JP2007057873A - Method of manufacturing grid polarization film, grid polarization film, polarizing element and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a grid polarization film, which is excellent in polarization-separating performance, has abrasion resistance and anti-fouling property and has satisfactory handling property, with an efficient, inexpensive and simple process. <P>SOLUTION: According to the manufacturing method comprising a step of producing cracking on a B layer by stretching a stacked body composed of an A layer made of resin, the B layer which is formed on the whole surface of at least one side surface of the A layer and comprises a material X having an absolute value of difference between a real number part n and an imaginary number part κ of a complex refractive index (N=n-iκ) of 1.0 or more and a C layer made of resin, the grid polarization film in which a plurality of slenderly and linearly extended b layers comprising a material X having an absolute value of difference between the real number part n and the imaginary number part κ of the complex refractive index (N=n-iκ) of 1.0 or more are arranged in parallel while being separated from each other can be obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a grid polarizing film, a grid polarizing film, a polarizing element, and a liquid crystal display device used for optical communication, optical recording, a sensor, an image display device, and the like. In particular, the present invention relates to a method for producing a grid polarizing film having excellent polarization separation performance, a grid polarizing film obtained by this production method, a polarizing element using the same, and a liquid crystal display device.

  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. When such a metal grid is formed, when the grid period is shorter than the wavelength of the incident light, the polarization component parallel to the linear metal forming the metal grid is reflected and the perpendicular polarization component is transmitted. It functions as a polarizer that creates single polarized light. 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.

  As a method for producing a grid polarizing film in which a grid polarizer is formed on a resin film substrate, 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 below the melting point of the metal film. And a grid-type polarizing optical element manufacturing method in which a metal film is cracked in a direction perpendicular to the stretching direction to form a structure composed of a metal part having an anisotropic shape and a dielectric part. Is disclosed.

  Patent Document 2 discloses a film having a higher order structure in which crystal parts and amorphous parts are alternately connected, or one side of a film having a higher order structure in which two kinds of phases having different glass transition temperatures are alternately connected in the stretching direction. Polarizing optics that forms a structure consisting of anisotropic conductive parts and polymer dielectric parts by forming a composite film by forming a conductive thin film on the entire surface of both sides, stretching the composite film, and heat fixing An element manufacturing method 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 or Patent Document 2 is such that the metal grid formed on the surface of the resin film is weak against friction, impact, and dirt. The performance easily deteriorated.
An object of the present invention is to provide a method for producing a grid polarizing film having an excellent handling property, having an excellent polarization separation performance, scratch resistance and antifouling property, in an efficient, inexpensive and simple process. There is.

  The inventor has an absolute value of the difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) formed on the A layer made of resin and at least one surface of the A layer. Including stretching a laminate having a B layer containing a material X of 0.0 or more and a C layer made of a resin formed on the B layer, thereby causing the B layer to crack. By an efficient, inexpensive and simple manufacturing method, a grid polarizing film in which a plurality of elongated and linearly extending b layers containing the material X are arranged in a state of being separated from each other is obtained. The present inventors have found that it is excellent in scratch resistance and antifouling properties, and have completed the present invention based on this finding.

Thus, according to the present invention,
(1) A layer made of resin;
A B layer formed on at least one surface of the A layer, which includes a material X having an absolute value of a difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) of 1.0 or more. When,
Forming a crack in the B layer by stretching a laminate having a C layer made of a resin formed on the B layer,
There is provided a method for producing a grid polarizing film, in which a plurality of elongated and linearly extending b layers including the material X are arranged in a state of being separated from each other.

Also according to the invention,
(2) The laminate is
On at least one surface of the resin film a constituting the A layer,
A method for producing the grid polarizing film, which is obtained by forming a B layer comprising the material X and then laminating a resin film c constituting the C layer on the B layer,
(3) The manufacturing method of the said grid polarizing film whose material X is a metal,
(4) The manufacturing method of the said grid polarizing film whose metal is aluminum,
(5) The method for producing the grid polarizing film, wherein the formation of the B layer includes vapor deposition of the material X,

(6) In stretching the laminate,
The stretching ratio R1 in the first stretching direction is 1.25 to 10 times, and the stretching ratio R2 in the second stretching direction orthogonal to the first stretching direction is 0.85 to 2 times,
And the manufacturing method of the said grid polarizing film whose draw ratio R1 is larger than draw ratio R2,
(7) The manufacturing method of the grid polarizing film in which the laminated body is long and is continuously stretched, and / or (8) the first stretching direction is substantially the same as the width direction of the long laminated body. A method of manufacturing the grid polarizing film, which is parallel, is provided.

