JP2012058397A - Wire grid polarizer, manufacturing method therefor and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire grid polarizer having sufficient scratch resistance and optical characteristics, a manufacturing method for the polarizer, and a liquid crystal display device having sufficient luminance and contrast.SOLUTION: A wire grid polarizer 1 comprises: a light transmissive substrate 10; a plurality of thin metallic wires 20 arranged parallel to each other on the light transmissive substrate 10; an inorganic oxide layer 30 covering at least the tops of the thin metallic wires 20; and a fluorine-containing compound layers 32 formed by treating at least the surface of the inorganic oxide layer 30 with a fluorine-containing compound with a radical having reactivity to an inorganic oxide. A liquid crystal display device comprises: a liquid crystal panel holding a liquid crystal layer between a pair of substrates; a backlight unit; and the wire grid polarizer 1.

Description

  The present invention relates to a wire grid polarizer, a manufacturing method thereof, and a liquid crystal display device.

  A wire grid type polarizer is known as a polarizer (also referred to as a polarization element or a polarization separation element) having polarization separation ability in the visible light region, which is used in an image display apparatus such as a liquid crystal display device, a rear projection television, or a front projector. It has been.

  The wire grid polarizer has a structure in which a plurality of fine metal wires are arranged in parallel to each other on a light-transmitting substrate. When the pitch of the fine metal wires is sufficiently shorter than the wavelength of the incident light, the component having an electric field vector orthogonal to the fine metal wires (that is, p-polarized light) in the incident light is transmitted and has an electric field vector parallel to the fine metal wires. (Ie s-polarized light) is reflected.

  In the wire grid type polarizer, the fine metal wires are very fine, so the scratch resistance of the fine metal wires is low. For this reason, the fine metal wires are easily damaged by physical contact with the surface of the wire grid polarizer. In the wire grid type polarizer, even if the fine metal wire is slightly damaged, the performance of the wire grid type polarizer is affected.

  Then, in order to suppress the breakage of the fine metal wires, it has been proposed to cover the fine metal wires with a protective film formed by a CVD method using tetraethoxysilane and oxygen gas (Patent Document 1).

  However, since the protective film is formed by the CVD method, not the PVD method (sputtering method, vacuum deposition method, etc.) in which the high energy target component or evaporated particles collides with the target substrate, the metal thin wire and the protective film The adhesion of the protective film is poor, and the protective film is easily peeled off by physical contact or the like. Therefore, it is necessary to make the protective film relatively thick (about 200 nm). As a result, the protective film easily enters the gaps between the fine metal wires, and the gaps are filled with the protective film and become smaller, so that the optical characteristics of the wire grid polarizer are deteriorated. And if the optical characteristic of a wire grid type polarizer falls, the brightness | luminance and contrast of a liquid crystal display device provided with this wire grid type polarizer will fall.

JP 2009-069382 A

  The present invention provides a wire grid polarizer having sufficient scratch resistance and optical properties, a method for manufacturing the same, and a liquid crystal display device having sufficient brightness and contrast.

The wire grid polarizer of the present invention includes a light transmissive substrate, a plurality of fine metal wires arranged parallel to each other on the light transmissive substrate, and an inorganic oxide layer covering at least the top of the fine metal wires, It has a fluorine-containing compound layer formed by treating at least the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide.
The inorganic oxide layer preferably covers the two side surfaces of the fine metal wires and the top portion sandwiched between them and the surface of the light-transmitting substrate between the fine metal wires.

  The method of manufacturing a wire grid polarizer of the present invention includes a step of forming a plurality of fine metal wires arranged in parallel to each other on a light-transmitting substrate, and a step of forming on the light-transmitting substrate on the side where the metal thin wires are formed. A step of depositing an inorganic oxide to form an inorganic oxide layer, and at least the surface of the inorganic oxide layer is treated with a fluorine-containing compound having a group reactive to the inorganic oxide. And a step of forming a fluorine compound layer.

  The liquid crystal display device of the present invention includes a liquid crystal panel having a liquid crystal layer sandwiched between a pair of substrates, a backlight unit, and the wire grid polarizer of the present invention.

The wire grid polarizer of the present invention has sufficient scratch resistance and optical properties.
According to the method for producing a wire grid polarizer of the present invention, a wire grid polarizer having sufficient scratch resistance and optical properties can be produced.
The liquid crystal display device of the present invention has sufficient luminance and contrast.

It is a perspective view which shows an example of a wire grid type polarizer. It is a perspective view which shows the other example of a wire grid type polarizer. FIG. 3 is a perspective view showing a light transmissive substrate of the wire grid polarizer of FIG. 2. It is a perspective view which shows the other example of a wire grid type polarizer. FIG. 5 is a perspective view showing a light transmissive substrate of the wire grid polarizer of FIG. 4. It is sectional drawing which shows an example of the liquid crystal display device of this invention.

<Wire grid polarizer>
The wire grid polarizer of the present invention includes a light transmissive substrate, a plurality of fine metal wires arranged in parallel to each other on the light transmissive substrate, an inorganic oxide layer covering at least the top of the fine metal wires, and at least an inorganic oxide And a fluorine-containing compound layer formed by treating the surface of the physical layer with a fluorine-containing compound having a group reactive to an inorganic oxide.

(Light transmissive substrate)
The light transmissive substrate is a substrate having light transmittance in the wavelength range of use of the wire grid polarizer. The light transmissive property means that light is transmitted, and the used wavelength range is specifically a range of 400 nm to 800 nm.

  Examples of the material for the light-transmitting substrate include a photo-curing resin, a thermoplastic resin, and glass. A photo-curing resin or a thermoplastic resin is preferable from the viewpoint that ridges can be formed by an imprint method described later. Photocuring resins are particularly preferred because they can form ridges by the printing method and are excellent in heat resistance and durability. As the photocurable resin, a photocurable resin obtained by photocuring a photocurable composition that can be photocured by photoradical polymerization is preferable from the viewpoint of productivity.

  The light transmissive substrate may be a laminate. As this laminated body, what has a base material which consists of a thermoplastic resin, glass etc., and the surface layer which has a protruding item | line which consists of photocuring resin formed in the surface of this base material is mentioned, for example.

