JP2008233189A - Optical composite element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical multilayer element which can display high light diffusivity without impairing luminance improvement effect, and has sufficient handling easiness even when an intermediate product during manufacture is a roll type and also has sufficient slidability to secure storage property and to provide a liquid crystal display device using the element. <P>SOLUTION: The optical composite element is constituted by uniting a reflection type polarizing element having a resin layer with cholesteric regularity and an optical anisotropic element whose front-directional retardation is nearly 1/4 time as large as a wavelength, where the resin layer with cholesteric regularity is formed by coating a base material having an alignment film layer with a composition containing a polymerizable liquid crystal compound and polymerizing it, and the base material is uneven on a surface on the opposite side from the alignment film layer. The liquid crystal display device has a light source and the optical composite element, which is equipped with a prism sheet on the light source side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  An object of the present invention is to provide an optical multilayer element that can exhibit high light diffusibility without impairing the luminance enhancement effect, and has a slip property, and a liquid crystal display device using the element.

  Conventionally, a brightness enhancement film is provided on the back side of the liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. The display luminance can be improved by increasing the amount of light transmitted through the improvement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to absorb to the polarizer.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropy. Such as a cholesteric liquid crystal polymer alignment film or a film substrate whose alignment liquid crystal layer is supported on a film substrate, reflecting either left-handed or right-handed circularly polarized light and transmitting other light Etc. have been proposed.

  Among such brightness enhancement films, a film including a reflective polarizing element having a resin layer having cholesteric regularity (optical composite element) has light diffusibility in order to improve the display quality of a liquid crystal display device. It is desirable. For this reason, proposals have been made for optical composite elements having various light-diffusing layers.

For example, Patent Document 1 describes a polarizing member in which at least a quarter-wave plate is provided on one side or both sides of a cholesteric liquid crystal layer via a light diffusion layer. As the light diffusion layer, a light diffusion sheet, In particular, those showing pressure-sensitive adhesiveness are preferred.
In Patent Document 2, a diffusion film is adhered to both sides of a polarizing layer including a reflective polarizing film.

JP 2001-154021 A JP 2001-013321 A

  In order to improve the light diffusibility without impairing the luminance enhancement effect that is the original purpose of the optical composite element, it is desirable that the layer having the light diffusivity is closer to the incident light side than the resin layer having the cholesteric regularity. . Even when a layer exhibiting light diffusibility is further arranged on the outgoing light side, the diffusibility can be kept low, which is advantageous in terms of luminance.

  In addition, the optical composite element is often an intermediate product in a roll state due to the characteristics of the manufacturing process, but the intermediate product preferably has a slip property from the viewpoint of improving handling properties and storage stability. However, it has been difficult to impart a slippery property to the resin layer having cholesteric regularity and the alignment film layer without impairing the original luminance enhancement effect.

  Furthermore, display devices such as liquid crystal display devices tend to be used in large quantities for various purposes in recent years, and it is important to reduce manufacturing costs, particularly in terms of materials used.

  Neither Patent Document 1 nor 2 considers handling of intermediate products. In Patent Document 1, a diffusing agent having pressure-sensitive adhesive properties is preferred, and there are problems such as a complicated manufacturing process. Moreover, in patent document 2, since the diffusion film was closely_contact | adhered on both sides of the polarizing layer, the brightness improvement effect was impaired.

  The object of the present invention is to exhibit high light diffusivity without impairing the brightness enhancement effect, and is sufficient to ensure sufficient handling and storage even when the intermediate product in production is rolled. An object of the present invention is to provide an optical multilayer element having slipperiness and a liquid crystal display device using the element.

The present invention provides the following [1] to [5].
[1] An optical composite element in which a reflective polarizing element including a resin layer having cholesteric regularity and an optically anisotropic element having a retardation in the front direction of approximately ¼ wavelength are integrated, The resin layer having cholesteric regularity is formed by applying and polymerizing a composition containing a polymerizable liquid crystal compound on a base material having an alignment film layer, and the base material is uneven on the side opposite to the alignment film layer. An optical composite element having a shape.
[2] The optical composite element according to [1], wherein the optically anisotropic element has a thickness direction retardation Rth of less than 0 nm.
[3] An adhesive layer is provided between the reflective polarizing element and the optically anisotropic element, and a haze value of the adhesive layer and / or the substrate is 10% to 90%, [1] or [2 ] The optical composite element of description.
[4] Obtained by coating and polymerizing the resin layer having the cholesteric regularity on the base material having the alignment film layer by winding and rolling the alignment film layer on the base material. The optical composite according to any one of [1] to [3], wherein the optical composite is manufactured by a manufacturing method including at least one of the steps of winding the resulting laminate into a roll. Device manufacturing method.
[5] A liquid crystal display device including the light source and the optical composite element according to any one of [1] to [3], and further including a prism sheet on the light source side with respect to the optical composite element. A liquid crystal display device.

  ADVANTAGE OF THE INVENTION According to this invention, the optical composite element which can exhibit a high light-diffusion property and exhibits a brightness improvement effect when it is set as a liquid crystal display device is provided. Moreover, since the optical composite element of the present invention has slipperiness, handling properties and storage stability are not impaired even when the intermediate product in the production process is rolled. Furthermore, since the high light diffusibility of the optical composite element of the present invention is exhibited mainly by the concavo-convex shape formed on the surface opposite to the alignment film layer of the substrate, it has light diffusibility as in the prior art. A sufficient effect can be obtained without providing a separate layer, which is advantageous in terms of cost.

  The optical multilayer element of the present invention is an optical composite element formed by integrating a reflective polarizing element and an optical anisotropic element, and has the following characteristics.

  The reflective polarizing element in the present invention has a resin layer having cholesteric regularity. The resin layer having cholesteric regularity is preferably a non-liquid crystalline layer. More specifically, it is preferably a resin layer in which molecular orientation having cholesteric regularity is fixed, such as a polymerized polymerizable liquid crystal compound.

  First, the polymerizable liquid crystal compound has a birefringence Δn value of 0.18 or more, preferably 0.22 or more. When a compound having an Δn value of 0.30 or more is used, the absorption edge on the long wavelength side of the ultraviolet absorption spectrum may extend to the visible range, but desired optical performance even when the absorption edge of the spectrum extends to the visible range. It can be used as long as it does not adversely affect By having such a high Δn value, a reflective polarizer having high optical performance (for example, circularly polarized light separation characteristics) can be provided.

  In the present invention, the polymerizable liquid crystal compound has one or at least two or more reactive groups in one molecule. Specific examples of the reactive group include an epoxy group, a thioepoxy group, an oxetane group, a thietanyl group, an aziridinyl group, a pyrrole group, a fumarate group, a cinnamoyl group, an isocyanate group, an isothiocyanate group, an amino group, a hydroxyl group, and a carboxyl group. , Alkoxysilyl groups, mercapto groups, vinyl groups, allyl groups, methacryl groups, and acrylic groups. By having these reactive groups, a stable cured product can be obtained when the composition constituting the resin layer having cholesteric regularity is cured. In addition, when a compound having two or more reactive groups in one molecule is used, when the composition constituting the resin layer having cholesteric regularity is cured, a highly practical and preferable film strength is obtained by crosslinking. It is done. The preferable film strength here is a pencil hardness (JIS K5400) of B or more, preferably H or more. If the film strength is lower than B, scratches are likely to occur and handling properties are lacking, which is not preferable. The upper limit of preferable pencil hardness is not particularly limited as long as it does not adversely affect the optical performance and durability test.

