JP2007163519A - Method of manufacturing grid polarizing film, grid polarizing film and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a grid polarizing film which is excellent in polarization separating performance and has a high light transmittance through efficient, inexpensive and convenient processes. <P>SOLUTION: The grid polarizing film is obtained by; forming an alignment film on a substrate; applying a block copolymer made by connecting at least two polymer block chains incompatible to each other to form a resin layer in which phase separation structures of lamella type or cylinder type in the copolymer are arranged side by side in one direction; and forming a Z-layer comprising material Z in which the absolute value of difference between a real part n and an imaginary part κ of a complex refractive index (N=n-iκ) is at least 1.0 on the resin layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a grid polarizing film used in optical communications, optical recording, sensors, image display devices, and the like, and in particular, it is excellent in polarization separation performance and high light efficiency in an efficient and simple process. The present invention relates to a method for producing a grid polarizing film having transmittance.

  A grid polarizer is known as a kind of reflective polarizer. This is an optical component having a grid structure in which a large number of linear metals are arranged in parallel at a constant period. This grid polarizer creates a single polarization because it reflects the polarized light component parallel to the grid metal and transmits the perpendicular polarized light component when the grid structure period is shorter than the wavelength of the incident light. Function as. It has been proposed that this grid polarizer is used as an optical component of an isolator in optical communication, and as a component for increasing light utilization and improving luminance in a liquid crystal display device.

Various methods for producing a grid polarizing film in which a grid structure is formed on a resin film substrate have been proposed.
For example, in Patent Document 1, a metal film is formed on a transparent and flexible substrate, and the substrate and the metal film are stretched below the melting point of the metal film, thereby cracking the metal film in a direction perpendicular to the stretching direction. A method of manufacturing a grid-type polarizing optical element that is generated and forms a structure composed of a metal part having a anisotropic shape and a dielectric part is disclosed.

  Patent Document 2 describes a film having a higher order structure in which crystal parts and amorphous parts are alternately connected, or a film having a higher order structure in which two phases having different glass transition temperatures are alternately connected in the stretching direction. Forming a composite film by forming a conductive thin film on one or both sides, stretching the composite film, and heat-fixing it to form a structure consisting of anisotropic conductive portions and polymer dielectric portions A method of manufacturing a polarizing optical element is disclosed.

JP 2001-74935 A JP 2005-148416 A

According to the study of the present inventor, the polarizing optical element obtained by the manufacturing method disclosed in Patent Document 1 has no regularity in the cracks of the metal thin film, and the metal thin film sometimes peels off from the substrate. For this reason, it has been difficult to obtain a polarizing optical element that sufficiently exhibits polarization separation performance. In addition, the polarizing optical element obtained by the manufacturing method disclosed in Patent Document 2 has low light transmittance, and it has been difficult to sufficiently meet the demand for high luminance such as liquid crystal display devices.
The objective of this invention is providing the method of manufacturing the grid polarizing film which has the high light transmittance which was excellent in polarization | polarized-light separation performance by an efficient and simple process.

When the present inventors used a film having a higher-order structure in which crystal parts and amorphous parts are alternately connected, or a film having a higher-order structure in which two phases having different glass transition temperatures are alternately connected in the stretching direction, cracks occurred. Although it is suitable for relatively regular generation of light, it has been noticed that the light transmittance of the film itself is low because light is scattered by structural defects of the resin.
Therefore, the present inventor has developed a resin in which a lamellar or cylindrical phase separation structure in a block copolymer formed by bonding two or more mutually incompatible polymer block chains is aligned in one plane in a plane. When a Z layer including a material Z having a difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) is 1.0 or more is formed on the layer, the layer made of the material Z Is formed only on one phase of a lamellar or cylindrical phase separation structure aligned in one direction in the plane, and as a result, a fine grid structure can be formed without stretching. The present invention has been completed based on the findings.

Thus, according to the present invention,
(1) A resin layer is formed in which a lamellar or cylindrical phase separation structure in a block copolymer obtained by bonding two or more mutually incompatible polymer block chains is aligned in one plane in a plane. ,
A grid including forming a Z layer including a material Z having an absolute value of a difference between a real part n and an imaginary part κ of a complex refractive index (N = n−iκ) of 1.0 or more on the resin layer. A method for producing a polarizing film.
(2) The block copolymer includes a polymer block chain in which a difference in dry etching resistance ER of each polymer block chain represented by Formula 1 is 0.1 or more,
Formula (1): ER = N / (Nc-No)
(In the formula, N represents the total number of atoms per segment (corresponding to the monomer unit) of the polymer block chain, Nc represents the number of carbon atoms, and No represents the number of oxygen atoms.)
The manufacturing method of the grid polarizing film as described in said (1) which further includes the process of dry-etching the said resin layer.
(3) The block copolymer includes a degradable polymer block chain in which at least one of the polymer block chains is decomposed by irradiation with energy rays.
The manufacturing method of the grid polarizing film as described in said (1) which further includes the process of irradiating an energy ray to the said resin layer.
(4) In the block copolymer, at least one of the polymer block chains is a heat-resistant polymer block chain, and at least one of the rest is a thermally decomposable polymer block chain,
The manufacturing method of the grid polarizing film as described in said (1) which further includes the process of heat-processing B the said resin layer above the decomposition temperature of a thermally decomposable polymer block chain.
(5) The manufacturing method of the grid polarizing film in any one of said (1)-(4) whose resin layer is formed on a base material.
(6) The manufacturing method of the grid polarizing film as described in said (5) including forming the base layer which has a structural period between a base material and a resin layer.

(7) forming a Z layer comprising a material Z having an absolute value of the difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) of 1.0 or more on the substrate;
A resin in which a lamellar or cylindrical phase separation structure in a block copolymer formed by bonding two or more incompatible polymer block chains on the Z layer is aligned in one direction in a plane. Forming a layer,
A method for producing a grid polarizing film, comprising: treating the resin layer; and etching the Z layer.
(8) The block copolymer includes a polymer block chain in which the difference in dry etching resistance ER of each polymer block chain represented by Formula 1 is 0.1 or more,
Formula (1): ER = N / (Nc-No)
(In the formula, N represents the total number of atoms per segment (corresponding to the monomer unit) of the polymer block chain, Nc represents the number of carbon atoms, and No represents the number of oxygen atoms.)
The manufacturing method of the grid polarizing film as described in said (7) whose process of the said resin layer is a dry etching process.
(9) The block copolymer includes a degradable polymer block chain in which at least one of the polymer block chains is decomposed by irradiation with energy rays.
The manufacturing method of the grid polarizing film as described in said (7) whose process of the said resin layer is an energy ray irradiation process.
(10) In the block copolymer, at least one of the polymer block chains is a heat-resistant polymer block chain, and at least one of the rest is a thermally decomposable polymer block chain,
The manufacturing method of the grid polarizing film as described in said (7) whose process of the said resin layer is the heat processing B above the decomposition temperature of a thermally decomposable polymer block chain.
(11) The manufacturing method of the grid polarizing film in any one of said (7)-(10) including forming the base layer which has a structural period between Z layer and a resin layer.

(12) A heat treatment of the resin layer at a temperature not lower than the highest glass transition temperature among the glass transition temperatures of each polymer block chain and not higher than the lowest pyrolysis temperature among the thermal decomposition temperatures of each polymer block chain A The manufacturing method of the grid polarizing film in any one of said (1)-(11) further including doing.
(13) The manufacturing method of the grid polarizing film in any one of said (1)-(12) whose material Z is a metal.
(14) The manufacturing method of the grid polarizing film in any one of said (1)-(13) which is a long thing.

Moreover, according to the present invention,
(15) A grid polarizing film obtained by the production method according to any one of (1) to (14).
(16) A grid polarizing film obtained by the production method according to (14) and having a polarization transmission axis substantially parallel to the width direction is provided.
Furthermore, according to the present invention,
(17) A liquid crystal display device comprising the grid polarizing film according to (15) or (16) is provided.