  In the present invention, the term “ridge” refers to a portion that rises from the main surface of the light-transmitting substrate and that rises in one direction. The ridges may be made of the same material as the main surface portion of the light transmissive substrate that is integral with the main surface of the light transmissive substrate, or may be made of a light transmissive material different from the main surface portion of the light transmissive substrate. Good. The ridges are preferably integral with the main surface of the light transmissive substrate and made of the same material as the main surface portion of the light transmissive substrate.

  The shape of the cross-section in the direction perpendicular to the length direction and the main surface of the light-transmitting substrate is substantially constant over the length direction, and all of the cross-section shapes of the plurality of ridges are substantially constant. Preferably there is. The cross-sectional shape of the ridges is a shape having substantially the same width from the bottom (the main surface of the light-transmitting substrate) to the top, or a shape in which the width gradually decreases from the bottom to the top. Specific examples of the cross-sectional shape include a rectangle, a triangle, and a trapezoid. The cross-sectional shape may have a curved corner or side (side surface).

  In the present invention, the top portion of the ridge means a portion where the highest cross-sectional portion is continuous in the length direction. The top of the ridge may be a surface or a line. For example, when the cross-sectional shape is rectangular or trapezoidal, the top portion forms a surface, and when the cross-sectional shape is triangular, the top portion forms a line. In the present invention, the surface other than the top of the ridge is referred to as a side surface of the ridge. In addition, the flat part of the groove | channel between two adjacent protruding items is considered not the surface of a protruding item but the main surface of a light-transmitting board | substrate.

(Metal fine wire)
The fine metal wire is formed by patterning a metal layer made of a metal or a metal compound formed on the surface of a flat light-transmitting substrate; a flat portion in which a plurality of ridges are formed between the ridges And a metal layer made of a metal or a metal compound selectively formed on the surface of the ridges of the light-transmitting substrate formed on the surface in parallel with each other at a predetermined pitch.

  The plurality of fine metal wires only need to be formed substantially in parallel, and may not be formed completely in parallel. Moreover, although the line which comprises each metal fine wire is the straight line which is most easy to express optical anisotropy in a plane, it may be a curve or a broken line in the range which an adjacent metal thin wire does not contact.

  When a metal layer is formed on the surface of the ridge, the fine metal wire is composed of a metal layer extending in the length direction of the ridge. The metal layer may cover at least a part of the surface of the ridge. When the cross-sectional shape of the ridge is triangular or trapezoidal, the metal layer preferably completely covers the first side surface of the ridge. At this time, the metal layer may cover part or all of the top of the ridge, or may cover all of the top of the ridge and part or all of the second side surface of the ridge. . Moreover, the metal layer may coat | cover a part of flat part between two adjacent protruding items.

Examples of the metal include simple metals, alloys, metals containing dopants or impurities, and the like. Specifically, aluminum, silver, chromium, magnesium, an aluminum alloy, a silver alloy, and the like can be given.
As the material for the fine metal wire, aluminum, aluminum alloy, silver, chromium, magnesium are preferable from the viewpoint of high reflectivity with respect to visible light, low visible light absorption, and high conductivity. Aluminum, aluminum alloy Is particularly preferred.

(Inorganic oxide layer)
The inorganic oxide layer is a layer covering at least the top of the fine metal wire. From the viewpoint of scratch resistance, the inorganic oxide layer is formed from the two side surfaces of the fine metal wires and the top part sandwiched between them, and the surface of the light-transmitting substrate between the fine metal wires (the fine metal wires are formed among the surfaces of the ridges). It is preferable to cover the surface not covered and the flat portion between the ridges.

  From the viewpoint of optical properties, the inorganic oxide layer is formed with voids (grooves) between the fine metal wires (between ridges). Preferably it is formed.

  Examples of the material for the inorganic oxide layer include silicon oxide, zirconium oxide, tin oxide, titanium oxide, and aluminum oxide. From the point that the wire grid polarizer exhibits high transmittance in a short wavelength region, silicon oxide, oxide Zirconium and tin oxide are preferred, and silicon oxide is particularly preferred from the viewpoint of cost.

(Fluorine compound layer)
The fluorine-containing compound layer is a layer formed by treating the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide, and covers the entire surface of the inorganic oxide layer. . For example, when the fluorine-containing compound is a fluorine-containing compound having a hydrolyzable silyl group and a fluoroalkyl group, which will be described later, the fluorine-containing compound layer is composed of a hydrolysis condensate of the fluorine-containing compound.

  Examples of groups reactive with inorganic oxides include silanol groups and hydrolyzable silyl groups. A hydrolyzable silyl group is particularly preferred from the viewpoint of reactivity with inorganic oxides. The hydrolyzable silyl group is a group in which an alkoxy group, an amino group, a halogen atom, or the like is bonded to a silicon atom, and is a group that can be cross-linked by forming a siloxane bond by hydrolysis. A trialkoxysilyl group, an alkyl dialkoxysilyl group and the like are preferable.

As the fluorine-containing compound, a hydrolyzable silyl group and a fluoroalkyl group (which may have an etheric oxygen atom between carbon-carbon atoms) from the viewpoint of reactivity with inorganic oxides and a low dynamic friction coefficient. Fluorine-containing compounds having are preferred.

The dynamic friction coefficient of the fluorine-containing compound layer is preferably 0.2 or less, more preferably 0.15 or less from the viewpoint of scratch resistance.
The dynamic friction coefficient of the fluorine-containing compound layer is measured according to ASTM D 1894.

<Method for producing wire grid polarizer>
Examples of the method for producing the wire grid polarizer of the present invention include the following method (α) and method (β) depending on the method of forming the fine metal wire.

Method (α): A method having the following steps (I) to (III).
(I) A step of forming a metal layer on the surface of a flat light-transmitting substrate and patterning the metal layer to form a plurality of fine metal wires arranged in parallel to each other.
(II) A step of forming an inorganic oxide layer by vapor-depositing an inorganic oxide on the light-transmitting substrate on the side where the fine metal wires are formed.
(III) A step of forming the fluorine-containing compound layer by treating the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide.

