JP2009175401A - Periodic grating structure having visible angle control function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for periodic grating structure having a visible angle control function, and a technique capable of browsing information only from an observer existing along a specified direction, by controlling an angle of visibility in a screen, by using it on a surface of a display, a display window, a show window, a glass pane, a road/traffic sign, a sign board and the like. <P>SOLUTION: A mono-particle-film etching mask is arranged on at least one face of a substrate, and the periodic grating structure X satisfying the condition described in following is provided using the mask by a dry etching method, so as to prepare the periodic grating structure having the visible angle control function. The condition is: the most frequent pitch C of irregularity is 225-415 nm in the periodic grating structure X, while the most frequent high D is 10-250 nm, and a ratio of the most frequent high D to the most frequent pitch C is 1.0 or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for manufacturing a periodic grating structure having a viewing angle control function.
More specifically, information is seen only from an observer in a specific direction by controlling the viewing angle of the screen by using it on the surface of a display, display window, show window, window glass, road / traffic sign, signboard, etc. It can be related to technology.

  Conventionally, bank terminals such as PCs, mobile phones, cash dispensers (Cash Dispenser), and automatic teller machines (ATMs) have been operated from the viewpoint of privacy and personal information protection. There is a need for a function that allows the screen to be seen only by the person himself / herself and not to be seen by other people who are next to or behind the screen. In addition, it is desirable to monitor the seats in the aircraft so that the content can be enjoyed without inconvenience the surroundings by devising the image so that the image cannot be seen in the adjacent seat. The technology that limits the viewing angle has already been put to practical use in the screens of personal computers, mobile phones, and seats in airplanes, and it is expected that the use will be expanded in the future for other security related purposes.

  Patent Document 1 describes a film (louver film) having low refractive index layers and high refractive index layers alternately. With this configuration, incident light with a certain angle or more with respect to the film plane cannot be transmitted through the alternately arranged low refractive index layer and high refractive index layer, and as a result, the display cannot be visually recognized. It is described that the viewing angle is controlled by the thicknesses of the low refractive index layer and the high refractive index layer.

Patent Document 2 discloses a viewing angle changing means comprising a liquid crystal between two glass substrates, two polarizing plates laminated on the outside of the glass substrate, and two electrode layers applied on the inside of the two glass substrates. Is described. It is described that a narrow viewing angle is obtained by applying a voltage between electrodes.

Patent Document 3 has an absorption axis made of a polarizer that absorbs light having a vibration surface in a specific direction so as to be superimposed on a liquid crystal display element that emits display light, and the angle of the absorption axis can be freely set by applying a voltage. A display device that can be changed is described.

In Patent Document 4, by combining a plurality of prism layers on the surface, when viewed from outside from a predetermined angle, light rays from that position are totally reflected by the prism surface in the structure, so that the displayed information can be visually confirmed. The technology of the peep prevention medium which disappears is described.

Patent Document 5 describes a technology in which a porous plate having a plurality of through holes is formed between a display unit such as a liquid crystal display panel and a light source unit so that an image cannot be seen due to total reflection from outside a certain viewing angle. ing.
U.S. Pat. No. 4,128,685 Japanese Patent Laid-Open No. 2004-62094 JP-A-8-114795 JP 2005-288836 A JP-A-2005-234096

However, the technique for limiting the viewing angle includes the following problems. That is, Patent Documents 2 and 3 require a device that applies a voltage with a complicated structure and cannot be manufactured at a low cost and in a large area. Moreover, although patent document 1, patent document 4, and patent document 5 are based on the interface reflection which arises from the difference in refractive index, when construction which provides interface reflection to the whole display range will perform the problem that visibility falls. In addition, there is a problem that the cost increases because the number of interfaces must be increased in order to improve the viewing angle limiting performance with such a structure.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the fine structure which has the periodic grating structure X which radiates | emits a diffracted light to the angle which intends with high precision.

The present invention employs the following configuration.
[1] A viewing angle control function characterized by disposing a single particle film etching mask on at least one surface of a substrate and providing a periodic grating structure X satisfying the following conditions by dry etching using the mask. A two-dimensional periodic lattice structure.
Periodic grating structure X: the mode pitch C of irregularities is 225 to 415 nm, the mode height d is 10 to 250 nm, and the ratio of the mode height d to the mode pitch C is 1.0 or less 2 Dimensional periodic lattice structure.
[2] A method of arranging the single particle film etching mask includes a dropping step of dropping a dispersion in which particles are dispersed in a volatile solvent having a specific gravity smaller than that of water onto a liquid surface of water in a water tank; A single particle film forming step of forming a single particle film composed of the particles on the liquid surface of water by volatilizing, a transition step of transferring the single particle film to the substrate surface, and a substrate coated with the single particle film The two-dimensional periodic grating structure having a viewing angle control function according to claim 1, comprising a fine processing step of creating a periodic grating structure X by performing fine processing by a dry etching method using the single particle film as a mask.
3. The two-dimensional periodic grating according to claim 1 or 2, wherein the two-dimensional periodic grating structure X has a viewing angle limiting function of ± 5 to ± 90 ° and has little scattered light. Structure.
[4] The periodic grating structure X created by the method according to at least one of claims 1 to 3 is used as a master and is replicated using a shape transfer technique. The two-dimensional periodic lattice structure described.
[5] The metal thin film layer is formed on at least one method selected from a vacuum evaporation method, a sputtering method, and an electroless plating method on the structural surface of the periodic grating structure X produced by at least one method of claims 1 to 4. A two-dimensional periodic grating structure having a viewing angle control function.

  According to the present invention, it is possible to manufacture a fine structure having a viewing angle control function provided with a highly accurate periodic grating structure X that emits diffracted light at a target angle. Furthermore, it is possible to provide a shape transfer body using the obtained fine structure as an original plate, and a composite obtained by adding a metal thin film layer to the original plate or the shape transfer body. All of these have an advanced viewing angle limiting function.

[Periodic grating structure X]
The periodic grating structure X of the present invention is a fine structure that satisfies the following condition, in which a single particle film etching mask is disposed on at least one surface of a substrate and is formed by dry etching using the mask.
Periodic grating structure X: the concave / convex mode pitch C is 225 to 415 nm, the mode height d is 10 to 250 nm, and the ratio of the mode height d to the mode pitch C is 1.0 or less 2 Dimensional periodic lattice structure.

The mode pitch C of the periodic grating structure X is specifically a value measured by the following method.
First, on the surface where the periodic grating structure X exists (the surface where the periodic grating structure X exists), a square region parallel to the substrate surface whose one side is 30 to 40 times the most frequent pitch C is randomly extracted. Obtain an atomic force microscope image. For example, when the most frequent pitch C is about 300 nm, an image of an area of 9 μm × 9 μm to 12 μm × 12 μm is obtained. Then, this image is waveform-separated by two-dimensional Fourier transform to obtain an FFT image (fast Fourier transform image). Next, the distance from the zero-order peak to the primary peak in the profile of the FFT image is obtained. The reciprocal of the distance thus obtained is the most frequent pitch C ₁ in this region. At this time, the variation in pitch between particles in each image can be evaluated from the area of the primary peak in the profile of the FFT image. Such a process is similarly performed for a total of 25 or more regions of the same area selected at random, and the most frequent pitches C _{1 to} C ₂₅ in each region are obtained. The average value of the most frequent pitches C _{1 to} C _{25 in} the ₂₅ or more regions thus obtained is the most frequent pitch C. At this time, the regions are preferably selected at least 1 mm apart, more preferably 5 mm to 10 mm apart.