Moreover, according to the present invention,
(9) A grid polarizing film obtained by the above production method,
(10) The space surrounded by the elongated and linearly extending b layer containing the material X, the resin A layer and the resin C layer is hollow, and the hollow is air, inert gas, organic gas Alternatively, the grid polarizing film filled with the mixture and / or (11) a grid polarizing film with an antireflection layer further including an antireflection layer on at least one surface of the grid polarizing film is provided. Is done.

According to the present invention,
(12) A polarizing element obtained by superimposing the grid polarizing film and another polarizing optical film is provided, and (13) as another preferred embodiment, the other polarizing optical film is an absorptive polarizing film, and the grid polarizing film The polarizing element in which the transmission axis of the light-absorbing polarizing film and the transmission axis of the absorbing polarizing film are substantially parallel is provided, and (14) a liquid crystal display device including the grid polarizing film or the polarizing element is provided.

  The method for producing a grid polarizing film of the present invention includes a process in which a known resin molding method, stretching method, and film forming method such as a metal film are combined under specific conditions, and therefore can be performed efficiently and simply. it can. And the grid polarizing film obtained with the manufacturing method of this invention 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.

In the present invention, the elongated and linearly extending b layers containing the material X having a difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) of 1.0 or more are separated from each other. The manufacturing method of the grid polarizing film arranged in a row
A layer made of resin;
A B layer formed on at least one surface of the A layer, which includes a material X having an absolute value of a difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) of 1.0 or more. When,
It includes causing a crack in the B layer by stretching a laminate having a C layer made of a resin formed on the B layer.

  The A layer and the C layer of the laminate used in the method for producing the grid polarizing film of the present invention are not particularly limited as long as they are made of a transparent resin. 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). The resins of the A layer and the C layer may be the same or different.

  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 layer and C layer which consist of transparent resin are obtained by shape | molding the said transparent resin by a well-known method. Examples of the molding method include a cast molding method, an extrusion molding method, and an inflation molding method.

The A layer and the C layer are usually in the form of a sheet or a film, and preferably have a smooth surface with a light transmittance in the visible region of 400 to 700 nm of 80% or more. Moreover, the average thickness of A layer and C layer is 5 micrometers-1 mm normally from a viewpoint of handleability, Preferably it is 20-200 micrometers. The thicknesses of the A layer and the C layer may be the same or different.
Also, A layer and C layer, defined values in retardation Re (Re = d × measured at that wavelength _{550nm (n x -n y),} n x, n y is the plane of the layer A or the layer C Main refractive index; d is an average thickness of the A layer or the C layer), and 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.

  The layer B of the laminate used in the method for producing a grid polarizing film of the present invention contains a material X 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. It is a waste. The B layer is formed on at least one surface of the A layer, and the C layer is laminated on the B layer. According to the manufacturing method of the present invention, by forming a crack in the B layer, it is possible to form a plurality of b layers extending in a linear shape including the material X, which are arranged apart from each other.

  The material X 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 X 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 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.

Although the details are unknown, the value of | n−κ | has the following significance. First, in the case of n <κ, it is shown that κ is larger and n is smaller. The larger κ is, the higher the conductivity and the more free electrons that can vibrate in the longitudinal direction of the b layer. Therefore, the electric field generated by the incidence of polarized light (polarized light in a direction parallel to the longitudinal direction of the b layer) is generated. It becomes stronger and the reflectance for the polarized light is increased. Since the width of the b layer is small, electrons do not move in the direction perpendicular to the longitudinal direction of the b layer, and the above effect does not occur for polarized light in the direction perpendicular to the longitudinal direction of the b layer. To do. In addition, since the wavelength in the medium of incident light is smaller when n is smaller, the size (line width, pitch, etc.) of the fine concavo-convex structure is relatively small, and is less susceptible to the effects of scattering, diffraction, Light transmittance (polarized light in a direction perpendicular to the b layer) and reflectance (polarized light in a direction parallel to the b layer) are increased.
On the other hand, in the case of n> κ, it is shown that n is larger and κ is smaller. As n increases, the difference in refractive index n between the b layer and the portion adjacent to it (air in FIG. 2) increases, and structural birefringence is more likely to occur. On the other hand, if κ is large, light absorption increases, so it is preferable that κ is small in order to prevent light loss.

  The method for forming this B 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. Of these, vacuum deposition and sputtering are preferred.

  The laminated body used for this invention is not restrict | limited especially by the manufacturing method. For example, a B layer comprising the material X is formed on at least one surface of the resin film a, and a resin film c is bonded onto the B layer, or a resin solution is applied onto the B layer. The method of drying etc. are mentioned.