  The manufacturing method of the grid polarizing film of this invention combines the conventional resin molding method and film forming methods, such as a metal film, on predetermined conditions, and can perform it efficiently and simply. And the grid polarizing film obtained with the manufacturing method of this invention has high light transmittance, can isolate | separate natural light into two types of linearly polarized light, can reflect one side, and can permeate | transmit another side. Furthermore, since it has sufficient flexibility and strength, it is easy to handle when attaching the grid polarizing film to a liquid crystal display device or the like. Further, when the grid polarizing film of the present invention is disposed between the liquid crystal cell of the liquid crystal display device and the backlight device, the light emitted from the backlight can be used effectively and the luminance of the display screen can be improved.

(First manufacturing method)
In the first method for producing a grid polarizing film of the present invention, a lamellar or cylindrical phase separation structure in a block copolymer formed by bonding two or more mutually incompatible polymer block chains is in-plane. A resin layer arranged in one direction is formed, and a material Z in which the absolute value of the difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) is 1.0 or more is formed on the resin layer. Forming a Z layer comprising the same.

In the first production method of the present invention, first, a lamellar or cylindrical phase separation structure in a block copolymer formed by bonding two or more mutually incompatible polymer block chains is unidirectional in a plane. A resin layer arranged in a row is formed.
The block copolymer used to form the resin layer is formed by bonding two or more incompatible polymer block chains. In most polymer block chains, the change in entropy due to mixing is small, so the polymer block chains do not melt together, resulting in an incompatible state. In the case of a block copolymer in which two or more mutually incompatible polymer block chains are bonded, the polymer block chains constituting the block copolymer are incompatible with each other, so that phase separation is attempted. Since they are connected to each other by covalent bonds, they cannot be macroscopically separated, and as a result, a periodic structure (phase separation structure) of about several nm to several hundred nm is formed. The form of the phase separation structure of the simplest AB type binary block copolymer depends on the volume fraction of the polymer block chain, and forms a spherical, cylindrical, gyroidal, or lamellar phase separation structure. Among these phase separation structures, the cylinder type and lamellar type are three-dimensionally anisotropic phase separation structures, and therefore these phase separation structures can be used in the present invention. Examples of the block copolymer include a linear block copolymer, a branched graft copolymer, and a star graft copolymer, depending on the bonding form of the polymer block chains. The block copolymer is obtained by polymerizing the corresponding monomer components in the order of each block by a technique such as radical polymerization, anionic polymerization, cationic polymerization, and living radical polymerization. The block copolymer is prepared by further polymerizing another monomer using a macroinitiator having a polymerization initiator added to the end of the polymer chain, or by adding a reactive group to the end of the polymer chain. It can also be obtained by reacting and bonding macromers. Furthermore, a resin obtained by further chemically modifying a block copolymer synthesized by the above-described method can be used in the present invention.

In the present invention, the block copolymer preferably has a large polarity difference between the incompatible polymer block chains constituting the block copolymer.
The polarity difference can be numerically expressed by a solubility parameter difference (SP value difference). The SP value can be estimated from the molecular structure, and many estimation methods such as the theoretical SP values of Small, Hoy, and Fedors have been proposed. Among them, the theoretical SP value of Fedors is an effective calculation method even for a polymer having a new structure because the parameter of the density of the polymer is unnecessary (Japan Adhesion Association Journal, vol. 22, no. 10, 564-567 (1986) etc.). In the Fedors estimation method, the bond energy and molecular kinetic energy Δei possessed by an atomic group such as atoms or polar groups constituting the polymer, the bond energy and molecular kinetic energy ΣΔei of the repeating unit constituting the polymer, and the polymer The theoretical SP value (unit: (cal / cm ³ ) ^1/2 in the following equation 2) by the occupied volume Δvi of atomic groups such as atoms or polar groups and the occupied volume ΣΔvi of the repeating unit constituting the polymer ).
Formula (2): SP = (ΣΔei / ΣΔvi) ^1/2

For example, the theoretical SP value of polystyrene is estimated to be 14.09 (cal / cm ³ ) ^1/2 , and the theoretical SP value of polymethyl methacrylate is estimated to be 10.55 (cal / cm ³ ) ^1/2 . Therefore, the polarity difference (SP value difference) of the block copolymer composed of polystyrene block chains and polymethylmethacrylate block chains is 3.54 (cal / cm ³ ) ^1/2 .

In the present invention, it is preferable to use a block copolymer having an SP value difference of 0.5 (cal / cm ³ ) ^1/2 or more in terms of Fedors theoretical SP value. The block copolymer having such an SP value difference has an affinity for a material Z having an absolute value of the difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) of 1.0 or more. A large difference occurs between the phases of the polymer block chains, and film formation by vapor deposition or the like is selectively performed on the phase side of the block chains with high affinity. For example, when silver is deposited on a block copolymer composed of polystyrene block chains and polymethylmethacrylate block chains, silver is selectively laminated on the phase of the polystyrene block chains. By such selective lamination, a Z layer (in the above, a silver layer) is formed with a structure derived from a lamellar or cylindrical phase separation structure.

  By adding an additive that changes wettability to one of the polymer block chains, the polarity difference (wetability difference) between the polymer block chains can be increased more than the theoretical SP value difference.

  The block copolymer used in the present invention preferably has a difference in physical resistance between two or more incompatible polymer block chains constituting the block copolymer. If there is a difference in physical resistance between polymer block chains, for example, the polymer block chain having low resistance to light, heat, etc. will be decomposed, and only that part will be removed from the resin layer, resulting in a polymer block with high resistance. Only the chain remains in the resin layer, and a fine uneven shape can be formed.

  Block copolymers with different physical resistances include 1) those containing polymer block chains that have a higher dry etching rate than other polymer block chains, and 2) one of the polymer block chains has energy rays. There are those containing a degradable polymer block chain whose main chain is decomposed by irradiation, and 3) those containing a heat-resistant polymer block chain and a thermally decomposable polymer block chain as the polymer block chain.

1) A block copolymer containing a polymer block chain having a higher dry etching rate than other polymer block chains A block copolymer containing a polymer block chain having a higher dry etching rate than other polymer block chains When the resin layer made of is dry-etched, a fine concavo-convex shape derived from a lamellar or cylindrical phase separation structure can be formed.

The dry etching resistance ER of the polymer block chain can be expressed by Equation 1.
Formula (1): ER = N / (Nc-No)
Here, N is the total number of atoms per segment (corresponding to a monomer unit) of the polymer block chain, Nc is the number of carbon atoms, and No is the number of oxygen atoms. It is shown that the larger the parameter ER, the higher the dry etching rate (the dry etching resistance decreases).

For example, since the monomer unit of polystyrene is C ₈ H ₈ , 16 / (8-0) = 2. Since the monomer unit of polyisoprene is C ₅ H ₈ , 13 / (5-0) = 2.6. Since the monomer unit of polymethyl methacrylate is C ₂ O ₂ H ₈ , 15 / (5-2) = 5. Therefore, in a block copolymer composed of polystyrene block chains and polymethylmethacrylate block chains, the difference in dry etching resistance ER is 3, and the polymer block chains constituting the block copolymer have high dry etching resistance. It shows different things. Judging from ER, it is expected that the dry etching rate of the polymethylmethacrylate block chain is higher than that of the polystyrene block chain. Actually, CF ₄ was allowed to flow at a flow rate of 30 sccm, the pressure was set to 0.01 torr, and a block copolymer composed of polystyrene block chains and polymethylmethacrylate block chains under the conditions of traveling wave 150 W and reflected wave 30 W was obtained. When active ion etching (RIE) is performed, the polymethylmethacrylate block chain exhibits an etching rate that is about 4 ± 0.3 times greater than the polystyrene block chain.

In general, a polymer including an aromatic ring and having a large number of double bonds has a relatively high carbon ratio, and thus the ER is reduced. As can be seen from ER, the dry etching resistance improves as the carbon in the polymer increases (smaller ER), and the dry etching resistance decreases as oxygen increases (larger ER). This can be explained qualitatively as follows. Carbon has low reactivity to radicals and is chemically stable. Therefore, a polymer rich in carbon hardly reacts with various radicals, and etching resistance is improved. On the other hand, since oxygen is highly reactive to radicals, if the amount of oxygen in the polymer is large, the etching rate is high and the etching resistance is low. Furthermore, oxygen radicals are easily generated when oxygen is contained in the polymer. For this reason, for example, when a fluorine-based etching gas such as CF ₄ is used, the F radicals proliferate due to the action of oxygen radicals, and the number of radicals involved in the etching increases, thereby increasing the etching rate. Acrylic polymers have a high oxygen content and few double bonds, so the ER is large and they are easily etched.