  The most frequent pitch C used in the present invention is 225 to 415 nm, more preferably 300 to 415 nm. The reason why the mode pitch range of the periodic grating structure X is set to 225 to 415 nm is to provide a viewing angle limiting effect when a white light source is used. That is, a surface with a mode pitch of 225 nm is a condition where diffracted light comes out at a diffraction angle of about 90 ° when blue-violet light having a wavelength of 450 nm is incident at an incident angle of 90 °. When blue-violet light having a wavelength of 450 nm is incident at an incident angle of 90 °, the diffracted light comes out at a diffraction angle of about 5 °. Therefore, if the most frequent pitch is in the range of 225 to 415 nm, the diffracted light appears in the range of 5 ° to 90 °, so that visibility is good for an observer standing in front of the display or display window of the present invention. On the other hand, it is difficult for the bystander located beside or obliquely behind the observer to grasp the contents of the display and the display window because the diffracted light interferes. Moreover, when the range of the most frequent pitch is 300 to 415 nm, the diffraction angle can be set to about 5 ° or more to 30 ° or more. It is preferable because it has a particularly high effect of preventing peeping of people in the area.

Furthermore, in the present invention, 450 to 750 nm is selected as the wavelength range that hinders visibility. Actually, the visible light wavelength range is wider than this, but the wavelength that the human eye feels brightest is about 550 to 600 nm, and the wavelengths below 450 nm and larger than 750 nm feel dark and dark red and dark red, respectively. This is because the wavelength of the diffracted light used for limiting the viewing angle, which is the object of the invention, is not suitable. The diffracted light referred to in the present invention is all first-order diffracted light. The periodic grating structure X also generates second-order diffracted light, third-order diffracted light,... N-th order diffracted light, and when these are also superimposed on the first-order diffracted light, an accurate intensity distribution of diffracted light can be obtained. Since the intensity after the next diffracted light is low, the effect of limiting the viewing angle, which is an object of the present invention, is slight. Therefore, in the present invention, the material design is made ignoring the influence of the diffracted light after the second order diffracted light.

The periodic grating structure X is a two-dimensional structure in which irregularities are repeated in a two-dimensional direction. Examples of the periodic grating structure X include a protrusion structure having a sine wave or pseudo sine wave in cross section, a quadrangular prism, a triangular prism, a cylinder, or a repeating convex or concave portion such as a quadrangular pyramid, a triangular pyramid, or a cone. From the viewpoint of the difficulty of making it, it is preferable that the protrusion has a sine wave or pseudo sine wave in cross section.
The two-dimensional structure may be a grid, houndstooth, hexagon (6-way close-packed), or other layout, but may be a hexagon (6-way close-packed). It is preferable from the characteristics of the mask making method of the present invention. As will be described later, the single particle film etching mask can create a two-dimensional structure in which hexagons are arranged, and it is possible to create a periodic lattice structure X with high regularity by dry etching using this.

  Here, the average particle diameter A of the particles is the average primary particle diameter of the particles constituting the single particle film, and is obtained by fitting the particle size distribution obtained by the particle dynamic light scattering method to a Gaussian curve. It can obtain | require by a conventional method from the peak obtained.

  Next, the mode height d and the aspect ratio will be described. In order to function satisfactorily as a viewing angle limiting optical member, it is also necessary to devise a technique that generates as little scattered light as possible, in addition to the fact that the periodic grating structure effectively emits diffracted light. This is because when scattered light is generated, the visibility of a person near the front is significantly reduced. Therefore, in the present invention, the mode height d of the microstructure is 10 to 250 nm, more preferably 20 to 100 nm, and the aspect ratio (height / diameter of the circular bottom) is 1.0 or less, preferably 0.5 or less. The smaller the mode height d and the aspect ratio, the better the generation of scattered light in the periodic grating structure. The most frequent height d is about 10 to 250 nm and sufficiently gives diffracted light. However, when the mode height is about 20 to 100 nm, the surface structure has less scattered light. With such a height and aspect ratio, sufficient diffracted light can be obtained at the part where the fine protrusions are formed, and the occurrence of scattered light is also suppressed. While the inside of the display window such as a display window or the like can be satisfactorily viewed, the diffracted light can interfere with the viewing from other positions and the visibility can be effectively reduced.

Specifically, the mode height d of the periodic grating structure X is obtained as follows. First, on the surface where the periodic grating structure X exists (the surface where the periodic grating structure X exists), a square region parallel to the substrate surface whose one side is 30 to 40 times the most frequent pitch C is randomly extracted. Obtain an atomic force microscope image. For example, when the most frequent pitch C is about 300 nm, an image of an area of 9 μm × 9 μm to 12 μm × 12 μm is obtained. Next, a profile is created for the irregularities of the fine protrusions appearing in the image measured by the atomic force microscope. Profile creation is usually possible with the image processing software attached to the atomic force microscope, so it is preferable to use it. The uneven profile is obtained by creating a cross section passing through the center of a certain protrusion and the center of the protrusion adjacent thereto. The difference between the highest portion and the lowest portion of the irregularities and the height d _1. The same operation is similarly performed on a total of 25 or more regions of the same area selected at random, and the most frequent heights d ₁ to d ₂₅ in each region are obtained. The average value of the modal height d ₁ to d ₂₅ is the most frequent height d at 25 locations or more areas thus obtained. At this time, the regions are preferably selected at least 1 mm apart, more preferably 5 mm to 10 mm apart.

  Since the periodic grating structure X of the present invention has the periodic grating structure X on the surface, it itself is suitably used as a high-performance viewing angle control sheet. Master) and the like. By transferring the original plate to obtain a mold for nanoimprint or injection molding, and using this mold, a high-performance viewing angle control sheet can be stably mass-produced at low cost.

The thickness of the material having the periodic grating structure X on the surface is not particularly limited, but when used as a film to be stuck on the surface of a display such as a personal computer, a show window, an exhibition frame, various lenses, various display windows, etc. The thickness is preferably 10 to 500 μm. On the other hand, when it is used as it is for a transparent material constituting the surface of a display such as a personal computer, a show window, an exhibition frame, various lenses, various display windows, etc., the thickness can be appropriately set appropriately.
Moreover, when using as an original of a structure transfer technique, it is preferable to set it as the thickness of 100-5000 micrometers.

[Manufacturing method of periodic grating structure X]
The manufacturing method of the periodic grating structure X of the present invention is characterized in that a single particle film etching mask is disposed on at least one surface of a substrate, and the periodic grating structure X is provided by dry etching using the mask. To do.

[substrate]
The substrate is available from commercially available products, but is appropriately selected according to the use and dry etching conditions. For example, as materials, semiconductors such as silicon and gallium arsenide, metals such as aluminum, iron and copper, various glasses, quartz glass, mica, metal oxides such as sapphire (Al ₂ O ₃ ), polyethylene terephthalate (PET), polyethylene Examples thereof include polymer materials such as naphthalate and triacetylcellulose. Further, the surface of the substrate may be coated with another material or chemically altered. For example, when the microstructure obtained by the subsequent etching process is used as it is as the viewing angle limiting optical member, a transparent material such as glass, quartz glass, or a polymer material with transparency is preferable as the substrate material. When used as a master plate for nanoimprint mold for producing a viewing angle limiting optical part agent, it is widely used as an etching object such as quartz glass and silicon as a substrate material, and has high smoothness. Those are preferred. Use of a material having low smoothness is not preferable because scattered light is generated from unevenness on the surface.

The thickness of the substrate is not particularly limited, but the fine structure obtained by the subsequent etching process is stuck on the surface of a display such as a personal computer, a show window, an exhibition frame, various lenses, or various display windows. When trying to improve visibility, that is, when a fine structure is formed on an optical film, it is preferable to use a substrate film having a thickness of 10 to 500 μm. On the other hand, the obtained fine structure may be used as it is for a transparent material constituting the surface of a display such as a personal computer, a display window, an exhibition frame, various lenses, various display windows, etc. Thickness can be set.
Moreover, when using the obtained periodic-grating structure X microstructure as a master plate of nanoimprint or injection molding, it is preferable to use a substrate having a thickness of 100 to 5000 μm.

[Single particle film etching mask]
As shown in FIG. 1, the single particle film etching mask of the present invention is an etching mask composed of a single particle film in which a large number of particles are two-dimensionally closely packed, and is formed of particles defined by the following formula (1). Arrangement deviation D (%) is 10% or less.
D [%] = | B−A | × 100 / A (1)
In the formula (1), A is the average particle diameter of the particles M constituting the single particle film, and B is the average pitch between the particles in the single particle film. | B−A | indicates the absolute value of the difference between A and B.