Examples of the polymerizable liquid crystal compound as described above include a compound represented by (Formula 1).
^{R 3 -C 3 -D 3 -C 5} -M-C 6 -D 4 -C 4 -R 4 ( Equation 1)
(Wherein R ³ and R ⁴ are reactive groups, each independently (meth) acryl group, (thio) epoxy group, oxetane group, thietanyl group, aziridinyl group, pyrrole group, vinyl group, allyl group, D ³ and D ⁴ are groups selected from the group consisting of fumarate group, cinnamoyl group, oxazoline group, mercapto group, iso (thio) cyanate group, amino group, hydroxyl group, carboxyl group, and alkoxysilyl group. A group selected from the group consisting of a bond, a linear or branched alkyl group having 1 to 20 carbon atoms, and a linear or branched alkylene oxide group having 1 to 20 carbon atoms; C ^{3 to} C ⁶ are a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —C═. N—N═C—, —NHCO— _{, -OCOO -, - CH 2 COO-} , and .M represents a group selected from the group consisting of -CH ₂ OCO- represents a mesogenic group, specifically, unsubstituted or halogen atom, a hydroxyl group, a carboxyl Group, cyano group, amino group, linear or branched alkyl group having 1 to 10 carbon atoms, one or more substituted with a halogenated alkyl group, azomethines, azoxys, biphenyls, Terphenyls, naphthalenes, anthracenes, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxane , Tolanes, alkenyl cyclohexyl benzonitrile 2-4 backbone selected from the group of classes, -O -, - S -, - S-S -, - CO -, - CS -, - OCO -, - CH 2 -, - OCH 2 - , -C = N-N = C -, - NHCO -, - OCOO -, - CH 2 COO-, and is formed are joined by a linking group of -CH ₂ OCO-, etc.).
In the present invention, the polymerizable liquid crystal compound preferably has an asymmetric structure. Here, the asymmetric structure is a structure in which R ³ -C ³ -D ³ -C ⁵ -and -C ⁶ -D ⁴ -C ⁴ -R ⁴ are different in the general formula (1) with the mesogenic group M as the center. Say. By using a polymerizable liquid crystalline compound having an asymmetric structure, alignment uniformity can be further improved.

  A method for polymerizing the polymerizable liquid crystal compound to form a resin layer having cholesteric regularity is not particularly limited. For example, a composition containing the polymerizable liquid crystal compound is applied on a substrate and polymerized. Can take the way. Also, if necessary, a plurality of resin layers may be provided by repeating the coating-polymerization process a plurality of times to form a plurality of resin layers, or by laminating a plurality of laminates having a resin layer and a supporting substrate. Good. By providing a plurality of resin layers having different reflection bands, a reflective polarizing element having a wider reflection band can be obtained.

In addition to the polymerizable liquid crystal compound, the composition containing the polymerizable liquid crystal compound may optionally contain a crosslinking agent in order to improve the film strength and durability after curing. As the cross-linking agent, it reacts simultaneously when the liquid crystal layer coated with the liquid crystal composition is cured, or heat treatment is performed after curing to accelerate the reaction, or the reaction proceeds spontaneously by moisture to increase the cross-linking density of the liquid crystal layer. Those that can be enhanced and that do not deteriorate the alignment uniformity can be appropriately selected and used, and those that are cured by ultraviolet rays, heat, moisture, etc. can be suitably used. Specific examples of the crosslinking agent include, for example, polyfunctional acrylate compounds such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate; glycidyl (meth) acrylate, ethylene glycol di Epoxy compounds such as glycidyl ether and glycerin triglycidyl ether; aziridine compounds such as 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate] and 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane; Isocyanurate type isocyanate, biuret type isocyanate, adduct type isocyanate and other isocyanate compounds; polyoxazoline compound having an oxazoline group in the side chain; Trimethoxysilane, N- (2- aminoethyl) 3-aminopropyltrimethoxysilane, alkoxysilane compounds such as 3-aminopropyltrimethoxysilane; and the like. Moreover, a well-known catalyst can be used according to the reactivity of this crosslinking agent, and productivity can be improved in addition to an improvement in film strength and durability.
The blending ratio of the crosslinking agent is preferably 0.1 to 15% by weight in a cured film obtained by curing the composition containing the polymerizable liquid crystal compound. When the blending ratio of the crosslinking agent is less than 0.1% by weight, the effect of improving the crosslinking density cannot be obtained. Conversely, when the blending ratio is more than 15% by weight, the stability of the liquid crystal layer is lowered, which is not preferable.

  As a composition containing the said polymeric liquid crystal compound, in addition to the said polymeric liquid crystal compound, a photoinitiator can be contained. As the photopolymerization initiator, known compounds that generate radicals or acids by ultraviolet rays or visible rays can be used. Specifically, 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine , 2- (4-ethoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, etc .; halomethylated triazine derivatives; halomethylated oxadiazole derivatives; 2- (2′-chlorophenyl) -4,5 -Imidazole derivatives such as diphenylimidazole dimer, 2- (2'-chlorophenyl) -4,5-bis (3'-methoxyphenyl) imidazole dimer; benzoin methyl ether, benzoin phenyl ether, benzoin isobutyl ether, benzoin Benzoin alkyl ethers such as isopropyl ether; Torakinon, 2-ethylanthraquinone, anthraquinone derivatives such as 2-t-butyl-anthraquinone; benzanthrone derivatives; benzophenone, Michler's ketone, benzophenone derivatives such as 2-methylbenzophenone;

Acetophenone derivatives such as 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone; thioxanthone, 2-ethylthioxanthone, 2- Thioxanthone derivatives such as isopropylthioxanthone; Benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate and ethyl p-diethylaminobenzoate; Acridine derivatives such as 9-phenylacridine and 9- (p-methoxyphenyl) acridine; -Phenazine derivatives such as dimethylbenzphenazine;
Di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluoropheny Examples thereof include titanocene derivatives such as -1-yl; oxime derivatives such as oxime ester compounds described in JP-A No. 2001-233842, and carbazole oxime compounds described in JP-A No. 2004-359639.
In addition, two or more compounds can be mixed depending on the desired physical properties, and if necessary, a known photosensitizer or a tertiary amine compound as a polymerization accelerator is added to control curability. You can also.

  The blending ratio of the photopolymerization initiator is preferably 0.03 to 7% by weight in the composition containing the polymerizable liquid crystal compound. If the amount of the photopolymerization initiator is less than 0.03% by weight, the degree of polymerization is lowered, and the film strength may be lowered. On the other hand, if it is more than 7% by weight, the alignment of the liquid crystal is inhibited and the liquid crystal phase may become unstable.