In the production method of the present invention, the laminate having the A layer, the B layer, and the C layer is stretched.
FIG. 1 is a view showing an example of a laminate used in the production method of the present invention. In the laminate shown in FIG. 1, a B layer 11 containing the material X is formed on an A layer 10 made of a transparent resin film. The B layer can be easily obtained by forming a film by a method such as vapor deposition. A C layer 13 made of a transparent resin is formed on the B layer. The laminate before stretching has a length of XB and YB. This laminate is stretched in the first stretching direction 15.

In the present invention, the stretching method is not particularly limited, but the stretching ratio R1 in the first stretching direction (= length after stretching XA / length before stretching XB) is preferably 1.25 to 10 times, particularly preferably. Is 1.5 to 3.0 times, and the draw ratio R2 in the second draw direction perpendicular to the first draw direction (= length YA after drawing / length YB before drawing) is preferably 0. It is preferable that the film is stretched so that the stretching ratio R1 is larger than the stretching ratio R2 (see FIGS. 1 and 2).
As a method for performing such stretching, for example, (i) the uniaxial stretching is performed while the shrinkage rate in the direction perpendicular to the stretching direction is suppressed to 15% or less, preferably 10% or less, more preferably 5% or less. And (ii) biaxial stretching. It is efficient and preferable to perform the stretching continuously using a long laminate.

In the stretching method (i), uniaxial stretching is performed by suppressing the contraction of the length in the direction perpendicular to the stretching direction to 15% or less against the force to shrink in the direction perpendicular to the stretching direction. The b layer can be formed without causing wrinkles. More specifically, the length XA after stretching in the uniaxial stretching direction (first stretching direction) is 1.25 to 10 times, preferably 1.5 to 3.0 times the length XB before stretching. The length YA after stretching in the direction orthogonal to the uniaxial stretching direction (second stretching direction) is 0.85 to 1.05 times, preferably 0.9 to 1.05 times the length YB before stretching, More preferably, it is 0.95 to 1.05 times.
A transverse uniaxial stretching method is a typical example of a method capable of stretching at such a magnification. The horizontal uniaxial stretching method is a method of stretching a long laminate in the width direction. A tenter stretching machine can be used as an apparatus for performing the horizontal uniaxial stretching method. When lateral uniaxial stretching is performed, a crack is formed along the flow direction (MD direction) of the B layer, and a b layer that is elongated in the flow direction and extends linearly can be formed.

In the stretching method (ii), biaxial stretching is performed. In the biaxial stretching method, since the film is stretched in all the longitudinal and lateral directions, the laminate does not shrink and a b-layer without wrinkles can be formed. More specifically, the length XA after stretching in the first stretching direction is 1.25 to 10 times, preferably 1.5 to 3.0 times the length XB before stretching. The length YA after stretching in the second stretching direction orthogonal to the direction is 1 to 2 times, preferably 1.05 to 1.2 times the length YB before stretching, and is a length relative to the length XB before stretching. The laminate is stretched so that the length XA is larger than the length YA with respect to the length YB before stretching.
Biaxial stretching includes a sequential biaxial stretching method and a simultaneous biaxial stretching method, both of which are applicable. In the sequential biaxial stretching method, the longitudinal uniaxial stretching may be performed first, followed by the lateral uniaxial stretching, or the lateral uniaxial stretching may be performed first, and then the longitudinal uniaxial stretching may be performed.
In the simultaneous biaxial stretching method, a tenter simultaneous biaxial stretching machine is preferably used.

  For example, the stretching machine in FIG. 3 includes a plurality of gripping means 2 for gripping the end of the laminate 1. The gripping means 2 is attached to an endless link device 3 (not shown in the figure, a part of the link and one endless link are omitted) composed of a plurality of equal length link devices formed in a fold shape. The endless link device 3 is driven by an inlet side sprocket 4 and an outlet side sprocket 9. The endless link device 3 travels from left to right in FIG. 3 and is guided by guide rails 5, 6, 7 and 8 arranged in a divergent shape. In FIG. 3, the interval in the width direction of the gripping means 2 gradually increases as the interval between the upper and lower guide rails increases. Further, since the distance between the upper and lower guide rails 6 and 8 is narrowed, the angle of the isometric link device is widened and the distance in the flow direction of the gripping means 2 is gradually increased. Both ends of the laminate 1 are gripped by the gripping means 2 at the entrance of the stretching machine, and are stretched simultaneously in two directions in the vertical and horizontal directions by increasing the spacing of the gripping means, and removed from the gripping means 2 at the exit of the stretching machine.

  In the biaxial stretching of the long laminate, the first stretching direction may be either the length direction or the width direction, but considering the stability in production, the first stretching direction is preferably the width direction. . By making the first extending direction substantially parallel to the width direction, a crack is formed along the flow direction of the B layer, and a b layer elongated in the flow direction can be formed.