Method (β): A method having the following steps (I ′), (II) and (III).
(I ′) A light-transmitting substrate in which a plurality of ridges are formed on the surface in parallel with each other at a predetermined pitch, and a metal or a metal compound is selectively deposited on the surface of the ridges to be parallel to each other. Forming a plurality of arranged metal layers (metal thin wires);
(II) A step of forming an inorganic oxide layer by vapor-depositing an inorganic oxide on the light-transmitting substrate on the side where the fine metal wires are formed.
(III) A step of forming the fluorine-containing compound layer by treating the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide.

[Method (α)]
(Process (I))
The fine metal wire is formed by forming a metal layer on the surface of a flat light-transmitting substrate and patterning the metal layer.

  A vapor deposition method is mentioned as a formation method of a metal layer. Examples of the vapor deposition method include PVD method or CVD. From the viewpoint of adhesion between the light-transmitting substrate and the fine metal wire and the surface roughness of the fine metal wire, the PVD method (vacuum vapor deposition method, sputtering method, ion plating method, etc.) ) Is preferred, and vacuum deposition is particularly preferred from the viewpoint of cost.

  The patterning is performed by forming a resist pattern on the surface of the metal layer, etching the resist pattern as a mask to remove an excess metal layer, and then removing the resist pattern.

(Process (II))
The inorganic oxide layer is formed by vapor-depositing an inorganic oxide on the light-transmitting substrate on the side where the fine metal wires are formed.

  Examples of the vapor deposition method include a PVD method or a CVD method. From the viewpoint of adhesion between a fine metal wire and an inorganic oxide layer and surface roughness, a PVD method (vacuum vapor deposition method, sputtering method, ion plating method, etc.) is used. A sputtering method is preferable, and a sputtering method is particularly preferable.

(Process (III))
The fluorine-containing compound layer is formed by treating the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide.

As the treatment method, for example, in the case where the fluorine-containing compound is a fluorine-containing compound having a hydrolyzable silyl group and a fluoroalkyl group, the following step (i) can be performed because a uniform and thin fluorine-containing compound layer can be formed. It is preferable to go through ~ (iii).
(I) A step of immersing the light-transmitting substrate on which the fine metal wires and the inorganic oxide layer are formed in a diluted solution of a fluorine-containing compound.
(Ii) A step of rinsing the light transmissive substrate with a solvent after lifting the light transmissive substrate from the diluted solution of the fluorine-containing compound.
(Iii) A step of rinsing the light-transmitting substrate and placing it under high temperature and high humidity conditions to hydrolyze and condense hydrolyzable silyl groups to form a fluorine-containing compound layer.

[Method (β)]
(Process (I '))
Examples of methods for producing a light transmissive substrate include imprint methods (light imprint method, thermal imprint method), lithography methods, and the like, and can increase the area of the light transmissive substrate in that protrusions can be formed with high productivity. The imprint method is preferable from the viewpoint that it can be performed, and the optical imprint method is particularly preferable from the viewpoint that the ridges can be formed with higher productivity and the groove of the mold can be accurately transferred.

  In the optical imprint method, for example, a mold in which a plurality of grooves are formed in parallel with each other at a predetermined pitch by a combination of electron beam drawing and etching is used. This is a method of transferring to a photocurable composition applied on the surface and simultaneously photocuring the photocurable composition.

Specifically, the production of the light-transmitting substrate by the photoimprint method is preferably performed through the following steps (i) to (iv).
(I) The process of apply | coating a photocurable composition to the surface of a base material.
(Ii) A step of pressing a mold in which a plurality of grooves are formed in parallel with each other at a predetermined pitch against the photocurable composition so that the grooves are in contact with the photocurable composition.
(Iii) Light having a plurality of ridges corresponding to the grooves of the mold by irradiating radiation (ultraviolet ray, electron beam, etc.) with the mold pressed against the photocurable composition to cure the photocurable composition. A step of manufacturing a transparent substrate.
(Iv) A step of separating the mold from the light transmissive substrate.
In addition, what integrated the surface layer which has a protruding item | line and a base material may be used as a light-transmitting substrate, and what separated the surface layer which has a protruding item | line from a base material may be used as a light-transmitting substrate. Moreover, after forming a metal layer, you may isolate | separate the surface layer which has a protruding item | line from a base material.

Specifically, the production of the light-transmitting substrate by the thermal imprint method is preferably performed through the following steps (i) to (iii).
(I) A step of forming a transfer film of a thermoplastic resin on the surface of a substrate, or a step of producing a transfer film of a thermoplastic resin.
(Ii) Glass mold temperature (Tg) or melting point (Tm) of the thermoplastic resin so that the groove is in contact with the film to be transferred or the film to be transferred in a mold in which a plurality of grooves are formed in parallel with each other at a constant pitch. A step of producing a light-transmitting substrate having a plurality of ridges corresponding to the grooves of the mold by being pressed against the heated transfer film or transfer film.
(Iii) A step of cooling the light transmissive substrate to a temperature lower than Tg or Tm to separate the mold from the light transmissive substrate.
In addition, what integrated the surface layer which has a protruding item | line and a base material may be used as a light-transmitting substrate, and what separated the surface layer which has a protruding item | line from a base material may be used as a light-transmitting substrate. Moreover, after forming a metal layer, you may isolate | separate the surface layer which has a protruding item | line from a base material.

  Examples of the mold material used for the imprint method include silicon, nickel, quartz glass, and resin. From the viewpoint of transfer accuracy, quartz glass and resin are preferable. Examples of the resin include a fluorine-based resin (ethylene-tetrafluoroethylene copolymer, etc.), a cyclic olefin, a silicone resin, an epoxy resin, an acrylic resin, and the like. From the viewpoint of mold accuracy, a photocurable acrylic resin is preferable. . The resin mold preferably has an inorganic film having a thickness of 2 to 10 nm on the surface from the viewpoint of repeated transfer durability. As the inorganic film, an oxide film such as silicon oxide, titanium oxide, and aluminum oxide is preferable.

  Films made of glass plates (quartz glass plates, non-alkali glass plates, etc.) and resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polydimethylsiloxane, transparent fluororesins, etc.) Etc. When a glass plate is used as the substrate, the imprint method can be performed by a single wafer method, and when a film is used as the substrate, the imprint method can be performed by a roll-to-roll method.