That is, specific examples of the block copolymer include an aromatic ring-containing polymer block chain as an etching resistant polymer block chain, and an acrylic polymer block chain or a polyether chain as an easily etched polymer block chain. Alternatively, a block copolymer or a graft copolymer having a polysilane chain can be preferably used.
Examples of the aromatic ring-containing polymer block chain include a polymer block chain obtained by polymerizing at least one monomer selected from vinyl naphthalene, styrene, or a derivative thereof, and examples of the acrylic polymer block chain include polyacrylic polymers. A polymer block chain obtained by polymerizing at least one monomer selected from acrylic acid, methacrylic acid, crotonic acid or derivatives thereof such as acid, polymethyl methacrylate, poly t-butyl methacrylate and the like is used. As the polyether chain, polyalkylene oxide chains such as polyethylene oxide and polypropylene oxide are used, and as the polysilane chain, dialkyl polysilane derivatives such as polydibutylsilane are used.

  Specific examples of combinations of polymer block chains in the block copolymer include polystyrene chain + polymethyl methacrylate chain, polystyrene chain + polyacrylic acid chain, polystyrene chain + polyethylene oxide chain, polystyrene chain + polypropylene oxide chain, polystyrene chain. + Polyphenylmethylsilane chain, polystyrene chain + polydibutylsilane chain, polyvinyl naphthalene chain + polymethyl methacrylate chain, polyvinyl naphthalene chain + polyacrylic acid chain, polyvinyl naphthalene chain + polyethylene oxide chain, polyvinyl naphthalene chain + polypropylene oxide chain, polyvinyl Examples include naphthalene chain + polyphenylmethylsilane chain, polyvinylnaphthalene chain + polydibutylsilane chain, and the like.

As dry etching gas for dry etching, Ar, O ₂ , CF ₄ , H ₂ , C ₂ F ₆ , CHF ₃ , CH ₂ F ₂ , CF ₃ Br, N ₂ , NF ₃ , Cl ₂ , CCl ₄ , HBr, SF ₆ or the like can be used. Etching conditions can be adjusted as appropriate according to the dry etching gas used. The etching gas flow rate is 5 to 200 sccm, the etching gas pressure is 1 to 200 mTorr, the high frequency power is 100 to 20,000 W, and the etching temperature is − It is common to carry out by setting each in the range of about 60 to 90 ° C. The etching process is preferably performed before the step of forming the Z layer.

2) Block copolymer including a degradable polymer block chain in which at least one of the polymer block chains is decomposed by irradiation with energy rays. At least one of the polymer block chains is decomposed by irradiation with energy rays. When a resin layer made of a block copolymer containing a degradable polymer block chain is treated with energy rays, the degradable polymer block chain is decomposed, and the phase of the degradable polymer block chain can be removed. A fine uneven shape derived from a lamellar or cylinder type phase separation structure can be formed.

This block copolymer has a degradable polymer block chain in which a main chain cleavage reaction proceeds by irradiation with energy rays. On the other hand, the remaining polymer block chain is preferably one in which the main chain is three-dimensionally crosslinked by irradiation with energy rays.
Examples of the energy rays include electromagnetic waves such as visible light, ultraviolet rays, X-rays, and electron beams (β rays) or particle beams. Electron beams, X-rays and γ-rays, particularly electron beams and X-rays are preferably used because they penetrate deep inside the resin layer and the irradiation equipment is relatively low in cost. Among these, an electron beam is most preferable from the viewpoint of high decomposition efficiency of the polymer block chain.

  Examples of the polymer block chain in which the main chain is cleaved by ultraviolet irradiation include those in which the main chain is cleaved by a NorrishType 1 reaction such as a poly (phenylisoprobenyl ketone) chain, and polysilane chains such as boridibutylsilane. be able to.

  Polymer block chains that undergo main chain cleavage reaction upon electron beam (β-ray) irradiation include polyolefins such as polypropylene and polyisobutylene, polymethacrylates such as poly-α-methylstyrenes, polymethacrylic acid, and polymethylmethacrylate. Examples include acid esters, polymethacrylamides, polybutene-1-sulfone, polystyrene furphone, polyolefins sulfones such as poly-2-butylene sulfone, polymethylisopropenyl ketone, polymethacrylonitrile and the like. Further, polymethacrylic acid esters into which fluorine is introduced, polyhexafluorobutyl methacrylate, polytetrafluoropropyl methacrylate, or polytrifluoroethyl-α- in which the methyl group at the α-position of the polymethacrylic acid ester is substituted with chlorine. A chloroacrylate etc. are mentioned.

  Polymer block chains that are three-dimensionally cross-linked by electron beam (β-ray) irradiation include polystyrene, polyacrylic acid, polyacrylic esters such as polymethyl acrylate, polyacrylamide, polymethyl vinyl ketone, or glycidyl groups in the side chain And a polymer block chain having a structure that can be easily cross-linked by irradiation with an electron beam such as an epoxy group, a double bond, or a triple bond. In addition, vinylidene fluoride homopolymers and vinylidene fluoride resins such as copolymers of vinylidene fluoride and propylene hexafluoride are also included.

As a degradable polymer block chain that undergoes a main chain scission reaction upon irradiation with X-rays and a crosslinkable block chain that undergoes a cross-linking reaction, basically a main chain scission reaction is caused by electron beam (β-ray) irradiation. The same molecular block chain and polymer block chain that causes a crosslinking reaction can be used.
Furthermore, metal salts such as Ti of polymethacrylic acid, polydimethylmethylene malonate, polychloroacetaldehyde and the like are also used as the degradable polymer block chain. As the crosslinkable polymer block chain, for example, metal salts of polyacrylic acid such as Ba, Pb and Nd, halogen-containing polyvinyl ethers such as chloroethyl vinyl ether, and the like can be used.

As an ultraviolet ray source, a light source such as a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a low-pressure mercury lamp, a carbon arc, a black light, or a metal halide lamp can be used. Further, as the electron beam source, various electron beam accelerators such as a Cockloft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type can be used. . The amount of electron beam irradiation is not particularly limited, but is preferably set to 100 Gy to 10 MGy, more preferably 1 kGy to 1 MGy, and particularly preferably 10 kGy to 200 kGy. When the irradiation amount is small, the degradable polymer block chain is not sufficiently decomposed. When the irradiation amount is too large, the decomposition product of the degradable polymer block chain may be three-dimensionally crosslinked and cured, and the hardly decomposable polymer block chain may be decomposed. Although the acceleration voltage of the electron beam varies depending on the thickness of the resin layer, it is preferably about 20 kV to 2 MV for a thickness of about 10 nm to several tens of μm, and about 500 kV to 10 MV for a thickness of 100 μm or more. Further, a plurality of electron beams having different acceleration voltages may be irradiated, or the acceleration voltage may be changed during the electron beam irradiation.
After the energy beam irradiation, the decomposed polymer block chain phase is preferably removed by a dry etching method, a wet etching method such as solvent cleaning, or a method of volatilizing decomposition products by heat treatment B. The energy beam irradiation is preferably performed before the step of forming the Z layer.

3) Block copolymer in which at least one of the polymer block chains is a heat-resistant polymer block chain and at least one of the rest is a thermally decomposable polymer block chain. At least one of the polymer block chains is highly heat-resistant. The heat decomposable polymer block chain can be selectively removed by heat-treating a resin layer made of a block copolymer in which at least one of the molecular block chain and the rest is a heat decomposable polymer block chain. This makes it possible to form a fine irregular shape derived from a lamellar or cylinder phase separation structure.