The b layers formed by the cracks in the B layer are elongated and linear, and a plurality of b layers are arranged in a state of being separated from each other. For example, as shown in FIG. 2, a plurality of b layers 311 are stacked side by side between the A layer 310 and the C layer 313. The pitch of the b layer is ½ or less of the wavelength of light used. The smaller the width and height of the b layer, the smaller the absorption of the polarization component in the transmission direction, which is preferable in terms of characteristics. In the grid polarizing film used for visible light, the pitch of the b layer is usually 50 to 1000 nm, the width of the b layer is usually 25 to 600 nm, and the height of the b layer is 10 to 800 nm. The b layer usually only needs to extend longer than the wavelength of light, and the length of the b layer is preferably 800 nm or more. The height of the b layer can be adjusted by the thickness of the B layer. The length, pitch and width of the b layer can be adjusted by the stretching speed, the stretching temperature and the like.
Note that the b layer does not necessarily have the same shape and size as shown in FIG. 2, and may be any shape that has a longer side and a shorter side than the wavelength of light and a large aspect ratio. Also, the adjacent elongated and linearly extending b layers do not have to be completely separated from each other, and any layer may be used as long as they are partially separated. For example, an elongated and linearly extending b layer may be divided into two parts in the middle, or two elongated and linearly extending b layers may be combined in the middle and become one. Good.

  In the grid polarizing film of the present invention, the space surrounded by the elongated and linearly extending b layer containing the material X, the A layer made of resin and the C layer made of resin is hollow, and the hollow is air, It is preferably filled with an active gas, an organic gas or a mixture thereof. Examples of the inert gas include nitrogen and argon. Examples of the organic gas include gasified volatile components contained in the resin of the A layer or the C layer.

  The grid polarizing film of the present invention preferably further includes an antireflection layer on at least one surface thereof. The average thickness of the antireflection layer is preferably 0.01 to 1 μm, more preferably 0.02 to 0.5 μm. The antireflection layer can be selected from known ones. For example, a low refractive index layer composed of an inorganic compound and a high refractive index layer composed of an inorganic compound are repeatedly laminated. A low refractive index layer on a high refractive index layer And the like laminated. In the present invention, it is preferable to laminate a low refractive index layer formed of a material having a micro air layer on a high refractive index layer.

  Therefore, an antireflection layer in which a low refractive index layer formed of a material having a minute air layer on a high refractive index layer is laminated will be described.

  In the present invention, when the A layer or the C layer is already a high refractive index layer, the A layer or the C layer can be used as it is as a high refractive index layer. Of course, the high refractive index layer was formed on the surface of the A layer or the C layer as a layer different from the A layer or the C layer (a layer provided separately may be referred to as a “hard coat layer”). It may be a thing. When forming on the surface of A layer or C layer, the thickness of a high refractive index layer becomes like this. Preferably it is 0.5-30 micrometers, More preferably, it is 3-15 micrometers.

  The high refractive index layer is preferably formed from a material having a hardness of “2H” or higher in a pencil hardness test (test plate is a glass plate) shown in JIS K5600-5-4. Examples of the material for the high refractive index layer include organic hard coat materials such as organic silicone, melamine, epoxy, acrylic, and urethane acrylate; and inorganic hard coat materials such as silicon dioxide. Of these, urethane acrylate-based and polyfunctional acrylate-based hard coat materials are preferably used from the viewpoint of good adhesive strength and excellent productivity.

High refractive index layer has a refractive index _{n H} is between the refractive index _{n L} of the low refractive index layer stacked thereon, _{n H} ≧ 1.53, and √n _H -0.2 _{<n L} It is preferable to have a relationship of <√n _H +0.2 in order to develop the antireflection function.

  The high refractive index layer contains various fillers for the purpose of adjusting the refractive index, improving the flexural modulus, stabilizing the volume shrinkage, improving heat resistance, antistatic properties, antiglare properties, etc., as desired. You may squeeze it. Furthermore, various additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, and an antifoaming agent can be blended.

  Fillers for adjusting the refractive index and antistatic properties of the high refractive index layer include titanium oxide, zirconium oxide, zinc oxide, tin oxide, cerium oxide, antimony pentoxide, tin-doped indium oxide (ITO), antimony And tin oxide (IZO) doped with aluminum, zinc oxide (AZO) doped with aluminum, and tin oxide (FTO) doped with fluorine. In view of maintaining transparency, antimony pentoxide, ITO, IZO, ATO, and FTO are preferred fillers. The primary particle diameter of these fillers is usually 1 nm to 100 nm, preferably 1 nm to 30 nm.