  The fine metal wire is formed by selectively depositing a metal or a metal compound on the surface of the ridge of the light transmissive substrate.

  Examples of the vapor deposition method include PVD and CVD, and vacuum vapor deposition, sputtering, and ion plating are preferable, and vacuum vapor deposition is particularly preferable. As the vapor deposition method, the oblique vapor deposition method by the vacuum vapor deposition method is most preferable because the incident direction of the evaporated particles with respect to the light-transmitting substrate can be controlled and a metal or a metal compound can be selectively deposited on the surface of the ridge.

(Process (II)-(III))
Steps (II) to (III) may be performed in the same manner as steps (II) to (III) in method (α).

<Embodiment of Wire Grid Type Polarizer>
Hereinafter, embodiments of the wire grid polarizer of the present invention will be described with reference to the drawings. The following diagram is a schematic diagram, and an actual wire grid polarizer does not have a theoretical and ideal shape as illustrated. For example, in an actual wire grid polarizer, there are some collapses in the shape of metal fine wires, ridges, and the like.
In addition, each dimension in this invention measured each dimension of three places in the transmission electron microscope (TEM) image of a cross section of a wire grid type polarizer, or an atomic force microscope (AFM) image, and the average value. To do.

[First Embodiment]
FIG. 1 is a cross-sectional view showing a first embodiment of a wire grid polarizer of the present invention. The wire grid polarizer 1 includes a flat light-transmitting substrate 10; a plurality of fine metal wires having a rectangular cross-sectional shape formed on the surface of the light-transmitting substrate 10 in parallel with each other at a predetermined pitch Pp. 20; the two side surfaces of the fine metal wire 20 and the top portion sandwiched between them, and the flat portion 13 of the light-transmitting substrate 10 between the fine metal wires 20, so that a gap is formed in the groove 14 between the fine metal wires An inorganic oxide layer 30 that covers the surface of the inorganic oxide layer; and a fluorine-containing compound layer 32 formed by treating the entire surface of the inorganic oxide layer 30 with a fluorine-containing compound having a group reactive to the inorganic oxide. .

  Pp is the sum of the width Dm of the fine metal wires 20 and the width of the grooves 14 formed between the fine metal wires 20. Pp is preferably 30 to 300 nm, and more preferably 50 to 200 nm. When Pp is 300 nm or less, a high s-polarized reflectance is exhibited, and a high degree of polarization is exhibited even in a short wavelength region of about 400 nm. Moreover, the coloring phenomenon by diffraction is suppressed. Moreover, if Pp is 30 nm or more, high transmittance is exhibited.

The ratio of Dm and Pp (Dm / Pp) is preferably 0.1 to 0.7, and more preferably 0.25 to 0.55. When Dm / Pp is 0.1 or more, a high degree of polarization is exhibited. By setting Dm / Pp to 0.5 or less, coloring of transmitted light due to interference can be suppressed.
Dm is preferably 10 to 100 nm from the viewpoint of easily forming the fine metal wire 20.

  The thickness of the inorganic oxide layer 30 covering the side surface of the fine metal wire 20 (width direction of the fine metal wire 20) Da and the thickness of the fluorine-containing compound layer 32 covering the inorganic oxide layer 30 (width direction of the fine metal wire 20) ) The ratio ((Da + Df) / (Pp-Dm)) of the sum (Da + Df) to Df and the width (Pp-Dm) of the groove 14 is preferably 0.4 or less, and preferably 0.01 to 0.3. More preferred. If (Da + Df) / (Pp−Dm) is 0.4 or less, a sufficient gap is formed in the groove 14 and the optical characteristics become better.

  50-500 nm is preferable and, as for the height Hm of the metal fine wire 20, 100-300 nm is more preferable. When Hm is 50 nm or more, the polarization separation ability is sufficiently high. If Hm is 500 nm or less, the chromatic dispersion is small. Moreover, if Hm is 100-300 nm, it is easy to form the metal fine wire 20.

  5-150 nm is preferable and, as for the thickness (height direction of the metal fine wire 20) Ha of the inorganic oxide layer 30 which coat | covers the top part of the metal fine wire 20, 10-100 nm is more preferable. When Ha is 5 nm or more, the scratch resistance is sufficiently high. If Ha is 150 nm or less, the inorganic oxide layer 30 is easily formed.

  1-30 nm is preferable and, as for the thickness (height direction of the metal fine wire 20) Hf of the fluorine-containing compound layer 32 which coat | covers the inorganic oxide layer 30 which coat | covers the top part of the metal fine wire 20, 1-20 nm is more preferable. If Hf is 1 nm or more, the scratch resistance is sufficiently high. If Hf is 30 nm or less, it is easy to form a uniform and thin fluorine-containing compound layer 32.

  The thickness Hs of the light transmissive substrate 10 is preferably 0.5 to 1000 μm, and more preferably 1 to 40 μm.

(Method for manufacturing wire grid polarizer)
The wire grid polarizer 1 can be manufactured by the method (α) described above.

[Second Embodiment]
(Wire grid polarizer)
FIG. 2 is a cross-sectional view showing a second embodiment of the wire grid polarizer of the present invention. The wire grid polarizer 2 has a plurality of ridges 12 having a rectangular cross-sectional shape on the surface parallel to each other and at a predetermined pitch Pp through flat portions 13 of grooves 14 formed between the ridges 12. The formed light-transmitting substrate 10; a metal fine wire 20 made of a metal layer covering the entire top portion 19 of the ridge 12; two side surfaces of the metal fine wire 20 and a top portion sandwiched between them; An inorganic oxide that covers the first side face 16 and the second side face 18 and the flat portion 13 of the light-transmitting substrate 10 between the ridges 12 so that a gap is formed in the groove 14 between the ridges 12. A layer 30; and a fluorine-containing compound layer 32 formed by treating the entire surface of the inorganic oxide layer 30 with a fluorine-containing compound having a group reactive to the inorganic oxide.

  Pp is the sum of the width Dp of the ridges 12 and the width of the grooves 14 formed between the ridges 12. Pp is preferably 30 to 300 nm, and more preferably 50 to 200 nm. When Pp is 300 nm or less, a high s-polarized reflectance is exhibited, and a high degree of polarization is exhibited even in a short wavelength region of about 400 nm. Moreover, the coloring phenomenon by diffraction is suppressed. Moreover, if Pp is 30 nm or more, high transmittance is exhibited.