In this block copolymer, at least one of the polymer block chains is a heat-resistant polymer block chain, and at least one of the rest is a thermally decomposable polymer block chain.
The difference in thermal decomposition temperature between the thermally decomposable polymer block chain and the heat resistant polymer block chain is usually 10 ° C. or higher, preferably 50 ° C. or higher, more preferably 100 ° C. or higher. Here, the thermal decomposition temperature is a temperature at which the weight is reduced by half when heated at 1 atm and an inert gas stream for 30 minutes.

The thermally decomposable polymer block chain is preferably one in which the main chain is cleaved by heating.
Examples of thermally decomposable polymer block chains include polyethers such as polyethylene oxide and polypropylene oxide, α-polymethylstyrenes, acrylic resins such as polyacrylic acid esters and polymethacrylic acid esters, and polyphthalaldehydes. It is done. Among them, polyethylene oxide, polypropylene oxide, α-polymethylstyrene, acrylic resins, and the like are excellent because a polymer block chain having a narrow molecular weight distribution can be synthesized by living polymerization.

  On the other hand, the heat resistant polymer block chain has a glass transition temperature equal to or higher than the thermal decomposition temperature of the thermally decomposable polymer block chain, or a crosslinking reaction or intramolecular cyclization at a temperature lower than the thermal decomposition temperature of the thermally decomposable polymer block chain It is preferably made of a polymer that reacts to convert to a heat-resistant structure such as a three-dimensional crosslinked structure or a ladder structure.

  Examples of the heat-resistant polymer block chain include a polysilane chain composed of a Si-Si bond chain, a polysiloxane chain, a polyacrylonitrile chain, a polymethacrylonitrile chain, a polyimide chain, a polyaniline derivative chain, a polyparaphenylene derivative chain, And polycyclohexadiene derivatives having a repeating unit represented by the formula: (In Chemical Formula 1, R is an alkyl group, an aryl group, or an aralkyl group which may have a substituent.)

  Among these, a polymer block chain composed of a polyacrylonitrile chain and a polymethacrylonitrile chain that can be polymerized by living and can form a good block copolymer having a narrow molecular weight distribution is preferable.

  In addition, as the heat-resistant polymer block chain, a polymer chain having a site that forms a heat-resistant molecular structure by crosslinking in the side chain or main chain with heat can also be used favorably. For example, those having a perylene skeleton in the side chain or main chain can be suitably used. Further, a polymer chain having a siloxane cluster such as POSS (Polyhedral Oligomeric Silsesquioxane: polysiloxane T8 cube) in the side chain or main chain may be used. For example, a methacrylate T8 cube as shown in Chemical Formula 2 is polymerized. Things are good. (In Chemical Formula 2, R represents H or an alkyl group, aryl group or aralkyl group which may have a substituent, for example, a methyl group, an ethyl group, a butyl group, an isopropyl group, or a phenyl group.)

  Further, as the heat resistant polymer block chain, a polysilane chain may be used. The polysilane chain is not particularly limited as long as it contains a polysilane structure having a repeating unit represented by Chemical Formula 3 at least in part. (In Chemical Formula 3, R1, R2, R3 and R4 each independently represents an optionally substituted alkyl group having 1 to 20 carbon atoms, aryl group or aralkyl group)

The polysilane chain may be a homopolymer or a copolymer, and may have a structure in which two or more kinds of polysilanes are bonded to each other via an oxygen atom, a nitrogen atom, an aliphatic group, or an aromatic group.
These polysilane chains include poly (methylphenylsilane), poly (diphenylsilane), poly (methylchloromethylphenylsilane), poly (dihexylsilane), poly (propylmethylsilane), poly (dibutylsilane), poly (methylsilane) ), Poly (phenylsilane) and the like, and random or block copolymers thereof.

In addition, the polysilane chain is photooxidized by irradiation with ultraviolet rays in air or in an oxygen-containing atmosphere, and the main chain is cleaved or a siloxane bond is generated by insertion of oxygen. This photo-oxidation can significantly change the etching characteristics of the polysilane phase. Further, the heat treatment B after the photo-oxidation causes a crosslinking reaction mainly composed of siloxane bonds to change to a structure similar to SiO ₂ , so that the heat resistance can be improved. In particular, phenylmethylpolysilane is preferable because it easily undergoes crosslinking reaction due to ultraviolet irradiation.

As the silicon-based polymer block chain, a polysiloxane chain may be used in addition to the polysilane chain. It is possible to synthesize a polymer having a small molecular weight distribution from a cyclic oligosiloxane having a polysiloxane chain by a living polymerization method. As the polysiloxane chain, those having an alkoxyl group in the side chain such as poly (di-i-propoxysiloxane) and poly (di-t-butoxysiloxane) are preferable. Such a polysiloxane chain having an alkoxyl group in the side chain is preferable because the heat resistance and mechanical strength are improved by the three-dimensional crosslinking of the alkoxyl groups by a siloxane bond in the presence of an acid catalyst.
Further, it may be a silicon-containing polymer such as poly (pentamethyldisyryl styrene), and these may be preferably formed into a heat resistant structure similar to silicon oxycarbite by ozone oxidation or / and ultraviolet irradiation.

  Specific examples of combinations of heat-resistant polymer block chains and thermally decomposable polymer block chains include polyacrylonitrile chains + polyethylene oxide chains, polyacrylonitrile chains + polypropylene oxide chains, polymethacrylonitrile chains + polyethylene oxide chains, polymethacrylates. Ronitrile chain + polypropylene oxide chain, polymethylphenylsilane chain + polystyrene chain, polymethylphenylsilane chain + α-polystyrene chain, polymethylphenylsilane chain + polymethyl methacrylate, polymethylphenylressilane chain + polyethylene oxide chain, etc. Can be mentioned. In either case, the former indicates a heat-resistant polymer block chain, and the latter indicates a thermally decomposable polymer block chain.

  The heat treatment B is preferably performed at a temperature equal to or higher than the decomposition temperature of the thermally decomposable polymer block chain. By performing the heat treatment B at a temperature equal to or higher than the decomposition temperature of the thermally decomposable polymer block chain, the block chain portion can be removed and a fine shape can be formed. The time of the heat treatment B can be appropriately adjusted depending on the structure of the thermally decomposable polymer block chain and the treatment temperature. The heat treatment B is preferably performed before the step of forming the Z layer.

The block copolymer has a phase separation structure. In the production method of the present invention, a lamellar or cylinder-type phase separation structure is formed in one plane in a plane as the resin layer.
The method for arranging the phase separation structures in one direction in the plane is not particularly limited. For example, a method of applying a solution of the block copolymer on a substrate having orientation, Science, 273, 931-933. (1996) describes a method of controlling the orientation by an electric field, and the method of applying the block copolymer solution on a substrate having orientation is preferable from the viewpoint of productivity.

  The substrate can be selected from glass, transparent resin and the like, and transparent resin is preferable. As a transparent resin, it is preferable that the glass transition temperature of resin is 60-200 degreeC from a viewpoint of workability, and it is more preferable that it is 100-180 degreeC. The glass transition temperature can be measured by differential scanning calorimetry (DSC).

  Specific examples of the transparent resin include polycarbonate resin, polyethersulfone resin, polyethylene terephthalate resin, polyimide resin, polymethyl methacrylate resin, polysulfone resin, polyarylate resin, polyethylene resin, polyvinyl chloride resin, cellulose diacetate, and cellulose triacetate. And alicyclic olefin polymers. Of these, alicyclic olefin polymers are preferred from the viewpoints of transparency, low hygroscopicity, dimensional stability, and processability. Examples of the alicyclic olefin polymer include cyclic olefin random multicomponent copolymers described in JP-A No. 05-310845, US Pat. No. 5,179,171, JP-A No. 05-97978, and US Pat. No. 5,202,388. Examples thereof include the hydrogenated polymers described, the thermoplastic dicyclopentadiene ring-opening polymers described in JP-A-11-124429, and WO99 / 20676, and hydrogenated products thereof.

The transparent resin used in the present invention contains coloring agents such as pigments and dyes, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. An agent may be appropriately blended.
A base material made of a transparent resin can be obtained by molding the transparent resin by a known method. Examples of the molding method include a cast molding method, an extrusion molding method, and an inflation molding method.