  The filler for imparting antiglare properties preferably has an average particle size of 0.5 to 10 μm, more preferably 1 to 7 μm. Specific examples of fillers that impart antiglare properties include polymethyl methacrylate resins, vinylidene fluoride resins and other fluororesins, silicone resins, epoxy resins, nylon resins, polystyrene resins, phenol resins, polyurethane resins, crosslinked acrylic resins, Filler made of organic resin such as crosslinked polystyrene resin, melamine resin, benzoguanamine resin; or inorganic such as titanium oxide, aluminum oxide, indium oxide, zinc oxide, antimony oxide, tin oxide, zirconium oxide, ITO, magnesium fluoride, silicon oxide The filler which consists of a compound is mentioned.

The low refractive index layer formed on the high refractive index layer is formed of a material having a minute air layer. The thickness of the low refractive index layer is usually 10 to 1000 nm, preferably 30 to 500 nm.
Examples of the material having a minute air layer include airgel. The airgel is a transparent porous body in which minute bubbles are dispersed in a matrix. Most of the size of the bubbles is 200 nm or less, and the content of the bubbles is usually 10 to 60% by volume, preferably 20 to 40% by volume. Aerogels include silica aerogels and porous bodies in which hollow particles are dispersed in a matrix.

  Silica aerogel is produced by hydrolysis of alkoxysilane as disclosed in U.S. Pat. No. 4,402,927, U.S. Pat. No. 4,432,956 and U.S. Pat. No. 4,610,863. The gel compound composed of the silica skeleton obtained by the polymerization reaction can be produced by wetting with a solvent (dispersion medium) such as alcohol or carbon dioxide and removing the solvent by supercritical drying. Silica airgel is manufactured in the same manner as described above using sodium silicate as a raw material as disclosed in US Pat. No. 5,137,279, US Pat. No. 5,124,364, and the like. Can do.

  In the present invention, as disclosed in JP-A-5-279011 and JP-A-7-138375, hydrolyzing the gel-like compound obtained by hydrolysis and polymerization reaction of alkoxysilane, It is preferable to impart hydrophobicity to the silica airgel. Hydrophobic silica airgel imparted with hydrophobicity is difficult for moisture, water, and the like to enter, and can prevent performance such as refractive index and light transmittance of silica airgel from deteriorating.

  Examples of the porous body in which hollow fine particles are dispersed in a matrix include porous bodies as disclosed in Japanese Patent Application Laid-Open Nos. 2001-233611, 2002/021259, and 2003-149642. Can be mentioned. The porous body in which the hollow fine particles are dispersed in the matrix is not included in the thermoplastic resin layer.

The material used for the matrix is selected from materials that meet conditions such as dispersibility of hollow fine particles, transparency of the porous body, and strength of the porous body. For example, hydrolyzable organosilicon compounds such as polyester resin, acrylic resin, urethane resin, vinyl chloride resin, epoxy resin, melamine resin, fluorine resin, silicone resin, butyral resin, phenol resin, vinyl acetate resin, alkoxysilane, Examples include decomposed products.
Among these, acrylic resin, epoxy resin, urethane resin, silicone resin, hydrolyzable organosilicon compound and hydrolyzate thereof are preferable from the viewpoint of dispersibility of the hollow fine particles and the strength of the porous body.

The hollow fine particles are not particularly limited, but inorganic hollow fine particles are preferable, and silica-based hollow fine particles are particularly preferable. Examples of the inorganic compound constituting the inorganic hollow fine particles include SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , Ce ₂ O ₃ , P ₂ O ₅ , Sb ₂ O ₃ , MoO _{3. , ZnO 2, WO 3, TiO} 2 -Al 2 O 3, TiO 2 -ZrO 2, In 2 O 3 -SnO 2, Sb 2 O 3 -SnO 2 or the like can be exemplified.

The outer shell of the hollow fine particles may be porous having pores, or may be one in which the pores are closed and the cavity is sealed against the outside of the outer shell. The outer shell may have a multilayer structure including an inner layer and an outer layer. When a fluorine-containing organic silicon compound is used for forming the outer layer, the refractive index of the hollow fine particles is lowered, the dispersibility to the matrix is improved, and the effect of imparting antifouling properties to the low refractive index layer is also produced. . Specific examples of the fluorine-containing organosilicon compound include 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, and heptadecafluoro. Examples include decyltrichlorosilane, heptadecafluorodecyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane. The thickness of the outer shell is usually 1 to 50 nm, preferably 5 to 20 nm. The thickness of the outer shell is preferably in the range of 1/50 to 1/5 of the average particle diameter of the inorganic hollow fine particles.
Moreover, the solvent used when preparing the hollow fine particles and / or the gas that enters during the drying may be present in the cavity, or a precursor substance for forming the cavity may remain in the cavity.