The ratio of Dp to Pp (Dp / Pp) is preferably 0.1 to 0.7, and more preferably 0.25 to 0.55. If Dp / Pp is 0.1 or more, a high degree of polarization is exhibited. By setting Dp / Pp to 0.5 or less, coloring of transmitted light due to interference can be suppressed.
Dp is preferably 10 to 100 nm from the viewpoint of easily forming a metal layer by vapor deposition.

  10-100 nm is preferable and, as for the width | variety Dm of the metal fine wire 20 (metal layer), 20-80 nm is more preferable. If Dm is 10 nm or more, the polarization separation ability is sufficiently high. If Dm is 100 nm or less, the transmittance is sufficiently high.

  The thickness of the inorganic oxide layer 30 covering the side surface of the ridge 12 (width direction of the ridge 12) Da and the thickness of the fluorine-containing compound layer 32 covering the inorganic oxide layer 30 (width direction of the ridge 12) ) The ratio ((Da + Df) / (Pp-Dp)) of the sum (Da + Df) to Df and the width (Pp-Dp) of the groove 14 is preferably 0.4 or less, 0.01 to 0.3 Is more preferable. If (Da + Df) / (Pp−Dp) is 0.4 or less, a sufficient gap is formed in the groove 14 and the optical characteristics become better.

  50-500 nm is preferable and, as for the height Hp of the protruding item | line 12, 100-300 nm is more preferable. If Hp is 50 nm or more, the polarization separation ability is sufficiently high. If Hp is 500 nm or less, the wavelength dispersion of transmittance can be reduced. Moreover, if Hp is 50-500 nm, it will be easy to form a metal layer by vapor deposition.

  30-500 nm is preferable and, as for the height Hm of the metal fine wire 20 (metal layer), 30-300 nm is more preferable. If Hm is 30 nm or more, the polarization separation ability is sufficiently high. If Hm is 500 nm or less, the wavelength dispersion of the transmittance becomes small. Moreover, if Hm is 30 to 300 nm, it is easy to form a metal layer.

  5-150 nm is preferable and, as for the thickness (height direction of the protruding item | line 12) Ha of the inorganic oxide layer 30 which coat | covers the top part of the metal fine wire 20, 10-100 nm is more preferable. When Ha is 5 nm or more, the scratch resistance is sufficiently high. If Ha is 150 nm or less, the inorganic oxide layer 30 is easily formed.

  1-30 nm is preferable and, as for the thickness (height direction of the protruding item | line 12) Hf of the fluorine-containing compound layer 32 which coat | covers the inorganic oxide layer 30 which coat | covers the top part of the metal fine wire 20, 1-20 nm is more preferable. If Hf is 1 nm or more, the scratch resistance is sufficiently high. If Hf is 30 nm or less, it is easy to form a uniform and thin fluorine-containing compound layer 32.

  The thickness Hs of the light transmissive substrate 10 is preferably 0.5 to 1000 μm, and more preferably 1 to 40 μm.

(Method for manufacturing wire grid polarizer)
The wire grid polarizer 2 can be manufactured by the method (β) described above.

As shown in FIG. 3, the fine metal wires 20 are substantially orthogonal to the length direction L of the ridges 12 and 20 to 50 on the second side surface 18 side with respect to the height direction H of the ridges 12. the metal or metal compound from a direction V2 which forms a an angle theta ^L, the amount of deposition can be formed by depositing the condition to be 15 to 100 nm.

Angle theta ^L, for example, can be adjusted by using the following vapor deposition apparatus.
Substantially perpendicular to the length direction L of the ridge 12, and the vapor deposition source is positioned on an extension of a direction V2 at an angle theta ^L on the side of the second side surface 18 with respect to the height direction H of the ridge 12 The vapor deposition apparatus which can change the inclination of the transparent substrate 10 arrange | positioned facing a vapor deposition source.

[Third Embodiment]
(Wire grid polarizer)
FIG. 4 is a perspective view showing a third embodiment of the wire grid polarizer of the present invention. The wire grid polarizer 3 has a plurality of ridges 12 having a trapezoidal cross section on the surface in parallel with each other through a flat portion 13 of a groove 14 formed between the ridges 12 at a predetermined pitch Pp. The formed light-transmitting substrate 10; the first metal layer 22 covering the entire first side surface 16 of the ridge 12; and the first portion closer to the top portion 19 than the half of the height of the ridge 12. A fine metal wire 20 comprising a surface of the metal layer 22 and a second metal layer 24 covering the top portion 19 of the ridge 12; a side surface and a top portion of the fine metal wire 20; a second side surface 18 of the ridge 12; An inorganic oxide layer 30 that covers the flat portion 13 of the light-transmitting substrate 10 between the strips 12 so that voids are formed in the grooves 14 between the ridges 12; and the entire surface of the inorganic oxide layer 30 is inorganic. Fluorine-containing compounds formed by treatment with fluorine-containing compounds having groups reactive to oxides And a Tsu-containing compound layer 32.

  Pp is the sum of the width Dpb of the bottom of the ridge 12 and the width of the flat portion 13 of the groove 14 formed between the ridges 12. Pp is preferably 30 to 300 nm, and more preferably 50 to 250 nm. When Pp is 300 nm or less, a high surface s-polarized reflectance is exhibited, and a high degree of polarization is exhibited even in a short wavelength region of about 400 nm. Moreover, if Pp is 30 nm or more, high transmittance is exhibited.

The ratio of Dpb to Pp (Dpb / Pp) is preferably 0.1 to 0.7, and more preferably 0.25 to 0.55. When Dpb / Pp is 0.1 or more, a high degree of polarization is exhibited. By setting Dpb / Pp to 0.5 or less, coloring of transmitted light due to interference can be suppressed.
Dpb is preferably 10 to 100 nm from the viewpoint of easily forming each layer by vapor deposition.

  The width Dpt of the top portion 19 of the ridge 12 is preferably not more than half of Dpb, more preferably not more than 40 nm, and still more preferably not more than 20 nm. If Dpt is less than or equal to half of Dpb, the p-polarized light transmittance is higher and the angle dependency is sufficiently low.

