non-passage region between the light source and the base material on which the photocurable resin is disposed;
The photopolymerizable composition is irradiated from the light source with parallel light having a full width at half maximum of 100 nm or less and a substantially constant light intensity distribution toward the photopolymerizable composition on the substrate through the photomask. A first light irradiation step of curing a portion irradiated with parallel light to an incompletely cured state,
The photomask is removed, and the photopolymerizable composition on the substrate is irradiated with parallel light having a full width at half maximum of 100 nm or less and a substantially constant light intensity distribution toward the photopolymerizable composition. A second light irradiation step for completing the curing,
The manufacturing method of the molded object characterized by the above-mentioned. In the first light irradiation step and the second light irradiation step, the photopolymerizable composition applied on the substrate is irradiated with parallel light in an inert gas atmosphere.
The molded object manufacturing method of Claim 7. In the first light irradiation step, the part irradiated with parallel light in the photopolymerizable composition is cured to a curing degree of 10% or more and 80% or less.
The manufacturing method of the molded object of Claim 7 or 8. In the photomask, a large number of the light passing areas are arranged in a regular lattice shape in the light non-passing area.
The manufacturing method of the molded object of any one of Claims 7 thru | or 9.