  The average particle size of the hollow fine particles is not particularly limited, but is preferably in the range of 5 to 2,000 nm, and more preferably 20 to 100 nm. Here, the average particle diameter is the number average particle diameter determined by observation with a transmission electron microscope.

  The grid polarizing film of the present invention may further contain an antifouling layer. The antifouling layer is a layer capable of imparting water repellency, oil repellency, sweat resistance, antifouling properties and the like to the surface of the grid polarizing film. As a material used for forming the antifouling layer, a fluorine-containing organic compound is suitable. Examples of the fluorine-containing organic compound include fluorocarbon, perfluorosilane, or a polymer compound thereof. The average thickness of the antifouling layer is preferably 1 to 50 nm, more preferably 3 to 35 nm.

  The polarizing element of the present invention is formed by superimposing the grid polarizing film and another polarizing optical film. Examples of other polarizing optical films include an absorbing polarizing film, a retardation element, and a polarizing diffraction element. In particular, when the polarizing element of the present invention is used as a brightness enhancement element of a liquid crystal display device, the other polarizing optical film is preferably an absorptive 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 polarization transmission axis of the grid polarizing film and the polarization 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 polarizing element of this invention is not specifically limited by the manufacturing method. For example, the grid polarizing film and the other polarizing optical film while simultaneously unwinding the long grid polarizing film wound in a roll shape and another long polarizing optical film wound in a roll shape from the roll. And a method including adhering to each other. An adhesive can be interposed on the adhesion surface between the grid polarizing film and the other polarizing optical film. As a method for bringing the grid polarizing film and the other polarizing optical film into close contact with each other, there is a method in which the grid polarizing film and the other polarizing optical film are pressed together and sandwiched between nips of two parallelly arranged rolls.

  The liquid crystal display device of the present invention includes the grid polarizing film or the polarizing element. 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.

  The grid polarizing film of the present invention has a property of transmitting one of linearly polarized light orthogonal to each other and reflecting the other. Further, the polarizing element of the present invention has a property of transmitting one of orthogonal linearly polarized light and reflecting the other when irradiated with light from the grid polarizing film side. In the transmissive liquid crystal display device of the present invention, the grid polarizing film and the polarizing element of the present invention (arranged so that the grid polarizing film of the polarizing element is on the backlight side) are disposed between the backlight device and the liquid crystal cell. Then, the light emitted from the backlight device is separated into two linearly polarized light by the grid polarizing film, and one linearly polarized light returns to the liquid crystal cell and the other linearly polarized light returns to 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 an image 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.

(Transparent cycloolefin polymer film)
A pellet of a transparent cycloolefin polymer (manufactured by Nippon Zeon Co., Ltd., ZEONOR 1420, glass transition temperature 136 ° C.) was dried at 100 ° C. for 4 hours using a hot air dryer in which nitrogen was circulated. The pellets were then extruded at a molten resin temperature of 260 ° C. using a T-die film melt extrusion machine equipped with a 50 mmφ screw to obtain a transparent cycloolefin polymer film having a width of 700 mm and a thickness of 80 μm. It was.

(Resin for adhesive layer)
A 9-methyl-tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] hydrogenated ring-opened polymer of dodec-3-ene (MTD) (glass transition temperature 140 ° C., hydrogenation rate about 100%, number average molecular weight about 28000) 200 parts, maleic anhydride 6. 34 parts and 470 parts of t-butylbenzene were added and heated to 135 ° C. under a nitrogen gas atmosphere to uniformly dissolve the resin. A solution in which 1.75 parts of dicumyl peroxide was dissolved in 33 parts of cyclohexane was dropped into this resin solution over 2 hours while maintaining a liquid temperature of 135 ° C. After completion of the dropwise addition, the temperature was maintained at 135 ° C. and the reaction was continued for 3 hours. The reaction solution was cooled to room temperature, and 2500 parts of toluene was added to the reaction solution to obtain a diluted resin solution. Next, the diluted resin solution was added dropwise to a mixed solution composed of 13000 parts of isopropyl alcohol and 4000 parts of acetone while vigorously stirring to solidify the resin. The coagulated resin was separated by filtration and dried at 105 ° C. for 24 hours to obtain an adhesive layer resin. The yield was 204 parts and the yield was 98%.