  The composition containing the polymerizable liquid crystal compound may contain a surfactant in addition to the polymerizable liquid crystal compound. As the surfactant, those not inhibiting the orientation can be appropriately selected and used. Specifically, as the surfactant, a nonionic surfactant containing a siloxane or a fluorinated alkyl group in the hydrophobic group portion can be preferably used, and an oligomer having two or more hydrophobic group portions in one molecule. Is particularly preferred. These surfactants are OMNOVA PolyFox PF-151N, PF-636, PF-6320, PF-656, PF-6520, PF-3320, PF-651, PF-652, Neos's Fantgent FTX- 209F, FTX-208G, FTX-204D, Seimi Chemical's Surflon KH-40, or the like can be used. The blending ratio of the surfactant is preferably 0.05% by weight to 3% by weight in a cured film obtained by curing the cholesteric liquid crystal composition. If the blending ratio of the surfactant is less than 0.05% by weight, the orientation regulating force at the air interface is lowered and an orientation defect may occur, which is not preferable. On the other hand, when it is more than 3% by weight, it is not preferable because an excessive surfactant may enter between liquid crystal molecules and lower the alignment uniformity.

  As a composition containing the said polymeric liquid crystal compound, another arbitrary component can be further contained as needed. Examples of the other optional components include a chiral agent, a solvent, a polymerization inhibitor for improving pot life, an antioxidant for improving durability, an ultraviolet absorber, and a light stabilizer. These optional components can be added as long as the desired optical performance is not deteriorated.

The substrate is not particularly limited, and a transparent resin substrate, for example, a substrate having a thickness of 1 mm and a total light transmittance of 80% or more can be used. Specifically, alicyclic olefin polymers, chain olefin polymers such as polyethylene and polypropylene, triacetyl cellulose, polyvinyl alcohol, polyimide, polyarylate, polyester, polycarbonate, polysulfone, polyethersulfone, modified acrylic polymer, epoxy resin, Examples thereof include a single layer or laminated film made of a synthetic resin such as polystyrene or acrylic resin. Among these, an alicyclic olefin polymer or a chain olefin polymer is preferable, and an alicyclic olefin polymer is particularly preferable from the viewpoint of transparency, low hygroscopicity, dimensional stability, lightness, and the like. In the case of a laminated film, a laminated film of polystyrene and acrylic resin is preferable.
The thickness of the supporting substrate is usually 20 to 300 μm, preferably 20 to 200 μm, more preferably 30 to 100 μm.

The support substrate has an alignment film layer. By having an alignment film layer, the composition containing the polymerizable liquid crystal compound applied thereon can be aligned in a desired direction. The alignment film layer is subjected to a corona discharge treatment or the like on the substrate surface as necessary, and then cellulose, silane coupling agent, polyimide, polyamide, modified polyamide, polyvinyl alcohol, epoxy acrylate, silanol oligomer, polyacrylonitrile, Dissolve polymers such as phenol resin, polyoxazole, and cyclized polyisoprene in water or solvent, and if the polymer is a modified polyamide, add a cross-linking agent, reverse gravure coating, direct gravure coating, die coating, It can be formed by applying and drying using a known method such as bar coating and then subjecting the dried coating film to a rubbing treatment. As the polymer, polyvinyl alcohol and modified polyamide are preferable, and modified polyamide is particularly preferable. The modified polyamide is obtained by modifying at least a part of the structure of a polyamide such as an aromatic polyamide or an aliphatic polyamide. Examples of the modified polyamide preferred in the present invention include at least the end groups of the aliphatic polyamide. Examples thereof include those partially amino-modified, carboxyl-modified, and hydroxyl-modified.
The thickness of the alignment film layer may be a film thickness that provides the desired alignment uniformity of the liquid crystal layer, and is preferably 0.001 to 5 μm, and more preferably 0.01 to 2 μm.

  Application | coating of the composition containing the said polymeric liquid crystal compound to the base material which has the said alignment film layer can be performed by well-known methods, such as reverse gravure coating, direct gravure coating, die coating, and bar coating. The thickness of the coating layer of the liquid crystal composition can be appropriately adjusted so that a desired liquid crystal layer dry film thickness described later can be obtained.

  Before applying the composition containing the polymerizable liquid crystal compound onto a substrate and polymerizing it, an alignment treatment can be applied as necessary. The alignment treatment can be performed, for example, by heating the coating layer at 50 to 150 ° C. for 0.5 to 10 minutes. By performing the alignment treatment, the resin layer having cholesteric regularity can be aligned well.

  After forming a coating film on the substrate, a resin layer having cholesteric regularity is polymerized to form a resin layer having cholesteric regularity. Curing of the coating proceeds by polymerizing a polymerizable composition exhibiting liquid crystallinity, and the curing step can be performed by one or more heating and / or light irradiation. Curing can be preferably performed by the following steps.

First, after performing the drying process (for example, 50-150 degreeC) which heats the coating film of the polymeric composition which shows the said liquid crystalline as needed, this coating film is 0-30 degreeC under the temperature of 0-30 degreeC. Irradiation with selective ultraviolet rays having an illuminance of 1 mW / cm ² or more and less than 10 mW / cm ² for 0.1 to 10 seconds (selective ultraviolet irradiation step). The illuminance is measured using an illuminometer having a peak sensitivity at the wavelength of the selected ultraviolet ray (specifically, for example, having a peak sensitivity at 360 nm) on the substrate surface.

  In the present invention, selective ultraviolet light (also referred to as broadband ultraviolet light) means that the degree of cross-linking of liquid crystal in the coating film of the polymerizable composition exhibiting liquid crystal properties described above varies in the depth direction of the film. It means ultraviolet light with selectively controlled possible wavelength range or irradiation intensity.

In the present invention, it is preferable to use an ultraviolet ray having a wavelength range within 100 nm as the ultraviolet ray used in the selective ultraviolet ray irradiation step. Specifically, an ultraviolet ray having a maximum irradiation intensity at a wavelength of 300 nm or more and less than 400 nm is preferable. As the light source, for example, a mercury lamp light source, a metal halide lamp light source, or the like can be used. In this way, the width of the wavelength range is controlled within 100 nm by using an ultraviolet ray with an illuminance of 0.1 mW / cm ² or more and less than 10 mW / cm ² and / or using a bandpass filter, etc., and the irradiation time is 0.1 to 10 seconds. It is preferable to use in the selective ultraviolet irradiation step under irradiation conditions.

  In addition, the control of the wavelength range specifically includes, for example, a method using a bandpass filter having a center wavelength of 365 nm, a wavelength range width centered on a wavelength at which the polymerization initiator contained in the coating film exhibits maximum absorption. And the like, and the like. The selective ultraviolet rays may be irradiated from the coating film side, from the substrate side, or from both sides of the coating film side and the substrate side, but the polymerization inhibition by oxygen is reduced. Therefore, it is preferable to irradiate from the substrate side. In addition, when irradiating from the coating film side, it is necessary to control the illuminance / irradiation time stability more severely (specifically, ± 3% or less). Is preferred.