  Here, the average particle diameter A of the particles M is the average primary particle diameter of the particles constituting the single particle film, and the particle size distribution obtained by the particle dynamic light scattering method is fitted to a Gaussian curve. It can obtain | require by a conventional method from the obtained peak.

On the other hand, the pitch between particles is the distance between the vertices of two adjacent particles in the sheet surface direction, and the most frequent pitch B is the average of these. If the particles are spherical, the distance between the vertices of adjacent particles is equal to the distance between the centers of the adjacent particles.
Specifically, the most frequent pitch B between particles in the single particle film etching mask is obtained as follows.
First, an atomic force microscope image is obtained for a square region parallel to the sheet surface 30 to 40 times the most frequent pitch B between particles in a randomly selected region in the single particle film etching mask. For example, in the case of a single particle film using particles having a particle size of 300 nm, an image of a region of 9 μm × 9 μm to 12 μm × 12 μm is obtained. Then, this image is waveform-separated by Fourier transform to obtain an FFT image (fast Fourier transform image). Next, the distance from the zero-order peak to the primary peak in the profile of the FFT image is obtained. The reciprocal of the distance thus obtained is the most frequent pitch B ₁ in this region. Such processing is similarly performed on a total of 25 or more regions having the same area selected at random, and the most frequent pitches B _{1 to} B ₂₅ in each region are obtained. The average value of the mode pitches B _{1 to} B _{25 in} the ₂₅ or more regions obtained in this way is the mode pitch B in the equation (1). In this case, the regions are preferably selected at least 1 mm apart, more preferably 5 mm to 10 mm apart. At this time, the variation in pitch between particles in each image can be evaluated from the area of the primary peak in the profile of the FFT image.

  A single-particle film etching mask having a particle arrangement deviation D of 10% or less can be used satisfactorily as a periodic lattice structure because each particle is two-dimensionally closely packed and the interval between the particles is controlled. Therefore, by using such a single particle film as an etching mask and forming fine protrusions at positions corresponding to the respective particles on the substrate, a highly accurate periodic lattice pattern can be obtained. Since such two-dimensional close-packing is based on the principle of self-organization described later, it includes some lattice defects. However, such a lattice defect in the two-dimensional close-packing is advantageous for the purpose of emitting uniform diffused light as an optical member for viewing angle limiting applications because it creates a variety of filling orientations.

When a fine grating pattern is formed on a substrate to manufacture a periodic grating structure having a viewing angle limiting function of ± 5 to ± 90 ° and an original for transferring the structure, a single particle film etching mask is formed. As the particles, those having an average particle diameter A determined by a dynamic light scattering method of 225 to 415 nm are used. Since the average particle diameter A of the particles and the pitch of the formed fine structure are substantially the same value, the pitch of the periodic grating fine structure formed on the substrate surface as a result of dry etching is also 225 to 415 nm, which is ± 5 to ± 90 °. An optical member or an optical element that emits diffracted light in the range can be created, and a periodic grating pattern suitable for a viewing angle limiting application can be formed. Since the mode pitch B of the single-particle film etching mask is a value approximately approximate to the mode pitch C of the periodic grating structure, it is preferably 225 to 415 nm, and preferably 300 to 415 nm for the reason described above. Further preferred.
Further, the coefficient of variation (the value obtained by dividing the standard deviation by the average value) of the particle diameter A is preferably 20% or less, more preferably 10% or less, and further preferably 5% or less. preferable. If particles having a small variation coefficient of particle size, that is, particles having a small particle size variation are used in this way, in the manufacturing process of a single particle film etching mask, which will be described later, it becomes difficult to generate a defect portion where particles are not present, and an alignment shift D It is easy to obtain a single particle film etching mask having a thickness of 10% or less.

Particle materials include metals such as Al, Au, Ti, Pt, Ag, Cu, Cr, Fe, Ni, and Si, and metal oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ , MgO ₂ , and CaO ₂ . In addition to organic polymers such as polystyrene and polymethyl methacrylate, one or more of semiconductor materials and inorganic polymers can be employed.

[Method for arranging single-particle film etching mask]
Such a single particle film etching mask is arranged on at least one surface of a substrate which is an object to be etched, and is arranged on the substrate by a method using a so-called LB method (Langmuir-Blodget method). it can.
Specifically, a dropping step of dropping a dispersion in which particles are dispersed in a solvent onto the liquid surface in the water tank, a single particle film forming step of forming a single particle film made of particles by volatilizing the solvent, It can be arranged on the surface of the substrate by a method having a transfer step of transferring the particle film onto the substrate.
This method combines the accuracy of monolayering, ease of operation, compatibility with large areas, reproducibility, etc., and is superior to, for example, the liquid thin film method and particle adsorption method, and can be applied to industrial production levels. .
A preferred method for producing a single particle film etching mask will be specifically described below with an example.

[Drip process and single particle film formation process]
First, a dispersion liquid is prepared by adding particles having a hydrophobic surface to a hydrophobic organic solvent composed of one or more of volatile solvents such as chloroform, methanol, ethanol, and methyl ethyl ketone. On the other hand, a water tank (trough) is prepared, and water is added thereto as a liquid for developing particles on the liquid surface (hereinafter sometimes referred to as lower layer water).
And a dispersion liquid is dripped at the liquid level of lower layer water (drip process). Then, the solvent as the dispersion medium is volatilized, and the particles are developed in a single layer on the liquid surface of the lower layer water, so that a two-dimensional close-packed single particle film can be formed (single particle film forming step). ).
Thus, when a hydrophobic particle is selected as the particle, it is necessary to select a hydrophobic particle as the solvent. On the other hand, in that case, the lower layer water needs to be hydrophilic, and water is usually used as described above. By combining in this way, as will be described later, self-organization of particles proceeds and a two-dimensional close packed single particle film is formed. However, hydrophilic particles and solvents may be selected. In that case, a hydrophobic liquid is selected as the lower layer water.

  The particle concentration of the dispersion dropped into the lower layer water is preferably 1 to 10% by mass. Further, the dropping rate is preferably 0.001 to 0.01 ml / second. If the concentration of the particles in the dispersion and the amount of dripping are in such a range, the particles are partially agglomerated in a cluster to form two or more layers, defective portions where no particles are present, and the pitch between particles is A tendency of spreading and the like is suppressed, and a single particle film in which each particle is two-dimensionally closely packed with high accuracy is more easily obtained.

  As the particles having hydrophobic surfaces, among the previously exemplified particles, particles made of organic polymers such as polystyrene and having a hydrophobic surface may be used. It may be used after making it hydrophobic with an agent. As the hydrophobizing agent, for example, a surfactant, a metal alkoxysilane, or the like can be used.

The method of using a surfactant as a hydrophobizing agent is effective for hydrophobizing a wide range of materials, and is suitable when the particles are made of metal, metal oxide, or the like.
As the surfactant, cationic surfactants such as brominated hexadecyltrimethylammonium and brominated decyltrimethylammonium, and anionic surfactants such as sodium dodecyl sulfate and sodium 4-octylbenzenesulfonate can be suitably used. Moreover, alkanethiol, a disulfide compound, tetradecanoic acid, octadecanoic acid, etc. can also be used.

Such a hydrophobizing treatment using a surfactant may be performed in a liquid by dispersing particles in a liquid such as an organic solvent or water, or may be performed on particles in a dry state.
When performed in a liquid, for example, in a volatile organic solvent composed of one or more of chloroform, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl ethyl ketone, toluene, hexane, cyclohexane, ethyl acetate, butyl acetate and the like. Then, the particles to be hydrophobized may be added and dispersed, and then the surfactant may be mixed and further dispersed. If the particles are dispersed in advance in this way and then a surfactant is added, the surface can be more uniformly hydrophobized. Such a hydrophobized dispersion can be used as it is as a dispersion for dripping onto the surface of the lower layer water in the dropping step.