The substrate usually has a plate shape, a sheet shape, or a film shape, and preferably has a light transmittance in the visible region of 400 to 700 nm of 80% or more and a smooth surface. Moreover, the average thickness of a base material is 5 micrometers-1 mm normally from a viewpoint of handleability, Preferably it is 20-200 micrometers.
The substrate is a value defined by the retardation Re (Re = d × measured at that wavelength _{550nm (n x -n y),} n x, plane principal refractive index of _{n y} the substrate; d is The average thickness of the base material) is not particularly limited. The difference in retardation Re (retardation unevenness) at any two points in the plane is preferably 10 nm or less, more preferably 5 nm or less. When the retardation unevenness is large, the brightness of the display surface tends to vary when used in a liquid crystal display device.

  In the present invention, a resin layer in which cylinder-type and lamellar-type phase separation structures are arranged in one direction in a plane is used. As a method of arranging the phase separation structures in one direction in the plane, a method of forming an alignment film (underlayer having a structural period) on the substrate in order to give the substrate orientation is preferable. The alignment film is not particularly limited as long as the phase separation structure in the block copolymer can be adjusted in one direction. For example, a random copolymer composed of a general alignment film such as polyimide, polyvinyl alcohol, polyester, polyarylate, polyamideimide, and polyetherimide, and a monomer that constitutes a polymer block chain of a block copolymer that forms a phase separation structure. An alignment film made of a polymer may be mentioned. In particular, from the viewpoint of orientation, an alignment film containing a random copolymer composed of monomers constituting a polymer block chain of a block copolymer forming a phase separation structure is preferable. By using the random copolymer, the surface energy difference at the interface between the polymer block chains forming the alignment film and the block copolymer can be offset, and as a result, the block copolymer forming the phase separation structure can be offset. The orientation of the polymer is greatly improved. The alignment film can be obtained by laminating a coating solution containing a resin as a main component in a film form on a support substrate, drying the film, and then rubbing it in one direction. By rubbing the coating layers laminated in a film in one direction, a periodic structure can be formed on the alignment film, and as a result, an alignment film capable of regulating the alignment of the resin layer in one direction is obtained.

The rubbing method is not particularly limited, and examples thereof include a method of rubbing the alignment film in a fixed direction with a roll made of a synthetic fiber such as nylon or a natural fiber such as cotton or a felt. In order to remove fine powder (foreign matter) generated during rubbing and to clean the surface of the alignment film, it is preferable to clean the formed alignment film with isopropyl alcohol or the like. The characteristic surface roughness of the substrate can be measured with an atomic force microscope (AFM).
The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 1 μm.

  Examples of the method of applying the block copolymer solution include spin coating, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, die coating, and gravure printing. Is mentioned.

  The solvent used for dissolving the block copolymer is not particularly limited. For example, aromatic hydrocarbons such as benzene, toluene and xylene; chain or cyclic aliphatic hydrocarbons such as heptane and cyclohexane; chlorobenzene Halogenated hydrocarbons such as dichlorobenzene, trichlorobenzene and dichloromethane; ethers such as dioxane and diethyl ether; ketones such as cyclohexanone and acetophenone; esters such as ethyl acetate and propiolactone; acetonitrile and benzonitrile Nitriles: alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol; other nitrobenzenes, sulfolanes, and the like. These can be used alone or as a mixture.

  Films obtained by applying a block copolymer solution and drying often exhibit a disordered and thermally unstable structure. This is because in the process of applying and drying the solution, the time required to complete the phase separation process between the components and form an ordered phase separation structure is insufficient. For this reason, after placing the resin layer on the substrate, it is preferable to heat-treat the film as necessary. By this heat treatment A step, the phase separation structure can be further grown. The heat treatment A is the thermal decomposition of the polymer block chain having the lowest thermal decomposition temperature above the glass transition temperature of the polymer block chain having the highest glass transition temperature among the polymer block chains of the block copolymer constituting the resin layer. It is preferable to carry out below the temperature. For example, in a film formed of a block copolymer made of polystyrene and polymethyl methacrylate, the heat treatment A is performed at a temperature of 140 ° C. or higher, more preferably 190 to 230 ° C. for 10 minutes or longer. In order to prevent oxidative deterioration of the block copolymer film due to heating, it is preferable to perform the heat treatment A in an inert atmosphere or vacuum.

  In the present invention, the resin layer may contain additives such as an antioxidant, a photodegradation inhibitor, organic fine particles, inorganic fine particles, a plasticizer and a crosslinking agent. As the additive, it is preferable to use an additive having a specific high affinity with one of the polymer block chains that are phase-separated from each other. In this case, the additive can be easily unevenly distributed in the block phase with good affinity in the process of forming the phase separation structure. As a result, the etching resistance of the phase containing the additive can be improved. In particular, better patterning is possible by making the additive unevenly distributed in the heat resistant phase.

  The average thickness of the resin layer is usually 0.1 to 500 μm, preferably 1 to 50 μm. By setting the average thickness of the resin layer within this range, a grid polarizing film having a high light transmittance can be easily obtained.

  On the formed resin layer, the Z layer may be formed as it is in the next Z layer forming step. However, as described above, the resin layer is subjected to dry etching treatment, energy ray irradiation treatment or heat treatment B, and phase separation is performed. A fine uneven shape derived from the structure can be formed. In the present invention, when the heat treatment A and the heat treatment B are performed, it is preferable to perform the heat treatment B after the heat treatment A is performed.

  In the first production method of the present invention, next, the material Z having an absolute value of the difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) is 1.0 or more on the resin layer. Forming a Z layer comprising The complex refractive index N is a theoretical relational expression of electromagnetic waves, and is expressed by N = n−iκ using the refractive index n of the real part and the extinction coefficient κ of the imaginary part.

  The material Z can be appropriately selected from materials in which either the real part or the imaginary part of the complex refractive index is large and the absolute value of the difference is 1.0 or more. Specific examples of the material Z include metals; inorganic semiconductors such as silicon and germanium; conductive polymers such as polyacetylene, polypyrrole, polythiophene, and poly-p-phenylene; and conductive resins such as iodine, boron trifluoride, and five fluorine. Organic conductive materials doped with dopants such as arsenic phosphide and perchloric acid; organic-inorganic composite conductive materials obtained by drying a solution in which conductive metal fine particles such as gold and silver are dispersed in an insulating resin Materials, etc. Among these, a metal material is preferable from the viewpoints of productivity and durability of the grid polarizing film. In order to efficiently separate polarized light in the visible range, each of the real part n and the imaginary part κ of the complex refractive index at a temperature of 25 ° C. and a wavelength of 550 nm is preferably such that n is 4.0 or less and κ is 3. 0 or more and the absolute value of the difference | n−κ | is 1.0 or more, more preferably n is 2.0 or less, κ is 4.5 or more, and | n−κ | .0 or more. Examples of the preferable range include silver, aluminum, chromium, indium, iridium, magnesium, palladium, platinum, rhodium, ruthenium, antimony, and tin. Examples of the more preferable range include aluminum, indium. , Magnesium, rhodium, tin and the like. In addition to the above, a material in which n is 3.0 or more and κ is 2.0 or less, preferably a material in which n is 4.0 or more and κ is 1.0 or less is also preferably used. be able to. Examples of such a material include silicon.

  The Z layer is preferentially formed on one phase of the phase separation structures arranged in one direction. The method for forming such a Z layer is not particularly limited. Depending on the materials used, various coatings by vacuum deposition processes such as vacuum deposition, sputtering, and ion plating, and wet processes such as microgravure, screen coating, dip coating, electroless plating, and electrolytic plating Can be used. In addition, as described in JP-A-2004-6197, JP-A-2004-303783, JP-A-2005-146308, and JP-A-2005-206925, a complex of an amine compound and alane is applied. In addition, a method of forming aluminum by further heat and / or light treatment can be used. Of these, vacuum deposition and sputtering are preferred.

(Second manufacturing method)
The second manufacturing method of the grid polarizing film of the present invention includes a material Z containing a material Z in which the absolute value of the difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) is 1.0 or more. A lamellar or cylindrical phase separation structure in a block copolymer formed by forming a layer on a substrate and bonding two or more mutually incompatible polymer block chains on the Z layer The method includes forming a resin layer arranged in one direction in the plane, treating the resin layer, and further etching the Z layer.