  In this invention, it is preferable to have the process of cooling the coating film of the polymeric composition which shows the liquid crystallinity on a base material before the said selective ultraviolet irradiation process. By irradiating the coating film of the polymerizable composition exhibiting liquid crystallinity maintained at 20 ° C. to 30 ° C. with the above-described selective ultraviolet rays, a light intensity distribution is generated in the depth direction of the coating film. Cholesteric liquid crystal layers having different degrees of crosslinking in the depth direction can be formed. Examples of the cooling method include cooling with cold air supply, cooling with a cooling roll, and the like.

Next, the period of the cholesteric regularity of the coating film is changed (cholesteric regularity adjusting step).
Changing the period of the cholesteric regularity of the coating film means changing the pitch of the resin layer having the cholesteric regularity in the depth direction.

  As a method of changing the period of cholesteric regularity, (I) a step of performing a heat treatment at a temperature higher than or equal to a temperature showing a liquid crystal phase, (II) a step of further applying a liquid crystal compound to the coating film, (III) Furthermore, the process etc. which apply | coat a non-liquid crystal compound can be mentioned. In this step, one type may be used, a repeated operation thereof, or a combination of two or more types of steps may be used. Among these, it is preferable to perform the heat treatment at a temperature equal to or higher than the temperature of the liquid crystal phase (I) from the viewpoint of simple operation and effect.

  As for the heat treatment conditions, considering productivity as well as the effect of broadening the band, it is usually about 0.001 to 20 minutes at a temperature of 50 to 115 ° C., preferably 0.001 to 10 minutes at a temperature of 65 to 115 ° C. Preferably, it is 0.01 to 5 minutes at a temperature of 65 to 115 ° C. However, the temperature range in which the liquid crystal phase is developed varies depending on the type of liquid crystalline compound that forms the coating film of the polymerizable composition exhibiting liquid crystallinity, and accordingly, the processing temperature and processing time also vary.

  In the present invention, it is preferable to repeat the selective ultraviolet irradiation step (1) and the cholesteric regularity adjustment step (2) a plurality of times. By repeating a plurality of times, it is possible to change the pitch of the resin layer having cholesteric regularity more greatly. The conditions of ultraviolet irradiation and regularity adjustment are appropriately adjusted for each number of times in order to adjust the reflection band. The number of repetitions is not limited, but is preferably 2 from the viewpoint of productivity and equipment. Further, in the method of irradiating for a long time at one time, the degree of polymerization increases and the molecules do not move easily, so that the pitch of the resin layer having cholesteric regularity is hardly changed.

In the present invention, it is preferable to subsequently cure the coating film (coating film curing step).
The curing method is not particularly limited as long as the coating film is cured to have cholesteric regularity, but it is preferable to irradiate the main curing ultraviolet ray so that the integrated light amount becomes 10 mJ / cm ² or more. Here, the main curing ultraviolet ray means an ultraviolet ray set to a wavelength range or illuminance that can completely cure the coating film.

Integrated light quantity of the curing ultraviolet ray is preferably 10~1000mJ / cm ^2, more preferably is selected in the range of 50 to 800 mJ / cm ^2. The integrated light quantity is selected by measuring on the substrate surface using an ultraviolet light quantity meter or measuring the illuminance using an illuminometer and calculating the integrated light quantity = illuminance × time. The irradiation direction may be from either the coating film side or the base material side, but it is preferable to irradiate from the coating film side from the viewpoint of good irradiation efficiency of ultraviolet rays.

  Moreover, in this invention, it is preferable to perform the said main curing ultraviolet irradiation in nitrogen atmosphere. By performing the reaction under a nitrogen atmosphere, it is possible to reduce the influence of polymerization inhibition by oxygen. The oxygen concentration at the time of irradiation with the main curing ultraviolet ray is preferably 3% or less, more preferably 1% or less, and particularly preferably 500 ppm or less.

  In this invention, it is preferable to have the process of cooling the coating film of the polymeric composition which shows the liquid crystallinity on a base material before the said coating-film hardening process. The state of the pitch of the resin layer having the cholesteric regularity after the cholesteric regularity adjusting step is irradiated by irradiating the above-mentioned ultraviolet rays to the coating film of the polymerizable composition exhibiting liquid crystallinity maintained at 20 ° C. to 30 ° C. Can be maintained.

  By this coating film curing step, the mechanical properties of the resin layer having cholesteric regularity can be improved while maintaining the wide band.

  In the reflective polarizing element of the present invention, the thickness (dry film thickness) of the resin layer (liquid crystal layer) having cholesteric regularity is usually 3.0 to 9.0 μm, preferably 3.0 μm to 7.0 μm. Preferably it can be set to 3.5-6.5 micrometers. If the dry film thickness of the liquid crystal layer is thinner than 3.0 μm, the reflectivity is lowered. Conversely, if the liquid crystal layer is thicker than 9.0 μm, the liquid crystal layer is colored when observed from an oblique direction. Absent.

In the present invention, the base material has a concavo-convex shape on the side opposite to the alignment film layer. Thereby, light diffusibility is fully exhibited. That is, when the optical composite element of the present invention is used as a liquid crystal display device, the position of the base material is usually located on the light source side, that is, on the incident light side with respect to the resin layer having cholesteric regularity. On the other hand, if the uneven shape is provided on the alignment film surface of the substrate, the alignment of the liquid crystal is impaired, and the alignment film whose refractive index is closer to the substrate than air is in contact with the uneven shape. Light diffusivity cannot be obtained. Therefore, light diffusivity is exhibited without impairing the brightness enhancement effect by positioning the uneven shape on the substrate, particularly on the side opposite to the alignment film layer.
Furthermore, slipperiness is exhibited by providing an uneven shape. That is, even when an intermediate product in a manufacturing process, for example, an intermediate product in a state where an alignment film is formed on a base material, or an intermediate product in a state where a resin layer having cholesteric regularity is further formed thereon is formed into a roll shape Blocking is prevented, and handling properties and storage properties are improved.

Examples of the uneven shape include a dot pattern shape and a line pattern shape.
The size of the uneven shape is 0.5 to 500 μm in diameter when the shape is a dot pattern, preferably 1 to 50 μm in diameter, and 0.5 to 500 μm in width when the shape is a line pattern, preferably 1 to 50 μm. The dot pattern shape and line pattern shape may be regular or irregular.
Examples of the method for forming the concavo-convex shape include a method of embossing the surface to be formed, a method of applying a liquid containing fine particles to the surface to be formed and drying. The particle diameter of the fine particles is preferably 0.5 μm to 100 μm, and more preferably 1 μm to 50 μm.

  In the optical composite element of the present invention, the surface of the base material having a concavo-convex shape preferably has a slip property with respect to the surface having an alignment film layer, and particularly preferably a slip property with respect to a resin surface having a cholesteric regularity. It is what has. Thereby, the handling property of the optical composite element of the present invention is improved.

  In the present invention, the optically anisotropic element has a retardation Re (hereinafter sometimes abbreviated as “Re”) in the front direction of approximately ¼ wavelength of transmitted light. Here, the wavelength range of the transmitted light can be a desired range required for the brightness enhancement film which is a suitable application of the optical composite element of the present invention, and specifically, for example, 400 nm to 700 nm. Further, the retardation Re in the front direction is approximately ¼ wavelength of transmitted light, and the Re value is ± 65 nm from the ¼ value of the center value in the center value of the wavelength range of transmitted light, preferably It means ± 30 nm, more preferably ± 10 nm.