  The maximum value Dm1 of the thickness (in the width direction of the ridge 12) from the half of the height of the ridge 12 to the top 19 (the upper half of the ridge 12) of the fine metal wire 20 is preferably 80 nm or less, -75 nm is more preferable, 35-55 nm is still more preferable, and 40-50 nm is especially preferable. If Dm1 is 20 nm or more, the surface s-polarized reflectance is sufficiently high. If Dm1 is 80 nm or less, the p-polarized light transmittance is sufficiently high.

  The maximum value Dm2 of the thickness (width direction of the ridge 12) of the metal thin wire 20 from the half of the height of the ridge 12 to the bottom (lower half of the ridge 12) is preferably 4 to 25 nm. More preferably, it is ˜22 nm. If Dm2 is 4 nm or more, the back surface s-polarized reflectance is sufficiently low. If Dm2 is 25 nm or less, the p-polarized light transmittance is sufficiently high.

  The ratio (Dm1 / (Pp-Dpb)) between Dm1 and the width of the groove 14 (Pp-Dpb) is preferably 0.2 to 0.5. If Dm1 / (Pp-Dpb) is 0.2 or more, the s-polarized light transmittance is lowered, the polarization separation ability is sufficiently high, and the chromatic dispersion is small. If Dm1 / (Pp-Dpb) is 0.5 or less, high p-polarized light transmittance is exhibited.

  The ratio of Dm1 and Dm2 (Dm1 / Dm2) is preferably 2.5 to 10, and more preferably 3 to 8. If Dm1 / Dm2 is 2.5 or more, the polarization separation ability is sufficiently high, and the chromatic dispersion is small. When Dm1 / Dm2 is 10 or less, high p-polarized light transmittance is exhibited.

  Thickness (in the width direction of the ridge 12) Da of the inorganic oxide layer 30 covering the side surface of the ridge 12 (or the metal thin wire 20) Da and thickness of the fluorine-containing compound layer 32 covering the inorganic oxide layer 30 ( The ratio ((Da + Df) / (Pp-Dpb)) of the sum (Da + Df) to the width (Pp−Dpb) of the groove 14 (width direction of the ridge 12) Df is preferably 0.4 or less, 0 0.01 to 0.3 is more preferable. If (Da + Df) / (Pp-Dpb) is 0.4 or less, a sufficient gap is formed in the groove 14 and the optical characteristics become better.

  120-300 nm is preferable and, as for the height Hp of the protruding item | line 12, 80-270 nm is more preferable. If Hp is 120 nm or more, the polarization separation ability is sufficiently high. If Hp is 300 nm or less, the chromatic dispersion is small. Moreover, if Hp is 120-300 nm, it is easy to form the metal fine wire 20 by vapor deposition.

  Regarding the height Hm2 of the thin metal wire 20 located below the top portion 19 of the ridge 12 (on the light-transmitting substrate 10 side), Hm2 / Hp is preferably 0.8 to 1, and more preferably 0.9 to 1. If Hm2 / Hp is 1 or less, the polarization separation ability is improved. If Hm2 / Hp is 0.8 or more, the back surface s-polarized reflectance is sufficiently low.

 Regarding the height Hm1 of the thin metal wire 20 located above the top portion 19 of the ridge 12 (on the side opposite to the light-transmitting substrate 10), Hm1 / Hp is preferably 0.05 to 0.7, preferably 0.1 to 0. .5 is more preferred. If Hm1 / Hp is 0.7 or less, the back surface s-polarized reflectance is sufficiently low. If Hm1 / Hp is 0.05 or more, the surface s-polarized reflectance is sufficiently high.

  5-150 nm is preferable and, as for the thickness (height direction of the protruding item | line 12) Ha of the inorganic oxide layer 30 which coat | covers the top part of the metal fine wire 20, 10-100 nm is more preferable. When Ha is 5 nm or more, the scratch resistance is sufficiently high. If Ha is 150 nm or less, the inorganic oxide layer 30 is easily formed.

  1-30 nm is preferable and, as for the thickness (height direction of the protruding item | line 12) Hf of the fluorine-containing compound layer 32 which coat | covers the inorganic oxide layer 30 which coat | covers the top part of the metal fine wire 20, 1-20 nm is more preferable. If Hf is 1 nm or more, the scratch resistance is sufficiently high. If Hf is 30 nm or less, it is easy to form a uniform and thin fluorine-containing compound layer 32.

The inclination angle θ1 of the first side surface 16 and the inclination angle θ2 of the second side surface 18 are preferably 30 to 80 °. θ1 and θ2 may be the same or different.
The thickness Hs of the light transmissive substrate 10 is preferably 0.5 to 1000 μm, and more preferably 1 to 40 μm.

(Method for manufacturing wire grid polarizer)
The wire grid polarizer 3 can be manufactured by the method (β) described above.

As shown in FIG. 5, the first metal layer 22 is substantially orthogonal to the length direction L of the ridges 12 and on the first side face 16 side with respect to the height direction H of the ridges 12. It can be formed by performing a step (1R1) of depositing a metal or a metal compound from a direction V1 forming an angle θ ^R1 (°) that satisfies the following formula (a).
tan (θ ^R1 ± 10) = (Pp−Dpb / 2) / Hp (a).

The angle θ ^R1 (°) in the formula (a) represents an angle for depositing a metal or a metal compound up to the surface on the bottom side of the ridge 12 without being blocked by the adjacent ridge 12. It is determined from the distance (Pp−Dpb / 2) from the bottom surface to the center of the bottom of the adjacent ridge 12 and the height Hp of the top of the adjacent ridge 12. “± 10” is a swing width.
The angle θ ^R1 (°) preferably satisfies tan (θ ^R1 ± 7) = (Pp−Dpb / 2) / Hp, and satisfies tan (θ ^R1 ± 5) = (Pp−Dpb / 2) / Hp. It is more preferable.