If the particles to be hydrophobized are in the form of an aqueous dispersion, a surfactant is added to the aqueous dispersion, the surface of the particles is hydrophobized with an aqueous phase, and then an organic solvent is added to make the hydrophobized treatment. An oil phase extraction method is also effective. The dispersion thus obtained (a dispersion in which particles are dispersed in an organic solvent) can be used as it is as a dispersion for dropping onto the liquid surface of the lower layer water in the dropping step. In order to improve the particle dispersibility of this dispersion, it is preferable to appropriately select and combine the type of organic solvent and the type of surfactant. By using a dispersion having a high particle dispersibility, the particles can be prevented from agglomerating in clusters, and a single particle film in which each particle is two-dimensionally closely packed with high accuracy can be obtained more easily. For example, when chloroform is selected as the organic solvent, it is preferable to use brominated decyltrimethylammonium as the surfactant. In addition, a combination of ethanol and sodium dodecyl sulfate, a combination of methanol and sodium 4-octylbenzenesulfonate, a combination of methyl ethyl ketone and octadecanoic acid, and the like can be preferably exemplified.
The ratio of the particles to be hydrophobized and the surfactant is preferably such that the mass of the surfactant is 1/3 to 1/15 times the mass of the particles to be hydrophobized.
In addition, in such a hydrophobizing treatment, it is effective in terms of improving particle dispersibility to stir the dispersion during the treatment or to irradiate the dispersion with ultrasonic waves.

The method of using metal alkoxysilane as a hydrophobizing agent is effective when hydrophobizing particles such as Si, Fe, and Al, and oxide particles such as AlO ₂ , SiO ₂ , and TiO _2. The present invention is not limited and can be applied basically to particles having a hydroxyl group on the surface.
As the metal alkoxysilane, monomethyltrimethoxysilane, monomethyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, C-styryltrimethoxy Silane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3methacryloxy Propyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (amino Ethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyl Examples include trimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

  When using a metal alkoxysilane as a hydrophobizing agent, the alkoxysilyl group in the metal alkoxysilane is hydrolyzed to a silanol group, and the silanol group is dehydrated and condensed to a hydroxyl group on the particle surface to effect hydrophobicity. Therefore, the hydrophobization using metal alkoxysilane is preferably performed in water. Thus, when hydrophobizing in water, it is preferable to stabilize the dispersion state of the particles before hydrophobization by using a dispersant such as a surfactant, for example. Since the hydrophobizing effect of the alkoxysilane may be reduced, the combination of the dispersant and the metal alkoxysilane is appropriately selected.

  As a specific method for hydrophobizing with a metal alkoxysilane, first, particles are dispersed in water, and this is mixed with a metal alkoxysilane-containing aqueous solution (an aqueous solution containing a hydrolyzate of metal alkoxysilane), and from room temperature. The reaction is carried out for a predetermined time, preferably 6 to 12 hours, with appropriate stirring in the range of 40 ° C. By carrying out the reaction under such conditions, the reaction proceeds moderately and a dispersion of sufficiently hydrophobized particles can be obtained. When the reaction proceeds excessively, the silanol groups react with each other to bond the particles, the particle dispersibility of the dispersion decreases, and the resulting single particle film has particles partially agglomerated in clusters 2 It tends to be more than a layer. On the other hand, when the reaction is insufficient, the surface of the particles is not sufficiently hydrophobized, and the resulting single particle film tends to have a wide pitch between the particles.

Moreover, since metal alkoxysilanes other than amines are hydrolyzed under acidic or alkaline conditions, it is necessary to adjust the pH of the dispersion to acidic or alkaline during the reaction. Although there is no restriction | limiting in the adjustment method of PH, According to the method of adding the acetic acid aqueous solution of 0.1-2.0 mass% density | concentration, since the effect of silanol group stabilization is acquired other than acceleration | stimulation, it is preferable. .
The ratio of the particles to be hydrophobized and the metal alkoxysilane is preferably in the range where the mass of the metal alkoxysilane is 1/10 to 1/100 times the mass of the particles to be hydrophobized.

  After the reaction for a predetermined time, one or more of the above-mentioned volatile organic solvents are added to the dispersion, and the particles hydrophobized in water are subjected to oil phase extraction. At this time, the volume of the organic solvent to be added is preferably in the range of 0.3 to 8 times the dispersion before the addition of the organic solvent. The dispersion thus obtained (a dispersion in which particles are dispersed in an organic solvent) can be used as it is as a dispersion for dropping onto the liquid surface of the lower layer water in the dropping step. In such a hydrophobizing treatment, it is preferable to carry out stirring, ultrasonic irradiation, etc. in order to improve the particle dispersibility of the dispersion during the treatment. By increasing the particle dispersibility of the dispersion, it is possible to suppress the aggregation of particles in a cluster shape, and it becomes easier to obtain a single particle film in which each particle is two-dimensionally closely packed with high accuracy.

  In order to further improve the accuracy of the formed single particle film, the dispersion before dropping onto the liquid surface is microfiltered with a membrane filter or the like, and aggregated particles (from a plurality of primary particles) present in the dispersion are used. Secondary particles) are preferably removed. If the microfiltration is performed in advance as described above, it is difficult to generate a portion where two or more layers are formed or a defective portion where particles are not present, and it is easy to obtain a single particle film with high accuracy. Assuming that a defect portion having a size of several to several tens of μm exists in the formed single particle film, a surface pressure sensor that measures the surface pressure of the single particle film in a transition step described later in detail, Even if an LB trough device having a movable barrier that compresses the single particle film in the liquid surface direction is used, such a defective portion is not detected as a difference in surface pressure, and a highly accurate single particle film etching mask is obtained. Things get harder.

  Furthermore, such a single particle film forming step is preferably performed under ultrasonic irradiation conditions. When the single particle film formation process is performed while irradiating ultrasonic waves from the lower layer water to the water surface, the close packing of particles is promoted, and a single particle film in which each particle is two-dimensionally close packed with high accuracy is obtained. It is done. At this time, the ultrasonic output is preferably 1 to 1200 W, and more preferably 50 to 600 W. Moreover, although there is no restriction | limiting in particular in the frequency of an ultrasonic wave, For example, 28 kHz-5 MHz are preferable, More preferably, they are 700 kHz-2 MHz. In general, when the vibration frequency is too high, energy absorption of water molecules starts and a phenomenon in which water vapor or water droplets rise from the surface of the water occurs, which is not preferable for the LB method of the present invention. In general, when the frequency is too low, the cavitation radius in the lower layer water is increased, bubbles are generated in the water, and rise toward the water surface. When such bubbles accumulate under the single particle film, the flatness of the water surface is lost, which is inconvenient for the implementation of the present invention. In addition, standing waves are generated on the water surface by ultrasonic irradiation. If the output is too high at any frequency, or if the wave height of the water surface becomes too high due to the tuning conditions of the ultrasonic transducer and transmitter, the single particle film will be destroyed by the water surface wave, so care must be taken.

If the frequency of the ultrasonic wave is appropriately set in consideration of the above, close-packing of particles can be effectively promoted without destroying the single particle film being formed. In order to perform effective ultrasonic irradiation, the natural frequency calculated from the particle size of the particles should be used as a guide. However, when the particle diameter is small, for example, 100 nm or less, the natural frequency becomes very high, and it is difficult to apply ultrasonic vibration as calculated. In such a case, the calculation is performed assuming that the natural vibration corresponding to the mass of the particle dimer, trimer,... Can be reduced. Even when ultrasonic vibration corresponding to the natural frequency of the aggregate of particles is applied, the effect of improving the particle filling rate is exhibited. The ultrasonic irradiation time may be sufficient to complete the rearrangement of particles, and the required time varies depending on the particle size, ultrasonic frequency, water temperature, and the like. However, under normal production conditions, it is preferably performed for 10 seconds to 60 minutes, more preferably 3 minutes to 30 minutes.
Advantages obtained by ultrasonic irradiation include the effect of destroying the soft agglomerates of particles that tend to occur when preparing a nanoparticle dispersion, in addition to the closest packing of particles (to make the random array 6-way closest) This also has the effect of repairing some of the point defects, line defects, or crystal transitions.