The optically anisotropic element desirably has a thickness direction retardation Rth (hereinafter sometimes abbreviated as “Rth”) of less than 0 nm. The value of retardation Rth in the thickness direction is preferably −30 nm to −1000 nm, more preferably −50 nm to −300 nm, in the central value of the wavelength range of transmitted light. By adopting such an optically anisotropic element having an Re value and Rth, it is possible to reduce color unevenness of emitted light while improving brightness and reducing brightness unevenness.
Here, the retardation Re in the front direction is represented by the formula I: Re = (nx−ny) × d (where nx is a direction perpendicular to the thickness direction (front direction) and gives the maximum refractive index). Ny represents a refractive index in a direction perpendicular to the thickness direction (in-plane direction) and perpendicular to nx, and d represents a film thickness). The direction retardation Rth is expressed by the formula II: Rth = {(nx + ny) / 2−nz} × d (where nx is a direction perpendicular to the thickness direction (in-plane direction) and gives the maximum refractive index) Ny is the refractive index in the direction perpendicular to the thickness direction (in-plane direction) and orthogonal to nx, nz is the refractive index in the thickness direction, and d is the film thickness. ).
In addition, the retardation Re in the front direction and the retardation Rth in the thickness direction are measured using a commercially available phase difference measuring apparatus, and the optically anisotropic elements are spaced 100 mm apart in the longitudinal direction and the width direction (longitudinal or lateral length). If the distance is less than 200 mm, three points are specified at equal intervals in that direction), and measurement is performed in a lattice point shape over the entire surface, and the average value is obtained.

  Although the material which comprises the said optically anisotropic element is not specifically limited, What has the layer which consists of a styrene resin can be used preferably. Here, the styrene-based resin is a polymer resin having a styrene structure as a part or all of the repeating unit, and polystyrene, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene. , Styrene monomers such as p-nitrostyrene, p-aminostyrene, p-carboxystyrene, p-phenylstyrene, ethylene, propylene, butadiene, isoprene, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, acrylic acid Examples thereof include copolymers with other monomers such as methyl, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylic acid, methacrylic acid, maleic anhydride, and vinyl acetate. Among these, polystyrene or a copolymer of styrene and maleic anhydride can be suitably used.

  The molecular weight of the styrenic resin used for the optically anisotropic element is appropriately selected according to the purpose of use, but is the weight average molecular weight (Mw) of polyisoprene measured by gel permeation chromatography using cyclohexane as a solvent. Usually, 10,000 to 300,000, preferably 15,000 to 250,000, and more preferably 20,000 to 200,000.

  The optically anisotropic element preferably has a laminated structure of a layer made of the styrenic resin and a layer containing another thermoplastic resin. By having the laminated structure, it is possible to provide an element that has both the optical characteristics of the styrene resin and the mechanical strength of other thermoplastic resins. Other thermoplastic resins include alicyclic olefin polymers, methacrylic resins, polycarbonates, acrylic ester-vinyl aromatic compound copolymer resins, methacrylic ester-vinyl aromatic compound copolymer resins, polyethersulfone, etc. Can be mentioned. Among these, a resin having an alicyclic structure or a methacrylic resin can be preferably used.

  The alicyclic olefin polymer is an amorphous olefin polymer having a cycloalkane structure or a cycloalkene structure in the main chain and / or side chain. Specifically, (1) norbornene polymer, (2) monocyclic olefin polymer, (3) cyclic conjugated diene polymer, (4) vinyl alicyclic hydrocarbon polymer, and these A hydride etc. are mentioned. Among these, norbornene-based polymers are more preferable from the viewpoints of transparency and moldability. Examples of the resin having these alicyclic structures include those described in JP-A No. 05-310845, JP-A No. 05-097978, and US Pat. No. 6,511,756.

  Specific examples of the norbornene-based polymer include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, hydrides thereof, and norbornene-based monomers. And addition copolymers with other monomers copolymerizable with norbornene monomers.

  The methacrylic resin is a polymer having a methacrylic acid ester as a main component, and includes a methacrylic acid ester homopolymer and a copolymer of a methacrylic acid ester and other monomers. Usually, alkyl methacrylate is used. In the case of a copolymer, acrylic acid esters, aromatic vinyl compounds, vinylcyan compounds, etc. are used as other monomers copolymerized with methacrylic acid esters.

  As a preferred specific embodiment of the optically anisotropic element used in the present invention, a multilayer film formed by laminating a film (b layer) made of another thermoplastic resin on both surfaces of a film (a layer) made of polystyrene resin. A stretched multilayer film formed by stretching can be mentioned. Hereinafter, this specific embodiment will be described.

  As the polystyrene resin constituting the a layer, the same “styrene resin” as described above can be used.

  The polystyrene resin constituting the a layer preferably has a glass transition temperature of 120 ° C. or higher, more preferably 120 to 200 ° C., and still more preferably 120 to 140 ° C.

  In the present invention, the polystyrene resin and the other thermoplastic resin have Tg (a)> Tg (b) when their glass transition temperatures are Tg (a) (° C.) and Tg (b) (° C.), respectively. ) It is preferable to satisfy the relationship of + 20 ° C. By satisfying such a relationship, optical anisotropy can be effectively given to the a layer made of polystyrene resin when stretched, and a good optical anisotropic element can be obtained.

  The method of laminating the polystyrene resin that is the material of the a layer and the other thermoplastic resin that is the material of the b layer to form a multilayer film is not particularly limited, but is a coextrusion T-die method, coextrusion inflation Known methods such as a method of forming by coextrusion such as a method, a coextrusion lamination method, a film lamination forming method such as dry lamination, and a coating forming method may be appropriately used. Among these, a molding method by coextrusion is preferable from the viewpoints of production efficiency and that volatile components such as a solvent do not remain in the film. The extrusion temperature can be appropriately selected according to the type of the polystyrene resin used and the other thermoplastic resin.

  The multilayer film is formed by laminating the b layer on both surfaces of the a layer. An adhesive layer or a pressure-sensitive adhesive layer can be provided between the a layer and the b layer, but the a layer and the b layer are directly laminated (that is, lamination of a three-layer configuration of b layer / a layer / b layer). Body). In the multilayer film, the thickness of the a layer and the b layer laminated on both sides thereof is not particularly limited, but preferably 10 to 300 μm and 10 to 400 μm, respectively.

The stretched multilayer film is formed by stretching the multilayer film. The stretched multilayer film may include an A layer provided by stretching the a layer and a B layer provided by stretching the b layer. The stretched multilayer film is a stretched film having a three-layer structure of B layer / A layer / B layer formed by stretching a laminate of b layer / a layer / b layer of the multilayer film. It is preferable.
The stretching can be preferably performed by uniaxial stretching or oblique stretching, and more preferably by uniaxial stretching or oblique stretching by a tenter.