The vapor deposition is preferably performed under the condition that the amount of vapor deposition is 4 to 25 nm, and more preferably under the condition of 5 to 22 nm. The deposition may be performed by continuously changing the angle θ ^R1 (°) within a range satisfying the expression (a) under the condition that the total deposition amount is 4 to 25 nm. When the angle θ ^R1 (°) is continuously changed, it is preferable to change the angle in the direction of decreasing the angle.
The condition for the deposition amount to be 4 to 25 nm is that the metal layer formed by depositing a metal or a metal compound on the surface of a flat portion where no projection is formed when the coating layer is formed on the projection. The conditions are such that the thickness t is 4 to 25 nm.

After the step (1R1), the second metal layer 24 is substantially perpendicular to the length direction L of the ridges 12 and the height direction H of the ridges 12 as shown in FIG. A step (1R2) of depositing a metal or a metal compound on the side surface 16 side of 1 from a direction V1 forming an angle θ ^R2 (°) satisfying the following formula (b) under a condition that the deposition amount is larger than that in the step (1R1) It can be formed by carrying out.
θ ^R1 + 3 ≦ θ ^R2 ≦ θ ^R1 +30 (b).
The angle θ ^R2 (°) preferably satisfies θ ^R1 + 6 ≦ θ ^R2 ≦ θ ^R1 +25, and more preferably satisfies θ ^R1 + 10 ≦ θ ^R2 ≦ θ ^R1 +20.

Vapor deposition is preferably performed under conditions that result in a larger amount of deposition than in step (1R1) and under conditions where the amount of deposition is 25 to 70 nm, and more preferably under conditions that result in 30 to 60 nm. The deposition may be performed by continuously changing the angle θ ^R2 (°) within a range satisfying the formula (b) under the condition that the total deposition amount is 25 to 70 nm. When the angle θ ^R2 (°) is continuously changed, it is preferable to change the angle in the direction of decreasing the angle.

[Other Embodiments]
The wire grid polarizer of the present invention includes a light transmissive substrate, a plurality of fine metal wires arranged in parallel to each other on the light transmissive substrate, an inorganic oxide layer covering at least the top of the fine metal wires, and at least an inorganic oxide As long as the surface of the physical layer has a fluorine-containing compound layer formed by treating with a fluorine-containing compound having a group reactive to inorganic oxides, it is not limited to the examples shown in the drawings. .
For example, you may have a 2nd inorganic oxide layer (aluminum oxide etc.) between a transparent substrate and a metal fine wire.
Further, the inorganic oxide layer may have a laminated structure including a plurality of the same or different inorganic oxide layers.

(Function and effect)
Since the wire grid polarizer of the present invention described above has an inorganic oxide layer that covers at least the top of the fine metal wires, it is possible to suppress peeling of the fine metal wires from the light-transmitting substrate. In addition, since it has a fluorine-containing compound layer formed by treating at least the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide, the dynamic friction coefficient of the surface can be kept low. The peeling of the inorganic oxide layer from the fine metal wire due to physical contact or the like can be suppressed. As a result, a wire grid polarizer having sufficient scratch resistance is obtained. Moreover, since it has a fluorine-containing compound layer, an inorganic oxide layer can be made comparatively thin. As a result, a sufficient gap can be formed in the groove between the fine metal wires (projections), and the deterioration of the optical characteristics can be suppressed.

<Liquid crystal display device>
The liquid crystal display device of the present invention includes a liquid crystal panel having a liquid crystal layer sandwiched between a pair of substrates, a backlight unit, and the wire grid polarizer of the present invention.

  The wire grid polarizer of the present invention is preferably disposed between the liquid crystal panel and the backlight unit, and may be integrated with the substrate on the backlight unit side of the pair of substrates of the liquid crystal panel. Of the pair of substrates of the liquid crystal panel, they may be arranged on the liquid crystal layer side of the substrate on the backlight unit side, that is, inside the liquid crystal panel.

  The liquid crystal display device of the present invention preferably has an absorptive polarizer on the surface of the liquid crystal panel opposite to the side on which the wire grid polarizer of the present invention is disposed, from the viewpoint of thinning.

  FIG. 6 is a cross-sectional view showing an example of the liquid crystal display device of the present invention. The liquid crystal display device 40 includes a liquid crystal panel 44 having a liquid crystal layer 43 sandwiched between a pair of substrates 41 and 42, a backlight unit 45, and a surface on the side where the fine metal wires are formed. The wire grid polarizer 1 of the present invention attached to the surface of the liquid crystal panel 44 on the backlight unit 45 side so that the surface on which the fine line is not formed becomes the viewing side of the liquid crystal display device 40, and the backlight An absorption polarizer 46 is attached to the surface of the liquid crystal panel 44 opposite to the unit 45 side.

  The liquid crystal display device of the present invention described above has sufficient luminance and contrast because it has the wire grid polarizer of the present invention having sufficient scratch resistance and optical characteristics.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Example 1 is an example, and examples 2 and 3 are comparative examples.

(Abrasion resistance)
A wire grid type polarizer was set in a reciprocating wear tester (manufactured by KT Corporation). A wire grid with a load of 50 g, 100 g or 200 g, speed: 140 cm / min, by winding a nell cloth (No. 300) moistened with ethanol around the tip of a cylindrical metal rod having a diameter of 10 mm The surface of the mold polarizer on which the fine metal wires were formed was rubbed 20 times. About the wire grid type | mold polarizer after a test, the total light transmittance was measured with the haze meter (the Toyo Seiki Co., Ltd. make, HAZE-GARDII) under a commercial polarizing plate and crossed Nicols, and light leak (DELTA) T was calculated | required.

(Dynamic friction coefficient)
A smooth cured film having the same laminated structure as that of the wire grid polarizer and having no fine structure was set on a surface property tester (HEIDON-14S manufactured by Shinto Kagaku Kogyo Co., Ltd.). Using a flat indenter, a friction resistance test was performed on a smooth surface under conditions of a vertical load of 200 g and a sliding speed of 100 mm / min, and a dynamic friction coefficient was determined according to ASTM D 1894.

(Preparation of photocurable resin composition)
To a 300 mL four-necked flask equipped with a stirrer and a condenser,
60 g of monomer 1 (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-DPH, dipentaerythritol hexaacrylate),
40 g of monomer 2 (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-NPG, neopentyl glycol diacrylate),
4.0 g of photopolymerization initiator 1 (manufactured by Ciba Specialty Chemicals, IRGACURE907),
Put. In a state where the inside of the flask was kept at room temperature and light-shielded, the mixture was stirred and homogenized for 1 hour to obtain a photocurable resin composition having a viscosity of 140 mPa · s.