The formation of the single particle film described above is due to self-organization of particles. The principle is that when the particles are aggregated, surface tension acts due to the dispersion medium existing between the particles. As a result, the particles do not exist at random, but a two-dimensional close packed structure is automatically used. It is to form. In other words, the close-packing by surface tension can be said to be arrangement by lateral capillary force.
In particular, when three particles, such as colloidal silica, which are spherical and have a highly uniform particle size, come together and come into contact with each other in a floating state on the water surface, the surface of the particle group is minimized so as to minimize the total length of the waterline. Tension acts, and as shown in FIG. 1, the three particles are stabilized in an arrangement based on the equilateral triangle T shown in the figure. If the water line is at the apex of the particle group, that is, if the particles are submerged below the liquid surface, such self-organization does not occur and a single particle film is not formed. Therefore, when one of the particles and the lower layer water is hydrophobic, it is important to make the other hydrophilic so that the particles do not dive under the liquid surface.
As the lower layer water, it is preferable to use water as described above. When water is used, relatively large surface free energy acts, and the close-packed arrangement of particles once generated is stable on the liquid surface. It becomes easy to sustain.

[Transition process]
The single particle film formed on the liquid surface by the single particle film forming step is then transferred onto the substrate which is the object to be etched in the single layer state (transfer step). The substrate may be planar or may include a part or all of a non-planar shape such as a curved surface, an inclination, or a step. Even if the substrate is not flat, the single particle film of the present invention can completely cover the substrate surface while maintaining a two-dimensional close-packed state by causing a crystal plane slip phenomenon during the transition process. Is possible. There is no particular limitation on the specific method for transferring the single particle film onto the substrate. For example, while maintaining the hydrophobic substrate substantially parallel to the single particle film, the single particle film is lowered from above to form the single particle film. A method of transferring and transferring the single particle film to the substrate by the affinity between the single particle film and the substrate, both of which are hydrophobic, and the substrate; before the single particle film is formed, the substrate is approximately horizontal in the lower water of the water tank in advance. There is a method of transferring the single particle film onto the substrate by arranging the single particle film in the direction and gradually lowering the liquid level after forming the single particle film on the liquid surface. According to these methods, the single particle film can be transferred onto the substrate without using a special apparatus. However, even in the case of a single particle film having a larger area, the secondary close packed state It is preferable to adopt the so-called LB trough method in that it can be easily transferred onto a substrate while maintaining the above (Journal of Materials and Chemistry, Vol.11, 3333 (2001), Journal of Materials and Chemistry, Vol.12, 3268) (See 2002).

FIG. 2 schematically shows an outline of the LB trough method. In this method, the substrate is dipped in a substantially vertical direction in the lower layer water in the water tank in advance, and the dropping step and the single particle film forming step are performed in this state to form a single particle film (FIG. 2A). )). After the single particle film formation step, the single particle film F can be transferred onto the substrate by pulling the substrate upward (FIG. 2B). In this figure, the state where the single particle film is transferred to both surfaces of the substrate is shown. However, in the case of producing a fine uneven pattern formed on only one surface such as an antireflection body, single particles are used. The film need only be transferred to one side.
Here, the single particle film has already been formed into a single layer on the liquid surface by the single particle film formation process, so the temperature conditions of the transition process (temperature of the lower layer water), the pulling speed of the substrate, etc. vary slightly However, there is no fear that the single particle film F collapses and becomes multilayered in the transfer step. In addition, the temperature of lower layer water is normally about 10-30 degreeC depending on the environmental temperature which fluctuates with a season or weather.

Further, at this time, as a water tank, a surface pressure sensor (not shown) that measures the surface pressure of the single particle film (operated on the principle of the well-helmy plate) and a single particle film that is compressed in the direction along the liquid surface are omitted. When an LB trough device having a movable barrier is used, a single-particle film having a larger area can be more stably transferred onto the substrate. According to such an apparatus, the single particle film can be compressed to a preferable diffusion pressure (density) while measuring the surface pressure of the single particle film, and can be moved toward the substrate at a constant speed. . Therefore, the transfer of the single particle film from the liquid surface to the substrate proceeds smoothly, and troubles such as the transfer of only a single particle film having a small area onto the substrate hardly occur. A preferable diffusion pressure is 5 to 80 mNm ⁻¹ , more preferably 10 to 40 mNm ⁻¹ . With such a diffusion pressure, it is easy to obtain a single particle film in which each particle is two-dimensionally closely packed with higher accuracy. Further, the speed of pulling up the substrate is preferably 0.5 to 20 mm / min. The temperature of lower layer water is 10-30 degreeC normally as above-mentioned. Note that the LB trough device can be obtained as a commercial product.

(Transition process)
Although the single particle film etching mask can be formed on the substrate by the transfer step, a fixing step for fixing the formed single particle film etching mask on the substrate may be performed after the transfer step. By fixing the single particle film on the substrate, it is possible to suppress the possibility that particles move on the substrate during an etching process described later, and it is possible to perform etching more stably and with high accuracy. In particular, such a possibility increases when the final stage of the etching process in which the diameter of each particle gradually decreases.

As a method of the fixing step, there are a method using a binder and a sintering method.
In the method using a binder, a binder solution is supplied to the single particle film side of the substrate on which the single particle film etching mask is formed, and this is infiltrated between the single particle film etching mask and the substrate.
The amount of the binder used is preferably 0.001 to 0.02 times the mass of the single particle film etching mask. In such a range, the particles can be sufficiently fixed without causing the problem that the binder is too much and the binder is clogged between the particles, and the accuracy of the single particle film etching mask is adversely affected. If a large amount of the binder solution has been supplied, after the binder solution has permeated, the excess of the binder solution may be removed by using a spin coater or tilting the substrate.
As the binder, metal alkoxysilanes, general organic binders, inorganic binders and the like exemplified above as the hydrophobizing agent can be used. After the binder solution has permeated, heat treatment may be appropriately performed depending on the type of the binder. . When using a metal alkoxysilane as a binder, it is preferable to heat-process at 40-80 degreeC on the conditions for 3 to 60 minutes.

  In the case of employing the sintering method, the substrate on which the single particle film etching mask is formed may be heated to fuse each particle constituting the single particle film etching mask to the substrate. The heating temperature may be determined according to the material of the particles and the material of the substrate, but particles having a particle size of 1 μmφ or less start an interfacial reaction at a temperature lower than the original melting point of the material, and thus are heated on a relatively low temperature side. The result is complete. If the heating temperature is too high, the fusion area of the particles increases, and as a result, the shape as a single particle film etching mask may change, which may affect the accuracy. In addition, if heating is performed in air, the substrate and each particle may be oxidized. Therefore, in the etching process described later, it is necessary to set etching conditions in consideration of the possibility of such oxidation. Become. For example, when a silicon substrate is used as a substrate and sintered at 1100 ° C., a thermal oxide layer having a thickness of about 200 nm is formed on the surface of the substrate. In order to avoid the influence of such thermal oxidation, it is preferable to perform sintering in a nitrogen or argon atmosphere.

(Dry etching process)
Thus, the periodic lattice fine structure can be formed on one side of the substrate by subjecting the substrate provided with the single particle film etching mask on one side to vapor phase etching and surface processing (etching process). Specifically, when the gas phase etching is started, first, as shown in FIG. 3A, the etching gas passes through the gaps between the particles constituting the single particle film and reaches the surface of the substrate. Grooves are formed, and a cylinder appears at a position corresponding to each particle. When the gas phase etching is continued, the particles on each cylinder are gradually etched to become smaller, and at the same time, the groove of the substrate becomes deeper (FIG. 3B). Finally, each particle disappears by etching, and a large number of periodic grating protrusions are formed on one side of the substrate (FIG. 3C). In the periodic grating structure of the present invention, the cross-sectional shape as a result of etching may be a pseudo sine wave, a false saw type (triangle), or a false comb shape. A cross-sectional shape may be used (FIGS. 4 and 5).