  The front direction retardation Re and the thickness direction retardation Rth of the optically anisotropic element can be produced by appropriately adjusting stretching conditions such as a stretching temperature and a stretching ratio. The stretching temperature is preferably Tg (a) -10 ° C to Tg (a) + 20 ° C, and more preferably in the range of Tg (a) -5 ° C to Tg (a) + 15 ° C. The draw ratio is preferably 1.05 to 30 times, and more preferably 1.1 to 10 times. If the stretching temperature and the stretching ratio are out of the above ranges, the orientation may be insufficient and the refractive index anisotropy and thus the retardation may be insufficiently developed, or the laminate may be broken.

  The thickness of the optically anisotropic element is preferably 50 to 1000 μm, more preferably 50 to 600 μm.

  In the optical composite element of the present invention, the reflective polarizing element and the optical anisotropic element are integrated. For example, an adhesive layer or an adhesive layer can be provided between the reflective polarizing element and the optically anisotropic element, but they can also be laminated directly. Among these, it is preferable to provide an adhesive layer or an adhesive layer, and it is particularly preferable to provide an adhesive layer. In the present invention, the adhesive means an adhesive substance that does not exhibit tackiness at room temperature (20 ± 15 ° C .: JIS standard), and the adhesive means an adhesive substance that exhibits tackiness at room temperature. . In the present invention, “not showing tackiness” means showing tackiness of less than 2 in the ball number as measured by tilting ball tack measurement of JIS Z0237.

  The adhesive layer used in the optical composite element of the present invention preferably has light diffusibility, and in particular, a layer composed of a composition having a shear storage modulus of 1 to 500 MPa at a temperature of 23 ° C. is preferable.

  The said composition contains the main polymer which comprises an adhesive agent at least. Examples of the main polymer include acrylic polymers and acrylic copolymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, polyvinyl alcohols, ethylene / vinyl acetate copolymers, ethylene / acrylic ester copolymers, Examples include ethylene / vinyl chloride copolymer, thermoplastic elastomer, epoxy, natural rubber, and synthetic rubber. Among these, a thermoplastic elastomer, an ethylene / vinyl acetate copolymer, and an ethylene / acrylic acid ester copolymer are preferable because they are excellent in transparency, exhibit appropriate wettability and cohesion, and have excellent weather resistance. Thermoplastic elastomer is a resin having rubber elasticity at room temperature without vulcanization treatment. Specifically, styrene-butadiene block copolymer, styrene-ethylene block copolymer, styrene-butadiene- Styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylenebutylene-styrene block copolymer, styrene-ethylenepropylene-styrene block copolymer, ethylene-propylene copolymer and ethylene-propylene terpolymer , Polyethylene, polypropylene, and those having a carboxyl group or a sulfonyl group introduced thereto. The molecular weight of these main polymers is the weight average molecular weight (Mw) of polyisoprene measured by gel permeation chromatography, and is usually 10,000 to 500,000, preferably 20,000 to 400, 000.

  Depending on the type of the main polymer, other compounding agents can be blended in the composition. Examples of other compounding agents include tackifiers, crosslinking agents or curing agents, antioxidants, light diffusing agents, antifoaming agents, and stabilizers.

  The tackifier imparts adhesive force to the main polymer that is soft and has a solid surface that is easily wetted. Such tackifiers include rosin and rosin derivatives, polyterpene resins, terpene phenol resins, coumarone-indene resins, petroleum resins, hydrogenated petroleum resins and the like. Among these, petroleum resins, hydrogenated petroleum resins, and terpene phenol resins are preferable because they are excellent in transparency and compatibility with the main polymer. The compounding amount of the tackifier is preferably 2 to 50 parts by weight, more preferably 5 to 20 parts by weight with respect to 100 parts by weight of the main polymer. When the addition amount of the tackifier is less than 2 parts by weight, the effect of the tackifier is not expressed, and conversely, when the addition amount exceeds 50 parts by weight, the adhesive force decreases due to the decrease in the cohesive force of the adhesive. Tend to be.

  Examples of the crosslinking agent or curing agent include polyfunctional isocyanate crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, trimethylolpropane tolylene diisocyanate, diphenylmethane triisocyanate; ethylene glycol glycidyl ether, polyethylene glycol di Epoxy crosslinking agents or curing agents such as glycidyl ether, diglycidyl ether, trimethylolpropane triglycidyl ether; vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3 , 4-Epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) A silane crosslinking agent or curing agent such as 3-aminopropyltrimethoxysilane; a melamine resin crosslinking agent; a metal chelate crosslinking agent; an amine crosslinking agent is used. The blending amount of the crosslinking agent or curing agent is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 3 parts by weight with respect to 100 parts by weight of the main polymer. When the addition amount of the crosslinking agent or curing agent is less than 0.001 part by weight, the effect of the crosslinking agent is not exhibited, and foaming and peeling are conspicuous in a weather resistance test or the like. On the contrary, when the addition amount of the crosslinking agent or the curing agent is more than 10 parts by weight, the stress relaxation property of the adhesive is lowered, and warpage becomes conspicuous.

  Examples of the antioxidant include phenol-based antioxidants such as tetrakis (methylene-3- (3,5di-t-butyl-4-hydroxyphenyl) propionate) methane, phosphorus-based antioxidants, and thioether-based antioxidants. Is mentioned. The blending amount of the antioxidant is within a range in which the transparency and adhesive strength of the adhesive layer are not lowered.

The shear storage modulus of the composition constituting the adhesive layer used in the present invention varies depending on the main polymer composition, the addition amount of the tackifier, the addition amount of the crosslinking agent, and the like.
Regarding the main polymer composition, in the copolymer, the shear storage elastic modulus at normal temperature tends to decrease by increasing the ratio of the monomer to be a soft segment. On the contrary, the shear storage elastic modulus at room temperature tends to increase by increasing the ratio of the monomer that becomes the hard segment. Moreover, also in the composition, when the molecular weight of the polymer is lowered, the temperature range showing the rubber-like flat region is narrowed, so that the shear storage elastic modulus at normal temperature tends to be lowered. On the contrary, by increasing the molecular weight of the polymer, the temperature range showing the rubber-like flat region is widened, and the shear storage modulus at room temperature tends to increase. Generally, the tackifier has a high softening point of 60 degrees or more and a low molecular weight of about several thousand. By adding a tackifier, the cohesive strength of the adhesive composition is reduced, and a decrease in shear storage modulus at room temperature is observed. Moreover, the cohesive force of adhesive composition rises by mixing a crosslinking agent, and the raise of the shear storage elastic modulus in room temperature is seen.

  It is an essential requirement that the shear storage modulus at 23 ° C. of the composition, that is, the hot-melt adhesive is adjusted to 1 to 500 MPa. When the shear storage elastic modulus at 23 ° C. is less than 1 MPa, adhesiveness is exhibited at room temperature, and a paste residue is generated on the punching blade or the tab agent during post-processing such as punching of the laminated film. Conversely, when the shear storage modulus at 23 ° C. exceeds 500 MPa, it must be heated to a high temperature, for example, exceeding 110 ° C., in order to develop the tackiness necessary for laminating the film. If the temperature exceeds 110 ° C., the heat load on the film is too large and the film may be deformed. Moreover, the adhesive force with the film of an adhesive agent also falls. The shear storage modulus at 23 ° C. of the composition is preferably 2 to 300 MPa, more preferably 5 to 250 MPa.