[Example 1]
A wire grid polarizer 2 as shown in FIG. 2 was manufactured by the following procedure.

(Process (I '))
A photocurable resin composition is applied to the surface of a highly transmissive polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., Cosmo Shine A4300, 100 mm × 100 mm × thickness 100 μm) by spin coating, and photocured to a thickness of about 5 μm. A coating film of the conductive resin composition was formed.

  Next, the PET film with a coating film was pressed at 25 ° C. using a rubber roll so that the coating film of the photocurable resin composition was in contact with the mold groove, to a nanoimprint mold having a plurality of grooves formed on the surface. It was.

  While maintaining this state, the PET film side was irradiated with light of a high pressure mercury lamp (frequency: 1.5 kHz to 2.0 kHz, main wavelength light: irradiation energy at 255 nm, 315 nm and 365 nm, 365 nm: 1000 mJ) for 15 seconds, After the curable resin composition is cured, the nanoimprint mold is slowly separated, and the light-transmitting substrate 10 having a plurality of ridges corresponding to the grooves of the nanoimprint mold (ridge pitch Pp: 140 nm, ridges) Width Dp: 40 nm, height of protrusions Hp: 200 nm).

  Aluminum was vapor-deposited on the ridges of the light-transmitting substrate 10 by an oblique vapor deposition method to form fine metal wires 20 (height Hm: 100 nm, width Dm: 40 nm).

(Process (II))
Silicon oxide was attached as a target to an in-line sputtering apparatus (manufactured by Nisshin Seiki Co., Ltd.) equipped with a load lock mechanism. The light-transmitting substrate 10 on which the fine metal wires 20 are formed is set in the sputtering apparatus, and silicon oxide is vapor-deposited from the direction perpendicular to the surface on the fine metal wire 20 side under the condition that the deposition amount is 20 nm. An inorganic oxide layer 30 (thickness Da and Ha: 20 nm) was formed.

(Process (III))
A fluorine-containing compound (manufactured by Daikin Industries, Optool DSX) having a hydrolyzable silyl group and a fluoroalkyl group (having an etheric oxygen atom between carbon-carbon atoms) is used as a fluorine-based solvent (Asahi Glass Co., Ltd., CT- Solv.100) is diluted with a solution (concentration: 0.1% by mass), and the light-transmitting substrate 10 on which the fine metal wires 20 and the inorganic oxide layer 30 are formed is dipped and pulled up, and then immediately after the fluorinated solvent. (Asahi Glass Co., Ltd., CT-Solv. 100) was used for rinsing. Placed in a constant temperature and humidity chamber at 60 ° C. and 90% RH for 1 hour, a fluorine-containing compound layer 32 (thickness Df and Hf: 2 nm) was formed on the surface of the inorganic oxide layer 30, and the wire grid polarizer 2 was Obtained.

  The obtained wire grid polarizer 2 was evaluated for scratch resistance. Moreover, the dynamic friction coefficient was measured about the smooth cured film of the same laminated structure. The results are shown in Table 1.

[Example 2]
A wire grid polarizer was obtained in the same manner as in Example 1 except that the step (II) was not performed.
The wire grid polarizer not having the inorganic oxide layer 30 was evaluated for scratch resistance. Moreover, the dynamic friction coefficient was measured about the smooth cured film of the same laminated structure. The results are shown in Table 1.

[Example 3]
A wire grid polarizer was obtained in the same manner as in Example 1 except that the steps (II) and (III) were not performed.
The wire grid polarizer not having the inorganic oxide layer 30 and the fluorine-containing compound layer 32 was evaluated for scratch resistance. Moreover, the dynamic friction coefficient was measured about the smooth cured film of the same laminated structure. The results are shown in Table 1.

As shown in Table 1, Example 3 is not coated with an inorganic oxide layer or a fluorine-containing compound layer, is not slippery, and the metal layer is exposed, so that a large light leakage ΔT even under a low load condition of 50 g × 20 times. Was observed. Further, Example 2 is covered with the fluorine-containing compound layer and is slippery and hardly scratched. However, since there is no inorganic oxide protective layer, a large light leakage occurs even under a low load condition of 50 g × 20 times. ΔT was observed.
On the other hand, Example 1 is coated with an inorganic oxide layer, a fluorine-containing compound layer, and both layers, so that light leakage ΔT is low compared to Examples 2 and 3, and very excellent scratch resistance. showed that.

  The wire grid polarizer of the present invention is useful as a polarizer for an image display device such as a liquid crystal display device, a rear projection television, or a front projector.

DESCRIPTION OF SYMBOLS 1 Wire grid type polarizer 2 Wire grid type polarizer 3 Wire grid type polarizer 10 Light transmissive substrate 20 Metal fine wire 30 Inorganic oxide layer 32 Fluorine-containing compound layer 40 Liquid crystal display device 44 Liquid crystal panel 45 Backlight unit

Claims (4)

A light transmissive substrate;
A plurality of fine metal wires arranged in parallel to each other on the light-transmitting substrate;
An inorganic oxide layer covering at least the top of the fine metal wires;
A wire grid type polarizer comprising: a fluorine-containing compound layer formed by treating at least the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to an inorganic oxide.   The wire grid type polarizer in which the inorganic oxide layer covers the two side surfaces of the fine metal wires and the top portion sandwiched between them, and the surface of the light-transmitting substrate between the fine metal wires. A method for producing a wire grid polarizer according to claim 1 or 2,
Forming a plurality of fine metal wires arranged in parallel with each other on a light-transmitting substrate;
Forming an inorganic oxide layer by vapor-depositing an inorganic oxide on the light-transmitting substrate on the side on which the fine metal wires are formed;
And a step of forming a fluorine-containing compound layer by treating at least the surface of the inorganic oxide layer with a fluorine-containing compound having a group reactive to the inorganic oxide. Method. A liquid crystal panel having a liquid crystal layer sandwiched between a pair of substrates;
A backlight unit;
A liquid crystal display device comprising: the wire grid polarizer according to claim 1.

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