  The fine structure C thus obtained is used as it is for various displays in personal computers, mobile phones, digital cameras and the like (for example, liquid crystal displays, plasma displays, rear projectors, FCDs such as FEDs and OLEDs), window glass for show windows, etc. It can be used as a viewing angle limiting structure to be applied to surfaces such as exhibition frames, various display windows, optical lenses, optical materials constituting road / traffic signs and signs, and optical members having such a viewing angle limiting structure surface. It can also be used as a master for a nanoimprint mold for production.

Examples of the etching gas used for the vapor phase etching include Ar, SF ₆ , F ₂ , CF ₄ , C ₄ F ₈ , C ₅ F ₈ , C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₆ , and CHF. ₃ , CH ₂ F ₂ , CH ₃ F, C ₃ F ₈ , Cl ₂ , CCl ₄ , SiCl ₄ , BCl ₂ , BCl ₃ , BC ₂ , Br ₂ , Br ₃ , HBr, CBrF ₃ , HCl, CH ₄ , NH ₃ , O ₂ , H ₂ , N ₂ , CO, CO _{2 and the} like can be mentioned, but the invention is not limited to these in order to carry out the gist of the present invention. One or more of these can be used depending on the particles constituting the single particle film etching mask, the material of the substrate, and the like.

As an etching apparatus that can be used in the gas phase etching, a reactive ion etching apparatus, an ion beam etching apparatus, or the like that can generate a bias electric field of about 20 W at the minimum can be used. There are no particular restrictions on the specifications of the chamber structure, the frequency of the high frequency power source, and the like. Since the aspect ratio of the periodic grating structure of the present invention is small, an operation of transferring the particle shape to the substrate is fundamental in the etching process. It is also important to level the surface by etching to reduce the aspect ratio. Etching conditions to achieve such a final shape (particle material constituting single particle film etching mask, substrate material, etching gas type, bias power, antenna power, gas flow rate and pressure, etching time, etc. ) Can be used to create a periodic grating fine structure having a desired aspect ratio. Specifically, for example, a method of performing etching by adjusting the gas composition (SF ₆ + CF ₄ ) so that the etching rates of silicon and silica are the same for colloidal silica particles on a silicon wafer, or on a quartz substrate For the colloidal silica particles, a target shape can be obtained by using CF ₄ gas capable of etching both the substrate and the particles. If the aspect ratio of the periodic grating fine structure of the present invention is too large, the influence of optical scattering will be strong and the surface will appear whitish. Therefore, the aspect ratio of the periodic grating structure of the present invention is 1.0 or less, preferably 0.5 or less, more preferably 0.3 or less.

When the average pitch C of the lattice arrangement of the periodic lattice microstructure thus obtained is determined in the same manner as the above-described method for determining the average pitch B between the particles in the single particle film etching mask, this average pitch C Is substantially the same value as the average pitch B of the used single particle film etching mask. Further, the average pitch C of the array corresponds to the average value of the diameters d of the pseudo circular bottom surfaces of the periodic grating fine protrusions. Further, regarding the periodic grating fine structure, when an alignment shift D ′ (%) defined by the following formula (2) is obtained, the value is also 10% or less.
D ′ [%] = | C−A | × 100 / A (2)
However, in Formula (2), A is an average particle diameter of the particle | grains which comprise the used single particle film etching mask.

[Structure transfer mold and its manufacturing method]
In addition, the periodic grating structure X of the present invention is used as an original plate (master), and a replica is created using at least one of shape transfer techniques such as a nanoimprint method, a press method, an injection molding method, a UV embossing method, and an electroforming method. can do. When manufacturing a mold for transferring a shape of a periodic grating structure, for example, a metal layer is formed on the surface on which the fine structure is formed by plating or the like, and then the metal layer is peeled off to form the fine structure. Is transferred to the metal layer. As a result, a metal layer having a negative pattern with a periodic grating structure on the surface is obtained, and this can be used as a mold for nanoimprinting, pressing, injection molding, UV embossing, electroforming, etc. If it carries out, it will become possible to mass-produce the copy of the periodic grating structure X of this invention efficiently.

  As a method for forming the metal layer of the mold on the surface on which the periodic grating fine structure is formed, a plating method is preferable. Specifically, first, nickel, copper, gold, silver, platinum, titanium, cobalt, tin, Electroless plating with one or more metals selected from zinc, chromium, gold / cobalt alloy, gold / nickel alloy, solder, copper / nickel / chromium alloy, tin / nickel alloy, nickel / palladium alloy, nickel / cobalt / phosphorus alloy, etc. Alternatively, a method in which the thickness of the metal layer is increased by performing vapor deposition or sputtering and then performing electrolytic plating with one or more metals selected from these metals is preferable.

The thickness of the metal layer formed by electroless plating, vapor deposition or sputtering is preferably 10 nm or more, more preferably 100 nm or more. However, the conductive layer generally requires a thickness of 50 nm. When the film thickness is set in this way, unevenness of the current density in the surface to be plated can be suppressed in the subsequent electrolytic plating process, and a mold for shape transfer having a uniform thickness can be easily obtained.
In the subsequent electrolytic plating, it is preferable that the thickness of the metal layer is finally increased to 10 to 3000 μm, and then the metal layer is peeled off from the original plate. Although there is no restriction | limiting in particular in the current density in electroplating, Since bridge | bridging can be suppressed and a uniform metal layer can be formed and such a metal layer can be formed in a comparatively short time, it is 0.03-10A / m. ² is preferred.
In addition, from the viewpoint of wear resistance as a shape transfer mold, reworkability at the time of peeling / bonding, the material of the metal layer is preferably nickel, electroless plating or vapor deposition performed first, and electrolytic plating performed thereafter. It is preferable to employ nickel for both.

[Nanoimprint or injection molding equipment and nanoimprint or injection molding]
According to the nanoimprint method, the press method, the injection molding method, the UV embossing method, the electroforming method and the like having the shape transfer mold thus manufactured, the periodic grating structure is formed with high accuracy and the viewing angle limiting function is improved. Shape transfer bodies (replicas) suitable for expression can be mass-produced with good reproducibility.
Among these shape transfer methods, the nanoimprint method and the injection molding method are particularly suitable for transferring fine shapes. There is no particular limitation on the method of the nanoimprint or injection molding apparatus. The nanoimprint mold is pressed against a heated and softened thermoplastic resin base material, and then the base material is cooled before the nanoimprint mold is attached. A thermal imprint method for transferring a fine pattern formed on the nanoimprint mold to the substrate by separating it from the substrate, pressing the nanoimprint mold against the uncured photocurable resin substrate, Light (UV) imprinting method that transfers the fine pattern formed on the nanoimprinting mold to the substrate by irradiating ultraviolet light to cure the photocurable resin and then separating the nanoimprinting mold from the substrate. The molten resin is injected into the mold at a high pressure, and then the mold is cooled through the process of cooling the entire mold. And mold, injection molding method for transferring a fine pattern formed on the injection molding mold for molding material surface, can be adopted a known method such as.
A thermal imprint nanoimprint apparatus is schematically configured to include a nanoimprint mold having a press means and a temperature control means for controlling the temperature of the substrate, and the optical imprint nanoimprint apparatus has a press means. The nanoimprint mold and an ultraviolet irradiation means for irradiating the substrate with ultraviolet rays are roughly configured. In addition, the injection molding apparatus sets a closed mold in the injection molding machine, and performs the mold clamping, the melting of the plastic material, the pressure injection into the cavity of the closed mold, and the cooling process by the injection molding machine. It is comprised roughly by providing a mechanism.