  The shear storage modulus at 23 ° C. of the composition constituting the adhesive can be measured by the following method. The adhesive solution is taken into a measuring cup, put in a dryer at 80 ° C. for 10 hours and at 100 ° C. for 30 minutes to remove moisture, and a sample having a thickness of about 1.5 mm is produced. This sample is cut into a diameter of 8 mm and measured using a viscoelasticity measuring device (for example, Rheo Stress RS600 manufactured by Eihiro Seiki Co., Ltd.) at a temperature of 23 ° C., a frequency of 1 Hz, and a strain amount of 0.5%.

  In this invention, the adhesive agent may contain the filler other than the above-mentioned composition. There is no restriction | limiting in particular about a filler, The thing of various materials, shapes, and sizes can be used.

The filler material is not particularly limited, and inorganic and organic fillers can be appropriately selected and used.
Examples of the inorganic filler include glass, silicon oxide, aluminum hydroxide, aluminum oxide, titanium oxide, zinc oxide, barium sulfate, magnesium silicate, etc .;
Organic fillers include fluorine resin, polystyrene resin, acrylic resin, polycarbonate resin, silicone resin, polyethylene resin, ethylene-vinyl acetate copolymer, acrylonitrile, polyurethane, polyvinyl chloride, polyacrylonitrile, polyamide, polysiloxane resin, melamine resin , Benzoguanamine resin, or a cross-linked product thereof.

  The shape of the filler is not particularly limited, and examples thereof include a spherical shape, an ellipsoidal shape, a cubic shape, a needle shape, a rod shape, a spindle shape, a plate shape, a scale shape, and a fiber shape. Spherical or nearly ellipsoidal shape is preferable in that it can be achieved.

  The size of the filler is preferably 0.2 μm to 50 μm in diameter, more preferably 0.5 μm to 10 μm. In addition, when the diameter here is not a perfect sphere, the diameter of the sphere of the same volume is substituted. In the case of a filler having a significantly different size in one direction such as a needle shape, a diameter of a circle having the same area as the cross-sectional area of the cross section perpendicular to the direction is substituted.

  The refractive index of the filler is preferably different from the refractive index of the main polymer used as the base material of the adhesive, and the refractive index difference is more preferably 0.05 or more.

  The filler may be a single material, size, refractive index or other properties, or a mixture of two or more fillers. Moreover, you may use what consists of 2 or more types of raw materials as a filler.

  The content of the filler in the adhesive layer is preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polymer constituting the adhesive layer.

  The ratio between the average particle diameter d of the filler contained in the adhesive layer and the thickness l of the adhesive layer is preferably 0.05 ≦ d / l ≦ 0.6, particularly preferably 0.07 ≦ d / l ≦ 0. 3. If it is less than 0.05, the particle size of the filler is too small or the film thickness of the adhesive is too thick, so that if the former, the necessary scattering characteristics may not be obtained, but the latter does not require an adhesive layer. If the ratio exceeds 0.6, the required adhesion area cannot be obtained, the adhesion force is insufficient, and the adhesion layer may be peeled off.

The optical composite element of the present invention has excellent slipperiness due to the substrate having a predetermined uneven shape, and blocking is effective even if the production process includes a step of making the intermediate product into a roll shape. It is prevented and has excellent handling and storage. In particular, it is possible to wind up as it is without laminating a slippery protective film during winding. Therefore, the optical composite element of the present invention comprises a step of forming an alignment film layer on a substrate and then winding and rolling, and a resin layer having the cholesteric regularity on the substrate having the alignment film layer. The laminate obtained by coating and polymerizing can be manufactured by a manufacturing method including at least one of the steps of winding and forming a roll.
The step of forming a substrate having an alignment film layer into a roll, the step of forming a roll obtained by applying and polymerizing the resin layer having the cholesteric regularity on a substrate having an alignment film layer, Any of them can be carried out using a coating film forming apparatus provided with at least a winding device. For example, a liquid for forming an alignment film layer is applied to the substrate, dried and cured as necessary, and then wound by a winding device to prepare a roll of the substrate on which the alignment film is formed in advance. Subsequently, the base material on which the alignment film is formed from the roll is fed out, and the laminate obtained by applying and polymerizing the resin layer having the cholesteric regularity on the base material having the alignment film layer is used again with a winding device. To form a roll of the laminate. The winding method is not particularly limited, and a winding method such as near winding or touch winding can be appropriately selected and applied.

  In the optical composite element of the present invention, the haze of both the base material and / or the adhesive layer, preferably at least the adhesive layer, is preferably 10% to 90%, particularly preferably 30% to 80%. If it is less than 10%, there is a possibility that a sharp luminance change caused by a change in the observation angle of the emitted light, that is, a so-called glare, is visually recognized through the optical multi-layer element. The expected brightness may not be obtained due to scattering. Examples of the method for setting the haze in the above range include a method of dispersing the light diffusing agent in the adhesive layer or the base material, and a method of forming an uneven shape on the surface of the adhesive layer or the base material. The haze can be adjusted by adjusting the dispersion amount of the light diffusing agent when dispersing the light diffusing agent, and by adjusting the size and density of the concavo-convex shape when forming the concavo-convex shape. In addition, the measurement of haze is performed using a haze meter (for example, haze guard II (made by Toyo Seiki Co., Ltd.)).

The optical composite element of the present invention can be used as a component of a liquid crystal display device such as a liquid crystal display device. Specifically, for example, a liquid crystal display device that includes a light source and the optical composite element of the present invention, and further includes a prism sheet on the light source side with respect to the optical composite element. It can be disposed between the backlight of the liquid crystal display device and the liquid crystal cell to achieve improved luminance. More specifically, a prism sheet is further arranged between the light source and the optical composite element so that the surface on the reflective polarizing element side faces the light source side and the surface on the optical anisotropic element side faces the liquid crystal cell side. Thus, the linearly polarized light emitted from the optically anisotropic element can enter the liquid crystal cell. When a polarizing plate is disposed between the optically anisotropic layer and the liquid crystal cell, the optical composite element of the present invention usually has a polarization plane of linearly polarized light emitted from the reflective polarizing element and a transmission axis of the polarizing plate. Arranged to be parallel.
The prism sheet collects light emitted from a light source, and includes, for example, a sheet in which a large number of fine prisms are formed on a plastic sheet. The arrangement pattern of the prisms may be regular or irregular. Further, the regular / irregular period of the prism may be only in one direction within the plane, or may be in a plurality of directions. The magnitude of the period is usually 1 μm to 1000 μm. Examples of the cross-sectional shape of the prism include a sawtooth shape, a wave shape, and a semicircular shape, and the ridge portion may be R-processed. When the prism sheet is arranged in the liquid crystal display device, the prism sheet is usually arranged so that the prism faces the liquid crystal cell side. The thickness of the prism sheet is usually 1 mm or less, preferably 5 to 500 μm, more preferably 10 to 200 μm.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited to the following Example.