  The Z layer and its formation method, and the resin layer and its formation method can be performed in the same manner as in the first production method. Before forming the resin layer on the Z layer, it is preferable to form an alignment film (underlayer having a structural period) on the surface of the Z layer. The alignment film and the formation method thereof are the same as the alignment film and the formation method described in the first manufacturing method.

In the second manufacturing method, after the resin layer is formed, the resin layer is processed to form a fine pattern derived from the phase separation structure. Furthermore, by using the obtained fine pattern as a mask and etching the Z layer, a grid structure composed of the Z layer can be obtained.
As a method for treating a resin comprising a block copolymer and a resin layer, the composition and treatment method described in the first production method can be used.
The etching process of the Z layer in the second manufacturing method can use wet etching or dry etching.
Dry etching is not particularly limited, and a conventional method can be used. For _{example, F 2, Cl 2, NF} 3, CF 4, SF 4, SF 6, SiF 4, BF 3, HF, WF 6, MoF 6, PF 3, PF 5, AsF 3 as the etching _gas, AsF 5, BCl ₃ , reactive ion etching (RIE) using C ₅ F ₈ or the like, sputter etching using Ar gas, or the like can be used.
The wet etching is not particularly limited, and a conventional method can be used. For example, a technique using nitric acid, phosphoric acid, a mixture of these acids, or the like as an etchant can be used.

The grid polarizing film obtained by the production method of the present invention has a property of transmitting one of orthogonal linearly polarized light and reflecting the other. By utilizing this property, the luminance of the liquid crystal display device can be improved.
For example, various functions can be provided by superimposing the grid polarizing film obtained by the production method of the present invention on another optical film. Examples of other optical films include an absorbing polarizing film, a retardation element, and a polarizing diffraction element. In particular, when the grid polarizing film of the present invention is used for improving the luminance of a liquid crystal display device, the other optical film is preferably an absorption polarizing film.

  The absorptive polarizing film used in the present invention transmits one of two linearly polarized light intersecting at right angles and absorbs the other. For example, a hydrophilic polymer film such as a polyvinyl alcohol film or an ethylene vinyl acetate partially saponified film adsorbed a dichroic substance such as iodine or a dichroic dye and uniaxially stretched, the hydrophilic polymer film Examples include uniaxially stretched and dichroic substances adsorbed, and polyene oriented films such as polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. The thickness of the absorptive polarizing film is usually 5 to 80 μm.

  The grid polarizing film and the absorption polarizing film are preferably overlapped so that the transmission axis of the grid polarizing film and the transmission axis of the absorption polarizing film are substantially parallel. With such an arrangement, natural light can be efficiently converted into linearly polarized light.

  The method for superimposing the grid polarizing film and another optical film is not particularly limited. For example, while simultaneously pulling out the long grid polarizing film wound in a roll shape and another long polarizing optical film wound in a roll shape from the roll, the grid polarizing film and the other optical film are The method including making it closely_contact | adhere is mentioned. An adhesive may be interposed between the grid polarizing film and another optical film. As a method for bringing the grid polarizing film and another optical film into close contact with each other, there is a method in which the grid polarizing film and the other optical film are pressed together and sandwiched between nips of two parallelly arranged rolls.

  The liquid crystal display device of this invention is equipped with the said grid polarizing film. The liquid crystal display device includes a liquid crystal cell whose polarization transmission axis can be changed by adjusting a voltage, and two absorptive polarizing films arranged so as to sandwich the liquid crystal cell. In order to send light to the liquid crystal cell, a backlight device is provided for the transmissive liquid crystal display device and a reflector is provided for the reflective liquid crystal display device on the back side of the display surface.

  In the transmission type liquid crystal display device of the present invention, when the grid polarizing film of the present invention is disposed between the backlight device and the liquid crystal cell, the light emitted from the backlight device is separated into two linearly polarized light by the grid polarizing film. Then, one linearly polarized light returns in the direction of the liquid crystal cell, and the other linearly polarized light returns in the direction of the backlight device. The backlight device is usually provided with a reflecting plate, and the linearly polarized light returning to the direction of the backlight device is reflected by the reflecting plate and returns to the grid polarizing film again. The returned light is again separated into two polarized light by the grid polarizing film. By repeating this, the light emitted from the backlight device is effectively used. As a result, light such as a backlight can be efficiently used for displaying images on the liquid crystal display device, and the screen can be brightened. In the reflective liquid crystal display device, the screen can be brightened by the same principle.

  Next, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples. Parts and% are based on mass unless otherwise specified.

(Brightness improvement effect measurement)
A light diffusion sheet and the grid polarizing element were sequentially stacked on the light exit surface side of the light guide plate in which the cold cathode tube was disposed on the incident end surface side and the light reflecting sheet was provided on the back surface side, thereby producing a polarized light source device. Further, the absorption type polarizing plate is laminated so that the transmission axis of the absorption type polarizing plate is the same as the transmission axis of the grid polarizing element, and the transmission type TN liquid crystal display element and the absorption type polarizing plate are absorbed under the liquid crystal display element. A liquid crystal display device was manufactured by sequentially arranging the polarizing plates in a direction perpendicular to the transmission axis of the polarizing plate. The front luminance at the time of bright display of the obtained liquid crystal display device was measured using a luminance meter (trade name: BM-7, manufactured by Topcon Corporation).

Production Example 1 (Production of styrene-methyl methacrylate random copolymer)
104 parts of styrene, 100 parts of methyl methacrylate and 5 parts of azobisisobutyronitrile were dissolved in 200 parts of normal butyl acetate to obtain a dropping component.
A four-necked flask equipped with a thermometer, a reflux condenser, and a stirrer was charged with 200 parts of xylene and heated to 100 ° C. with stirring. The dropping component was dropped into the four-necked flask at a constant rate with a dropping funnel over 2 hours, and stirred for another hour after the dropping was completed. Next, an additional catalyst component in which 1.0 part of azobisisobutyronitrile was dissolved in 15 parts of normal butyl acetate was added, and after the addition, the mixture was stirred at a temperature of 100 ° C. for 2 hours to obtain a resin solution.
The obtained resin solution was subjected to removal of xylene, normal butyl ester and other volatile components at a temperature of 180 ° C. and a pressure of 1 kPa or less using a cylindrical concentration dryer (manufactured by Hitachi, Ltd.). The obtained resin was extruded into a strand form from an extruder in a melted state, cooled and pelletized to obtain styrene-methyl methacrylate random copolymer pellets.
The random copolymer obtained had a weight average molecular weight of 30,000 and a molecular weight distribution (Mw / Mn) of 1.89.

Production Example 2 (Production of styrene-methyl methacrylate block copolymer forming a lamellar structure)
The monomers styrene and methyl methacrylate were charged with molecular sieves and activated alumina and allowed to stand for 2 days to remove moisture and inhibitors. Then, what was distilled under reduced pressure was used as a monomer for polymerization. Tetrahydrofuran (THF) as a solvent was dehydrated by adding metal sodium and refluxing for 2 days.
The atmosphere inside the pressurized reactor (made by pressure-resistant glass) is set to 4 atmospheres of argon gas, and the dehydrated THF and the polymerization initiator (sec-butyllithium) are added while flowing argon gas so that outside air does not enter the reactor. did. The reactor was then cooled to -78 ° C with dry ice / ethanol. A small amount of styrene was added to the reactor. After confirming that the reaction solution was orange, the reaction was performed for 30 minutes. A small amount of the reaction solution was extracted and the molecular weight was measured by gel permeation chromatography (GPC). Based on the measured molecular weight value, the additional amount of styrene monomer required to obtain a polystyrene block having the desired molecular weight was calculated. . The amount of styrene determined by this calculation was added to the reactor and allowed to react further for 30 minutes. A small amount of the reaction solution was extracted, and it was confirmed by GPC that the desired molecular weight was obtained.
A small amount of 1,1′-diphenylethylene was added, and then the amount of methyl methacrylate necessary to obtain a block of polymethyl methacrylate having the desired molecular weight was added dropwise and allowed to react for 30 minutes. A small amount of the reaction solution was extracted, and it was confirmed by GPC that the desired molecular weight was obtained. A small amount of methanol was added dropwise to stop the reaction, and the reactor was opened. The reaction solution was dropped into methanol to precipitate a solid, filtered and dried to obtain block copolymer 1.
The weight average molecular weight of the block copolymer 1 was 65,000 for the polystyrene unit, 65,500 for the polymethyl methacrylate unit, and the molecular weight distribution (Mw / Mn) was 1.04. Further, the ER of each polymer block chain of the obtained block copolymer is 2 for the polystyrene unit and 5 for the polymethyl methacrylate unit, and the difference in the ER value of each polymer block chain is 3.
When the phase-separated structure of the obtained block copolymer 1 was measured using a small-angle X-ray scattering device (Nano-Viewer, manufactured by Rigaku Denki), the block copolymer was a block copolymer forming a lamellar structure. there were.