[Addition of metal thin film layer to periodic grating microstructures]
The periodic grating fine structure of the present invention can enhance the viewing angle limiting function by applying a metal thin film layer to the structure surface by a method such as vacuum deposition, sputtering, or electroless plating. This utilizes the fact that by coating the surface of the fine structure with a metal thin film layer, the amount of reflection of light incident on the fine structure surface from the outside increases and the intensity of the diffracted light obtained increases. Specifically, depending on the type of metal, it is important to form the metal thin film layer with a thickness of about 20 to 30 nm or less, preferably 2 to 20 nm, more preferably 5 to 10 nm. Since the viewing angle limiting structure of the present invention assumes the purpose of preventing peeping, the display content can be seen by people located in front of a display or a show window, etc. It is required to be invisible to the person who is located. (Here, the definition of “front” is ± 5 ° when the vertical direction to the substrate such as a display or a show window is 0 °.) Therefore, the viewing angle limiting structure maintains transparency with respect to the front. Therefore, if the thickness of the metal thin film layer is larger than 20 to 30 nm, the opacity increases and the visibility is lowered. In the case of a display window such as a display, when the emission luminance of the display window itself is high, the visibility can be maintained even if the thickness of the metal thin film layer is increased to some extent. In such a case, it is possible to apply a metal vapor deposition layer to a thickness of about 50 nm.

As described above, since the above-described single particle film etching mask is one in which the particles constituting the single particle film are two-dimensionally closely packed and arranged with high precision, It is possible to manufacture an accurate periodic grating structure and a fine structure that is a master of a shape transfer mold having the same structure. In particular, when a master plate for a nanoimprint or injection mold is manufactured, a nanoimprint or injection mold is manufactured using the master and a nanoimprint or injection molding apparatus including the mold is used. Nanoimprints or injection-molded products can be mass-produced with good reproducibility, which is industrially suitable.

[Example 1]
A 5.0% by mass aqueous dispersion (dispersion) of spherical colloidal silica having an average particle size A of 375.7 nm and a particle size variation coefficient of 4.2% was prepared. The average particle diameter and the coefficient of variation of the particle diameter were determined from peaks obtained by fitting the particle size distribution obtained by the particle dynamic light scattering method to a Gaussian curve.
Next, this dispersion was filtered through a membrane filter having a pore size of 1.2 μmφ, and an aqueous solution of a hydrolyzate of phenyltriethoxysilane having a concentration of 1.0 mass% was added to the dispersion that passed through the membrane filter, and the mixture was heated at about 40 ° C. for 3 hours. Reacted. At this time, the dispersion and the aqueous hydrolysis solution were mixed so that the mass of phenyltriethoxysilane was 0.02 times the mass of the colloidal silica particles.
Next, methyl ethyl ketone having a volume 4 times the volume of the dispersion was added to the dispersion after completion of the reaction and stirred sufficiently to extract the hydrophobized colloidal silica in the oil phase.

Water tank (LB trough device) provided with a hydrophobized colloidal silica dispersion thus obtained, a surface pressure sensor for measuring the surface pressure of the single particle film, and a movable barrier for compressing the single particle film in the direction along the liquid surface The solution was dropped at a drop rate of 0.01 ml / second onto the liquid surface (water used as the lower layer water, water temperature 25 ° C.). In addition, a 4-inch synthetic quartz substrate (thickness: 525 μm) was immersed in a substantially vertical direction in advance in the lower layer water of the water tank.
Then, while irradiating ultrasonic waves (output 300W, frequency 950kHz) from the lower layer water toward the water surface for 10 minutes to promote the two-dimensional closest packing of particles, volatilize methyl ethyl ketone as a solvent of the dispersion, A single particle film was formed.
Next, this single particle film was compressed by a movable barrier until the diffusion pressure became 25 mNm ⁻¹ , and a 4-inch synthetic quartz substrate was pulled up at a speed of 2 mm / min and transferred onto one side of the substrate.
Next, a 1% by mass monomethyltrimethoxysilane hydrolyzate as a binder is infiltrated onto the synthetic quartz substrate on which the single particle film is formed, and then the excess of the hydrolyzate is treated with a spin coater (3000 Cm) for 1 minute. Removed. Then, this was heated at 100 degreeC for 10 minute (s), the binder was made to react, and the synthetic quartz board | substrate with a single particle film etching mask which consists of colloidal silica was obtained.

On the other hand, with respect to this single particle film etching mask, an area of 15 μm × 15 μm was randomly selected to obtain an atomic force microscope image of that portion, and then the FFT image obtained by separating the waveform by Fourier transform. Got. Next, an equatorial profile of the FFT image was obtained, the distance from the 0th order peak to the 1st order peak was obtained, and the reciprocal thereof was further obtained. The inverse is the average pitch B ₁ between the particles in this region.
Such processing is similarly performed for a total of 25 15 μm × 15 μm regions, and average pitches B _{1 to} B ₂₅ in each region are obtained, and an average value thereof is calculated as the average pitch B in the formula (1). . At this time, each region was set so that adjacent regions were separated from each other by about 5 mm to 1 cm.
As shown in Table 1, the calculated average pitch B was 378.2 nm.
Therefore, when the average particle diameter A = 375.7 nm and the average pitch B = 378.2 nm are substituted into the equation (1), the deviation D of the particle arrangement in the single particle film etching mask of this example is shown in Table 1. As shown in the figure, it was 0.67%.

Next, vapor phase etching was performed on the substrate with the single particle film etching mask with an etching gas of CF ₄ = 100%. Etching conditions were an antenna power of 1500 W, a bias power of 50 to 300 W, and a gas flow rate of 30 to 50 sccm.

The fine structure thus obtained had a vertical cross-sectional shape as schematically shown in FIG. The average height d of the periodic grating fine protrusions actually measured from the atomic force microscope image is 93.1 nm, and the average pitch C (circularity) of the arrangement of the periodic grating fine protrusions obtained by the same method as that performed for the single particle film etching mask. The average diameter d) of the bottom surface was 378.1 nm, and the aspect ratio calculated from these was 0.246.
The average height d of the periodic grating fine protrusions was determined as follows. First, an atomic force microscope image was obtained for one region of 3 μm × 3 μm randomly selected in the microstructure, and then a profile that passed through a plurality of vertices of periodic grating fine protrusions was produced. And the average value of the unevenness which appeared there was calculated | required. Such treatment was similarly performed on a total of 25 3 μm × 3 μm regions selected at random, and an average value in each region was obtained. The average height d was obtained by further averaging the average values in the 25 regions thus obtained. On each line, 7-8 protrusions are included.
Then, the displacement D ′ of the arrangement of the conical fine protrusions according to the expression (2) was determined for this fine structure, and it was 0.64%.

The obtained microstructure is used as a master of a nanoimprint mold, Ni electroless plating is performed on the surface on which conical microprojections are formed, a Ni layer having a thickness of about 50 nm is formed, and then an electrode jig is formed. After mounting, electrolytic Ni plating (using nickel sulfamate bath) was performed at a current density of 9.0 to 10.5 A / m ³ . The final Ni layer thickness was adjusted to about 300 μm. After plating, the Ni layer was gently peeled from the microstructure to obtain a nanoimprint mold made of Ni.

  After cutting the prepared mold for nanoimprint to 30mm x 30mm, it is attached to the same size stainless steel plate (double-sided mirror polishing) so that the structural surface is exposed, and for UV curable resin (CAK-01CL, manufactured by Toyo Gosei) Then, exposure at 2.0 J was performed while pressing at a pressure of 2.4 MPa. Thereafter, the resin and the mold were gently peeled, and a nanoimprint product having a thickness of about 1.0 mm was taken out. The surface opposite to the structure surface of the nanoimprint product is flat.

With respect to the structure surface of the obtained nanoimprint product, an aluminum thin film layer was applied to a vacuum degree of 1.0 to 5.0 × 10 ⁻⁶ Torr and a deposition rate of 2.0 to 3 using a vacuum deposition machine (EX-400 manufactured by ULVAC). About 100 kg (10 nm) was applied at 0.0 kg / sec.