(Hard coat agent)
Hexafunctional urethane acrylate oligomer (trade name: NK Oligo U-6HA, Shin-Nakamura Chemical Co., Ltd.) 30 parts, butyl acrylate 40 parts, isobornyl methacrylate (trade name: NK Ester 1B, Shin-Nakamura Chemical Co., Ltd.) 30 parts, Then, 10 parts of 2,2-dimethoxy-1,2-diphenylethane-1-one was mixed with a homogenizer to prepare a hard coat agent having ultraviolet curing properties.

Example 1
(Laminated film 1)
A continuous aluminum thin film layer having a thickness of 50 nm was formed on one side of the transparent cycloolefin polymer film (length 300 m) by continuous vacuum deposition. Next, a 0.2% solution of aminopropyltriethoxysilane (ethanol: water = a solvent having a weight ratio of 4: 1) is continuously applied onto the surface of the aluminum thin film layer so that the thickness after coating is 5 μm. Then, the film was passed through a tunnel drier in which hot air having a temperature of 120 ° C. was circulated for 2 minutes, and the coating film was dried to obtain a laminated film 1.

(Laminated film 2)
200 parts of the adhesive layer resin was dissolved in 800 parts of cyclopentyl methyl ether and filtered through a filter having a pore diameter of 1 μm to obtain a resin solution having a viscosity of 130 cP. The obtained resin solution was continuously applied to one side of the transparent cycloolefin polymer film (length: 300 m), and an adhesive layer having a thickness of 3 μm was laminated to obtain a laminated film 2.

(Laminated film 3)
Next, the laminated film 2 was laminated so that the adhesive layer of the laminated film 2 and the coating film surface of the laminated film 1 were in contact with each other, and thermocompression bonded with a pressure roll placed in an atmosphere at a temperature of 100 ° C. to obtain a laminated film 3. .

(Grid Polarized Film 1)
The laminated film 3 was horizontally uniaxially stretched using a tenter stretching machine at a temperature of 150 ° C. so that the stretching ratio R1 was 2.5 times in the TD direction and the stretching ratio R2 was 1 time in the MD direction. The hard coat agent is continuously applied to one side of the stretched laminated film so that the film thickness after curing is 5 μm, and then passed through a tunnel dryer set at 80 ° C. over 5 minutes. Was dried, and the hard coat agent was cured by irradiating ultraviolet rays with an integrated light amount of 300 mJ / cm ² to obtain a grid polarizing film 1.

A light diffusing sheet and a grid polarizing film 1 (cut to a predetermined size) are sequentially placed on the exit surface side of the light guide plate in which the cold cathode tube is disposed on the incident end surface side and the light reflecting sheet is provided on the back surface side. Stacked to create a polarized light source device. Further, an absorption type polarizing plate is arranged so that its polarization transmission axis is substantially parallel to the polarization transmission axis of the grid polarizing film 1, and further, a transmission type TN liquid crystal cell and an absorption type polarizing plate are provided (polarization transmission axis). Were laminated in order so that the liquid crystal display device was perpendicular to that of the absorptive polarizing plate.
The front luminance at the time of bright display of the obtained liquid crystal display device was 242 Cd / m ^{2 as} measured by a luminance meter (trade name: BM-7, manufactured by Topcon Corporation).

Separately, steel wool # 0000 was brought into contact with the surface of the grid polarizing film 1 on which the hard coat layer was formed, and was reciprocated 20 times with a load of 0.02 MPa. No abnormalities such as scratches were visually confirmed on the surface of the grid polarizing film 1. A liquid crystal display device was prepared in the same manner as described above using the grid polarizing film 1 after being rubbed with steel wool. The front luminance was 241 Cd / m ² .

Example 2
A grid polarizing film 2 was obtained in the same manner as in Example 1 except that the stretching ratio R1 in the TD direction of the laminated film 3 was changed to 2.5 times and the stretching ratio R2 in the MD direction was changed to 1.1 times.
A liquid crystal display device was prepared in the same manner as in Example 1 except that the grid polarizing film 2 was used instead of the grid polarizing film 1. The front luminance during bright display of the obtained liquid crystal display device was 247 Cd / m ^{2 as} measured by a luminance meter. As in Example 1, the grid polarizing film 2 after rubbing with steel wool showed no abnormalities such as scratches on the surface. Further, the front luminance of the liquid crystal display device prepared using the grid polarizing film 2 after being rubbed with steel wool was 247 Cd / m ² .

Example 3
In Example 1, the grid polarizing film 3 was obtained like Example 1 except not having laminated | stacked the hard-coat layer.
A liquid crystal display device was prepared in the same manner as in Example 1 except that the grid polarizing film 3 was used instead of the grid polarizing film 1. The front luminance during bright display of the obtained liquid crystal display device was 245 Cd / m ^{2 as} measured by a luminance meter.
As in Example 1, fine scratches were observed on the entire surface of the grid polarizing film 3 after rubbing with steel wool. Moreover, the front luminance of the liquid crystal display device produced using the grid polarizing film 3 after being rubbed with steel wool was 236 Cd / m ² .