Production Example 3 (Production of Styrene-Methyl Methacrylate Block Copolymer Forming Cylinder Structure)
The polystyrene unit was 22,000, the polymethyl methacrylate unit was 55,000, and the molecular weight distribution (Mw / Mn) was 1.09 by the same operation as in Production Example 2 except that the amount of monomer charged and the polymerization degree were changed. Block copolymer 2 was obtained. Further, the ER of each polymer block chain of the obtained block copolymer is 2 for the polystyrene unit and 5 for the polymethyl methacrylate unit, and the difference in the ER value of each polymer block chain is 3.
Further, when the phase separation structure of the obtained block copolymer 2 was measured using a small-angle X-ray scattering device (Nano-Viewer, manufactured by Rigaku Denki Co., Ltd.), the block copolymer was a block copolymer forming a cylinder structure. It was a coalescence.

Production Example 4 (Production of cis-5,6-bis (pivaloyloxy) -1,3-cyclohexadiene-ethylene oxide block copolymer)
Ethylene oxide as a monomer was dried by passing through a column of calcium hydride, and a small amount of n-butyllithium was added, followed by distillation. Tetrahydrofuran (THF) as a solvent was dehydrated by adding metal sodium and refluxing for 2 days.
Depressurized THF and cis-5,6-bis (pivalloyloxy) -1,3 while making the pressurized reactor (made by pressure glass) into an argon gas atmosphere of 4 atm and flowing argon gas so that outside air does not enter the reactor. -Cyclohexadiene was charged.
Next, after the reactor was cooled to −78 ° C. with dry ice / ethanol, a polymerization initiator (sec-butyllithium) was added to the reactor, and polymerization was carried out by stirring for 2 days. Next, a predetermined amount of ethylene oxide was added and further polymerization was performed. Thereafter, 2 mL of 2-propanol containing a small amount of hydrochloric acid was added to stop the reaction, and the reactor was opened. The reaction solution was concentrated 3 times and dropped into a sufficient amount of petroleum ether to precipitate a polymer. The polymer was separated by filtration and vacuum-dried at room temperature to obtain block copolymer 3.
The weight average molecular weight of the block copolymer 3 is 65,000 units of poly (cis-5,6-bis (pivaloyloxy) -2-cyclohexene-1,4-ylene), 60,000 units of polyethylene oxide, The molecular weight distribution (Mw / Mn) was 1.5.
Further, when the phase separation structure of the block copolymer 3 was measured using a small angle X-ray scattering device (Nano-Viewer, manufactured by Rigaku Denki), the block copolymer was a block copolymer forming a lamellar structure. It was.

Example 1 (Underlayer having structure period → phase separation structure formation → heat treatment A → Z layer formation → protection layer formation)
A primer coating solution was prepared by dissolving 20 parts of the styrene-methyl methacrylate random copolymer obtained in Production Example 1 in 980 parts of toluene. The obtained primer coating solution was applied onto a long transparent resin film (trade name “ZEONOR FILM” ZF-14, manufactured by Nippon Zeon Co., Ltd.) so that the dry film thickness was 2 μm, and then 120 ° C. for 5 minutes. Dried. The formed primer layer was rubbed in parallel with the film flow direction and wound into a roll to obtain a long pre-coated film. When a part of the pre-coated film was cut out and the surface state was observed using a scanning probe microscope (Dimension 3100, manufactured by Nippon Beco Co., Ltd.), a fine uneven shape with a depth of about 5 nm was formed in parallel with the film flow direction. It was. That is, it was confirmed that an underlayer having a structural period was formed.
5 parts of the block copolymer 1 obtained in Production Example 2 was mixed with 995 parts of toluene and completely dissolved to prepare a coating solution. The coating solution is applied to the primer layer side of the long pre-coated film obtained in advance so that the dry film thickness becomes 0.1 μm, and heat treatment A is performed at 130 ° C. for 10 minutes, and it is wound into a roll. Thus, a film having a long phase separation structure was obtained.
A part of the obtained film having a long phase separation structure was cut out, and the surface state was observed using a scanning probe microscope (Dimension 3100, manufactured by Nippon Bico Co., Ltd.). As a result, the polystyrene phase was parallel to the film flow direction. And a polymethylmethacrylate phase were arranged at intervals of about 50 nm.
Next, aluminum is vapor-deposited on a film having a long phase separation structure, and a triacetyl cellulose film is continuously superposed on the surface of the aluminum film, bonded by pressing with a pressure roller, and wound into a roll. Thus, a long grid polarizing film 1 was obtained. The obtained long grid polarizing film was punched into a predetermined shape to obtain a single-wafer grid polarizing element 1. The front luminance of the liquid crystal display device using the grid polarizing element 1 was 181 cd / m ² .

Example 2 (underlying layer having structure period → phase separation structure formation → heat treatment A → etching process → Z layer formation → protection layer formation)
The film having a long phase separation structure obtained in Example 1 was subjected to reactive ion etching (RIE) under the conditions of CF ₄ , 0.01 torr, traveling wave 150 W, and reflected wave 30 W. Under this etching condition, the etching rate of the polymethyl methacrylate phase is four times or more than the etching rate of the polystyrene phase constituting the microphase separation film, and the polymethyl methacrylate phase is selectively etched. When the surface state was observed using a scanning probe microscope (Dimension 3100, manufactured by Nihon Beco), polystyrene phases having a width of about 50 nm and a depth of about 70 nm were arranged at intervals of about 50 nm in parallel with the flow direction of the film. A fine structure was formed.
Next, aluminum is vapor-deposited on the film having a long fine structure, and a triacetyl cellulose film is continuously laminated on the surface of the aluminum film, bonded by pressure bonding with a pressure roller, and further wound into a roll. The long grid polarizing film 2 was obtained. The obtained long grid polarizing film 2 was punched into a predetermined shape to obtain a single-piece grid polarizing element 2. The front luminance of the liquid crystal display device using the grid polarizing element 2 was 203 cd / m ² .

Example 3 (Underlayer having structure period → phase separation structure formation → heat treatment A → electron beam irradiation → Z layer formation → protection layer formation)
The main chain of polymethylmethacrylate was cut by irradiating the entire surface of the film having the long phase separation structure obtained in Example 1 with an electron beam at an acceleration voltage of 50 kV and an irradiation amount of 100 μC / cm ² . Next, the obtained film was immersed in a 3: 7 mixed solution of methyl isobutyl ketone and isopropyl alcohol to remove the polymethyl methacrylate phase. When the surface state was observed using a scanning probe microscope (Dimension 3100, manufactured by Nihon Beco), polystyrene phases having a width of about 50 nm and a depth of about 70 nm were arranged at intervals of about 50 nm in parallel with the flow direction of the film. A fine structure was formed.
Next, aluminum is vapor-deposited on the film having a long fine structure, and a triacetyl cellulose film is continuously laminated on the surface of the aluminum film, bonded by pressure bonding with a pressure roller, and further wound into a roll. The long grid polarizing film 3 was obtained. The obtained long grid polarizing film 3 was punched into a predetermined shape to obtain a sheet grid polarizing element 3. The front luminance of the liquid crystal display device using the grid polarizing element 3 was 200 cd / m ² .