  White light from a xenon light source with a luminous flux of 0.5 mm is incident on a nanoimprint product on which a metal thin film layer is deposited at an incident angle of 0 ° ± 90 °. The angle of diffracted light obtained for each incident angle is 0 ° ± Measurements were made in the range of 90 °. The diffracted light was measured for a spectrum in increments of 50 nm in the range of 450 to 750 nm. For the measurement, a scattering / light source measuring device GENESISA / GONIO manufactured by Genesia Co., Ltd. and a USB-2000 spectrometer manufactured by Ocean Optics were used. The measurement results are shown in FIG. 6 (lines in the figure are arranged in the order of 450 → 750 from the bottom). In addition, Table 1 shows the results of evaluating the visibility by visual observation in the front (0 ° ± 5 °) direction.

[Example 2]
Except that the ultrasonic wave (output 300W, frequency 950kHz) is irradiated from the lower layer water to the water surface and the operation for promoting the two-dimensional closest packing of the particles is not performed, the same operation as in Example 1 is performed. A single particle layer mask by LB method and a periodic grating fine structure by dry etching method are manufactured using particles having the same average particle diameter A = 375.7 nm, and then a nano-imprint mold is prepared by Ni electroforming mold. A nanoimprint product was created using In this operation, the average pitch B of the particle mask is 413.9 nm, the average pitch C of the arrangement of the periodic grating microstructures is 414.3 nm, and the deviation of each arrangement is D = 10.2% and D ′ = 10.3%. there were. The height of the periodic grating structure was 114.6 nm. Next, in the same manner as in Example 1, after applying a metal thin film layer of about 100 mm (10 nm) to this microstructure, the result of measuring the diffraction angle of white light rays at each incident angle is shown in FIG. Lines are arranged in the order of 450 → 750 from the bottom). In addition, Table 1 shows the results of evaluating the visibility by visual observation in the front (0 ° ± 5 °) direction.

[Example 3]
A nanoimprint master plate with a periodic lattice microstructure was manufactured in exactly the same manner as in Example 1 except that spherical colloidal silica having an average particle size A of 262.8 nm and a particle size variation coefficient of 6.7% was used for the particle mask. Subsequently, a Ni electroforming mold and its nanoimprint product were prepared. In this operation, the average pitch B of the particle mask is 266.9 nm, the average pitch C of the arrangement of the periodic grating fine structures is 266.7 nm, and the deviation D of each arrangement is 1.56% and D ′ = 1.48%. there were. The height of the periodic grating structure was 64.1 nm. In the same manner as in Example 1, after applying a metal thin film layer of about 100 mm (10 nm) to this microstructure, the result of measuring the diffraction angle of white light rays at each incident angle is shown in FIG. 450, 500 are shown). In addition, Table 1 shows the results of evaluating the visibility by visual observation in the front (0 ° ± 5 °) direction.

[Comparative Example 1]
A nanoimprint master plate with a periodic lattice microstructure was manufactured in exactly the same manner as in Example 1 except that spherical colloidal silica having an average particle size A of 159.0 nm and a particle size variation coefficient of 7.4% was used as the particle mask. Subsequently, a Ni electroforming mold and its nanoimprint product were prepared. In this operation, the average pitch B of the particle mask is 163.4 nm, the average pitch C of the arrangement of the periodic grating fine structures is 164.2 nm, and the deviations D of each arrangement are 2.77% and D ′ = 3.27%. there were. The height of the periodic grating structure was 49.3 nm. In the same manner as in Example 1, after applying a metal thin film layer of about 100 mm (10 nm) to this microstructure, the result of measuring the diffraction angle of white light rays at each incident angle is shown in FIG. Absent). In addition, Table 1 shows the results of evaluating the visibility by visual observation in the front (0 ° ± 5 °) direction.

[Comparative Example 2]
A nanoimprint master plate of a periodic lattice microstructure was manufactured in exactly the same manner as in Example 1 except that spherical colloidal silica having an average particle diameter A of 680.2 nm and a coefficient of variation of particle diameter of 8.9% was used for the particle mask. Subsequently, a Ni electroforming mold and its nanoimprint product were prepared. In this operation, the average pitch B of the particle mask is 692.8 nm, the average pitch C of the array of the periodic grating microstructures is 692.7 nm, and the deviations D of each array are 1.85% and D ′ = 1.84%. there were. The height of the periodic grating structure was 194.5 nm. In the same manner as in Example 1, after applying a metal thin film layer of about 100 mm (10 nm) to this microstructure, the result of measuring the diffraction angle of white light rays at each incident angle is shown in FIG. They are arranged in the order of 450 → 750 from the bottom). In addition, Table 1 shows the results of evaluating the visibility by visual observation in the front (0 ° ± 5 °) direction.

[Comparative Example 3]
A nanoimprint master plate of a periodic lattice microstructure is manufactured in exactly the same manner as in Example 1 except that spherical colloidal silica having an average particle size of 375.7 nm and a particle size variation coefficient of 4.2% is used for the particle mask. Subsequently, a Ni electroforming mold and a nanoimprinted product thereof were prepared. In this operation, the average pitch B of the particle mask is 380.1 nm, the average pitch C of the arrangement of the periodic grating fine structures is 379.9 nm, and the deviation of each arrangement is D = 1.17% and D ′ = 1.12%. there were. The height of the periodic grating structure was 751.8 nm. In the same manner as in Example 1, after applying a metal thin film layer of about 100 mm (10 nm) to this microstructure, the result of measuring the diffraction angle of white light rays at each incident angle is shown in FIG. They are arranged in the order of 450 → 700 from the bottom). In addition, Table 1 shows the results of evaluating the visibility by visual observation in the front (0 ° ± 5 °) direction.

It is a top view which shows typically a single particle film etching mask. It is explanatory drawing about the production method of a single particle film etching mask. It is explanatory drawing about the manufacturing method of the periodic grating structure X, and a last form. It is explanatory drawing about the manufacturing method of the periodic grating structure X, and a last form. It is explanatory drawing about the manufacturing method of the periodic grating structure X, and a last form. FIG. 3 is a diagram schematically showing optical characteristics of the viewing angle limiting structure obtained in Example 1. 6 is a diagram schematically showing optical characteristics of a viewing angle limiting structure obtained in Example 2. FIG. 6 is a diagram schematically showing optical characteristics of a viewing angle limiting structure obtained in Example 3. FIG. It is a figure which shows typically the optical characteristic of the viewing angle restriction | limiting structure obtained by the comparative example 1. FIG. It is a figure which shows typically the optical characteristic of the viewing angle restriction | limiting structure obtained by the comparative example 2. FIG. It is a figure which shows typically the optical characteristic of the viewing angle restriction | limiting structure obtained in the comparative example 3. FIG.

Claims (5)

A two-dimensional image having a viewing angle control function, wherein a single particle film etching mask is disposed on at least one surface of a substrate, and a periodic grating structure X satisfying the following condition is provided by dry etching using the mask. Periodic grating structure.
Periodic grating structure X: the mode pitch C of irregularities is 225 to 415 nm, the mode height d is 10 to 250 nm, and the ratio of the mode height d to the mode pitch C is 1.0 or less 2 Dimensional periodic lattice structure.   The method of disposing the single particle film etching mask is a dropping step of dropping a dispersion liquid in which particles are dispersed in a volatile solvent having a specific gravity smaller than that of water onto a liquid surface of water in a water tank, and volatilizing the solvent. A single particle film forming step of forming a single particle film composed of the particles on a liquid surface of water, a transfer step of transferring the single particle film to a substrate surface, the single particle on a substrate coated with the single particle film 2. The two-dimensional periodic grating structure having a viewing angle control function according to claim 1, comprising a fine processing step of creating a periodic grating structure X by performing fine processing by a dry etching method using a film as a mask.   3. The two-dimensional periodic grating structure according to claim 1, wherein the two-dimensional periodic grating structure X has a viewing angle limiting function of ± 5 to ± 90 ° and has little scattered light. 4. The method according to claim 1, wherein the periodic grating structure X created by at least one of the methods according to claim 1 is used as a master and is duplicated using a shape transfer technique. Dimensional periodic lattice structure.   A metal thin film layer was formed on at least one method selected from a vacuum deposition method, a sputtering method, and an electroless plating method on the structural surface of the periodic grating structure X produced by at least one method of claims 1 to 4. A two-dimensional periodic grating structure having a viewing angle control function.

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