Comparative Example 1
A laminated film obtained by forming a continuous aluminum thin film layer having a thickness of 50 nm on one side of the transparent cycloolefin polymer film (length: 300 m) by continuous vacuum vapor deposition was measured using a continuous tenter stretching machine. The grid polarizing film 4 was obtained by transversely uniaxially stretching the film at a stretch ratio R1 of 2.5 times in the film width direction at 150 ° C. and a stretch ratio R2 of 1 times in the film flow direction.
A liquid crystal display device was prepared in the same manner as in Example 1 except that the grid polarizing film 4 was used instead of the grid polarizing film 1. The front luminance at the time of bright display of the obtained liquid crystal display device was 252 Cd / m ^{2 as} measured by a luminance meter.
As in Example 1, the grid polarizing film 4 after being rubbed with steel wool had fine scratches on the entire surface, and it was observed that portions where the reflectance and transmittance changed were scattered. The front luminance of the liquid crystal display device prepared using the grid polarizing film 4 after rubbing with steel wool was 218 Cd / m ² . It can be seen that the grid polarizing film 4 has insufficient scratch resistance.

Comparative Example 2
A liquid crystal display device was prepared in the same manner as in Example 1 except that the grid polarizing film 1 was not laminated. The front luminance during bright display of the obtained liquid crystal display device was 206 Cd / m ^{2 as} measured by a luminance meter.

It is a perspective view which shows an example of the laminated body used for the manufacturing method of this invention. It is a perspective view which shows an example of the grid polarizing film obtained by the manufacturing method of this invention from the laminated body shown in FIG. It is a figure which shows an example of the tenter drawing machine used for this invention.

Explanation of symbols

1: Laminated body 2: Gripping means 3: Endless link device 4: Inlet side sprocket 9: Outlet side sprocket 5, 6, 7, 8: Guide rail 10: A layer 13: C layer 11: B layer 15: First Stretching direction 310: A layer 311 after stretching: b layer 312: Hollow portion 313: C layer after stretching

Claims (14)

A layer made of resin;
A B layer formed on at least one surface of the A layer, which includes a material X having an absolute value of a difference between the real part n and the imaginary part κ of the complex refractive index (N = n−iκ) of 1.0 or more. When,
Forming a crack in the B layer by stretching a laminate having a C layer made of a resin formed on the B layer,
A method for producing a grid polarizing film, wherein a plurality of elongated and linearly extending b layers comprising the material X are arranged in a state of being separated from each other. The laminate is
On at least one surface of the resin film a constituting the A layer,
The grid polarizing film according to claim 1, which is obtained by forming a B layer comprising the material X, and then laminating a resin film c constituting the C layer on the B layer. Production method.   The manufacturing method of the grid polarizing film in any one of Claims 1-2 whose material X is a metal.   The manufacturing method of the grid polarizing film of Claim 3 whose metal is aluminum.   The manufacturing method of the grid polarizing film in any one of Claims 2-4 in which formation of B layer includes vapor-depositing material X. In stretching the laminate,
The stretching ratio R1 in the first stretching direction is 1.25 to 10 times, and the stretching ratio R2 in the second stretching direction orthogonal to the first stretching direction is 0.85 to 2 times,
And the manufacturing method of the grid polarizing film in any one of Claims 1-5 whose draw ratio R1 is larger than draw ratio R2.   The manufacturing method of the grid polarizing film in any one of Claims 1-6 in which a laminated body is a long thing and performs extending | stretching continuously.   The manufacturing method of the grid polarizing film of Claim 7 whose 1st extending | stretching direction is substantially parallel to the width direction of a elongate laminated body.   The grid polarizing film obtained by the method in any one of Claims 1-8.   The space surrounded by the thin and linearly extending b layer containing the material X, the resin A layer and the resin C layer is hollow, and the hollow is air, inert gas, organic gas, or these The grid polarizing film according to claim 9, which is filled with a mixture of The grid polarizing film with the antireflection layer which further contains an antireflection layer in the at least one surface of the grid polarizing film of Claim 9 or 10.   A polarizing element obtained by superimposing the grid polarizing film according to claim 9 and another polarizing optical film.   The polarizing element according to claim 12, wherein the other polarizing optical film is an absorptive polarizing film, and a polarization transmission axis of the grid polarizing film and a polarization transmission axis of the absorption polarizing film are substantially parallel. A liquid crystal display device comprising the grid polarizing film according to any one of claims 9 to 11 or the polarizing element according to any one of claims 12 to 13.

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