Example 4 (Underlayer having structure period → phase separation structure formation → heat treatment A → heat treatment B → Z layer formation → protection layer formation)
The primer coating solution obtained in Example 1 was applied onto a glass substrate so that the dry film thickness was 2 μm, and then dried at 120 ° C. for 5 minutes. By rubbing the formed primer layer, an alignment film was formed on the glass substrate.
Next, 5 parts of the block copolymer 2 obtained in Production Example 4 and 0.25 part of 4,4′-tetrakis (t-butylperoxycarbonyl) benzophenone, which is a radical generator, were mixed with 995 parts of toluene, and completely mixed. A coating solution was prepared by dissolving in The coating solution was applied to the primer layer side of the glass substrate obtained previously so that the dry film thickness was 0.1 μm, and heat treatment A was performed at 130 ° C. for 10 minutes to obtain a film having a phase separation structure. The block copolymer 3 is a copolymer that forms a lamellar structure.
The film was placed in an oven, and heat treatment B was performed in a nitrogen atmosphere at 150 ° C. for 5 hours, 200 ° C. for 5 hours, and 300 ° C. for 2 hours. When the surface of the film after the heat treatment B was observed using a scanning probe microscope (Dimension 3100, manufactured by Beiko Japan), cis-5,6-bis (pivaloyloxy) -1,3-cyclohexadiene was parallel to the rubbing direction. This formed a structure in which phases of the cross-linking part were aligned.
Subsequently, aluminum was vapor-deposited on the obtained film, and a triacetylcellulose film was further superimposed on the surface of the aluminum film and bonded by pressure bonding with a pressure roller to obtain a grid polarizing element 4. The front luminance of the liquid crystal display device using the obtained grid polarizing element 4 was 190 cd / m ² .

Example 5 (Z layer formation → underlying layer with structure period → phase separation structure formation → heat treatment A → dry etching treatment → wet etching treatment → deposition → protection layer formation)
Aluminum was vapor-deposited on a long transparent resin film (trade name “Zeonor film” ZF-14, manufactured by Nippon Zeon Co., Ltd.).
The film was coated on the aluminum deposition surface of the film using the primer coating solution prepared in Example 1 so that the dry film thickness was 0.1 μm, and then dried at 120 ° C. for 5 minutes. Thereafter, the primer layer was rubbed in parallel to the film flow direction, and further rolled up to obtain a long pre-coated film.

A coating solution was prepared by mixing 5 parts of the block copolymer 2 obtained in Production Example 3 with 995 parts of toluene and completely dissolving it. The coating solution is applied on the long pre-coated film obtained in advance so that the dry film thickness becomes 0.1 μm, heat-treated A at 130 ° C. for 10 minutes, and wound up into a roll shape. A film having a phase-separated structure was obtained.
The obtained film having a long phase separation structure was subjected to reactive ion etching (RIE) under the conditions of CF ₄ , 0.01 torr, traveling wave 150 W, and reflected wave 30 W. Under this etching condition, the etching rate of the polymethyl methacrylate phase is 4 or more with respect to the etching rate of the polystyrene phase constituting the microphase separation film, and the polymethyl methacrylate phase is selectively etched. Next, when the surface state was observed using a scanning probe microscope (Dimension 3100, manufactured by Nippon Beco Co., Ltd.), a polystyrene phase having a width of about 50 nm and a depth of about 70 nm was parallel to the film flow direction at intervals of about 30 nm. Formed a side-by-side structure.

Next, 1000 parts of an etchant having a composition (acid component equivalent concentration 81.6%) composed of 5.2% nitric acid, 73.0% phosphoric acid, 3.4% acetic acid, and the balance water is prepared. And the temperature of the etching solution was adjusted to 33 ° C. The long grid polarizing film 5 is obtained by immersing the film having a long fine structure subjected to the dry etching treatment in the etching tank for 30 seconds, drying at 120 ° C. for 5 minutes, and winding up into a roll. Got. The obtained long grid polarizing film 5 was punched into a predetermined shape to obtain a single-piece grid polarizing element 5. The front luminance of the liquid crystal display device using the grid polarizing element 5 was 204 cd / m ² .

Comparative Example 1
A liquid crystal display device without a grid polarizing element was prepared. The front luminance of the obtained liquid crystal display device was 170 cd / m ² .

Claims (17)

Forming a resin layer in which a lamellar or cylindrical phase separation structure in a block copolymer formed by bonding two or more incompatible polymer block chains is aligned in one plane in a plane;
A grid including forming a Z layer including a material Z having an absolute value of a difference between a real part n and an imaginary part κ of a complex refractive index (N = n−iκ) of 1.0 or more on the resin layer. A method for producing a polarizing film. The block copolymer includes a polymer block chain in which the difference in dry etching resistance ER of each polymer block chain represented by Formula 1 is 0.1 or more,
The manufacturing method of the grid polarizing film of Claim 1 which further includes the process of dry-etching the said resin layer.
Formula (1): ER = N / (Nc-No)
(In the formula, N represents the total number of atoms per segment (corresponding to the monomer unit) of the polymer block chain, Nc represents the number of carbon atoms, and No represents the number of oxygen atoms.) The block copolymer is one in which at least one of the polymer block chains includes a degradable polymer block chain in which a main chain is decomposed by irradiation with energy rays,
The manufacturing method of the grid polarizing film of Claim 1 which further includes the process of energy-beam irradiation processing of the said resin layer. In the block copolymer, at least one of the polymer block chains is a heat-resistant polymer block chain, and at least one of the rest is a thermally decomposable polymer block chain,
The manufacturing method of the grid polarizing film of Claim 1 which further includes the process of heat-processing B the said resin layer above the decomposition temperature of a thermally decomposable polymer block chain.   The method for producing a grid polarizing film according to claim 1, wherein the resin layer is formed on a substrate.   The manufacturing method of the grid polarizing film of Claim 5 including forming the base layer which has a structure period between a base material and a resin layer. Forming a Z layer comprising a material Z having a difference between a real part n and an imaginary part κ of a complex refractive index (N = n−iκ) of 1.0 or more on a substrate;
Resin in which a lamellar or cylindrical phase separation structure in a block copolymer formed by bonding two or more incompatible polymer block chains on the Z layer is aligned in one plane in a plane. Forming a layer,
A method for producing a grid polarizing film, comprising: treating the resin layer; and etching the Z layer. The block copolymer includes a polymer block chain in which the difference in dry etching resistance ER of each polymer block chain represented by Formula 1 is 0.1 or more,
The manufacturing method of the grid polarizing film of Claim 7 whose process of the said resin layer is a dry etching process.
Formula (1): ER = N / (Nc-No)
(In the formula, N represents the total number of atoms per segment (corresponding to the monomer unit) of the polymer block chain, Nc represents the number of carbon atoms, and No represents the number of oxygen atoms.) The block copolymer includes a degradable polymer block chain in which at least one of the polymer block chains is decomposed by energy rays.
The manufacturing method of the grid polarizing film of Claim 7 whose process of the said resin layer is an energy ray irradiation process. In the block copolymer, at least one of the polymer block chains is a heat-resistant polymer block chain, and at least one of the rest is a thermally decomposable polymer block chain,
The manufacturing method of the grid polarizing film of Claim 7 whose process of the said resin layer is the heat processing B above the decomposition temperature of a thermally decomposable polymer block chain.   The manufacturing method of the grid polarizing film in any one of Claims 7-10 including forming the base layer which has a structural period between Z layer and a resin layer.   Heat-treating the resin layer A at a temperature not lower than the highest glass transition temperature among the glass transition temperatures of each polymer block chain and not higher than the lowest pyrolysis temperature among the thermal decomposition temperatures of each polymer block chain. Furthermore, the manufacturing method of the grid polarizing film in any one of Claims 1-11 containing.   The manufacturing method of the grid polarizing film in any one of Claims 1-12 whose material Z is a metal.   The manufacturing method of the grid polarizing film in any one of Claims 1-13 which is a long thing.   The grid polarizing film obtained by the manufacturing method in any one of Claims 1-14.   A grid polarizing film obtained by the manufacturing method according to claim 14 and having a polarization transmission axis substantially parallel to the width direction.   A liquid crystal display device comprising the grid polarizing film according to claim 15 or 16.