Examples 1-3 and Comparative Examples 1-2
(Reflective polarizing element)
One side of a ZEONOR film (manufactured by Optes Co., Ltd.) having a thickness of 100 μm, a width of 50 mm, and a length of 200 mm was subjected to corona discharge treatment so that the wetting index of the surface was 56 dyne / cm. This was used as a substrate film. About Example 1- Example 3, before performing a corona discharge process, the haze of a base film is 5% [Example 1], 40% [Example 2] on the surface opposite to the treatment surface in advance. The embossing process was performed so that it might become 70% [Example 3], and the uneven | corrugated shape (The dot pattern shape of the diameter of 15 micrometers arrange | positioned at random) was formed. The haze of the base film was adjusted by changing the density of the dot pattern shape constituting the uneven shape. In Comparative Example 1 and Comparative Example 2, the above-described embossing treatment was not performed.

  An alignment film composition comprising a modified polyamide (weight average molecular weight 45,000) having the following composition, a crosslinking agent and a solvent (solvent composition 100% by weight) is applied to the surface of the base film subjected to corona discharge treatment. It applied using wire bar # 4. After coating, the film was dried at 120 ° C. for 5 minutes to produce a dry film having a thickness of 0.2 μm.

[Composition for alignment film]
Modified polyamide:
FR105 (Lead City, Fine Resin, partially methoxymethylated polyamide)
90 parts by weight / A90 (Toray Industries, Inc., AQ-nylon, partially alkylated polyamide)
10 parts by weight solvent:
1-propanol 3233 parts by weight crosslinking agent:
-Elastron BN04 1.0 part by weight

  The dry film was rubbed in one direction to obtain an alignment film. On the prepared alignment film, a coating solution having the following composition was applied using a wire bar # 6, dried at 100 ° C. for 5 minutes, and subjected to orientation aging.

[Coating liquid composition for forming cholesteric resin layer]
Solid content: 40% by weight
Liquid crystalline compound (rod-like liquid crystal having Δn (= ne-no) = 0.18) 93.0 parts by weight Photopolymerization initiator (IRG907 manufactured by Ciba Specialty Chemicals) 3.1 parts by weight Surfactant (Seimi Chemical) Co., Ltd. KH-40) 0.11 parts by weight Chiral agent (LC756, manufactured by BASF) 6.7 parts by weight Methyl ethyl ketone 154.8 parts by weight

The coating film was irradiated with ultraviolet rays of 70 mJ / cm ² (UV-A), held at 100 ° C. for 1 to 5 minutes, then irradiated with ultraviolet rays to cure the coating film, and a cholesteric resin layer having a thickness of 3 μm ( A circularly polarized light separating sheet 1 having an optical functional layer) was obtained. This cholesteric resin layer has an average value of light transmittance from 400 nm to 570 nm of about 55%, and it was found that the remaining 45% including interface reflection is reflected.

  In the production of the circularly polarized light separating sheet 1, the same procedure was performed except that 93.0 parts by weight of the polymerizable liquid crystal compound was changed to 95.2 parts by weight and 6.7 parts by weight of the chiral agent was changed to 4.8 parts by weight. A circularly polarized light separating sheet 2 was obtained. This cholesteric resin layer had an average light transmittance of about 55% from 560 to 730 nm, and it was found that the remaining 45% including the interface reflection was reflected.

  The cholesteric resin layer side of the produced circularly polarized light separating sheet 2 was bonded and fixed to the base film side of the circularly polarized light separating sheet 1 to obtain a circularly polarized light separating element.

(Optically anisotropic layer)
A monomer composition composed of 97.8% by weight of methyl methacrylate and 2.2% by weight of methyl acrylate was polymerized by a bulk polymerization method to obtain resin pellets.

  Rubber particles were produced according to Example 3 of JP-B-55-27576. This rubber particle has a spherical three-layer structure, the core inner layer is a crosslinked polymer of methyl methacrylate and a small amount of allyl methacrylate, and the inner layer is composed of butyl acrylate and styrene as main components and a small amount of acrylic acid. It is a soft elastic copolymer obtained by crosslinking and copolymerizing allyl, and the outer layer is a hard polymer of methyl methacrylate and a small amount of ethyl acrylate. The average particle size of the inner layer was 0.19 μm, and the particle size including the outer layer was 0.22 μm.

  70 parts by weight of the resin pellets and 30 parts by weight of the rubber particles were mixed and melt kneaded with a twin screw extruder to obtain a methacrylic acid ester polymer composition A (glass transition temperature 105 ° C.).

  By coextruding the methacrylic ester polymer composition A (b layer) and the styrene maleic anhydride copolymer (glass transition temperature 130 ° C.) (a layer) at a temperature of 280 ° C., a b layer / a layer A multilayer film having an average thickness of 45/70/45 (μm) with a three-layer structure of / b layers was obtained. The laminated film is stretched obliquely at a stretching temperature of 134 ° C. and a stretching ratio of 1.8 times so that the slow axis is in a direction inclined by 45 degrees with respect to the MD direction by a tenter stretching machine. Got.

  The retardation in the front direction of the optically anisotropic layer was 140 nm, and the retardation in the thickness direction was −85 nm (each numerical value is a measured value after stretching). Further, one side of the optically anisotropic layer was subjected to corona discharge treatment so that the wetting index was 56 dyne / cm.

  Next, the reflective polarizing element and the optically anisotropic layer were bonded and integrated with an adhesive (Example) or a pressure-sensitive adhesive (pressure-sensitive adhesive) to produce an optical composite element.

  For the adhesive (Example), first, ethylene-vinyl acetate copolymer emulsion (non-volatile content 40% by weight, vinyl acetate content 40% by weight) 40 parts by weight, petroleum resin emulsion (non-volatile content 40% by weight, resin softening point) An adhesive composition having a shear storage elastic modulus at 23 ° C. of 10 MPa, comprising 35 parts by weight of 85 ° C.) and 10 parts by weight of a paraffin wax emulsion (non-volatile content 40% by weight, resin softening point 64 ° C.) was prepared. For Example 1, Example 2, and Comparative Example 1, the adhesive composition was directly laminated on the cholesteric resin layer of the reflective polarizing element so as to have an average thickness of 20 μm. The corona-treated surface was bonded using a laminator at a nip pressure of 80 ° C. and 2 kgf / 50 mm to obtain an optical composite element. On the other hand, for Example 3 and Comparative Example 1, fine particles (shape: spherical, material: polystyrene, refractive index: 1.59) having a diameter of 4 μm were added to the adhesive composition so that the haze was 40% and 70%, respectively. The mixture was laminated and bonded on the cholesteric resin layer of the reflective polarizing element in the same manner as in Example 1 to obtain an optical composite element.

About the obtained composition, each item of Table 1 was evaluated.
Haze was measured according to JIS K7136 using Hazeguard II (manufactured by Toyo Seiki Co., Ltd.). The case where the haze exceeded 5% was evaluated as “Yes”, and the case where the haze was 5% or less was evaluated as “None”.

  The brightness is obtained by disassembling a commercially available liquid crystal display device (manufactured by Sharp, AQUAS, LC-37BE1W), reassembling the brightness enhancement films of Examples and Comparative Examples, and displaying the liquid crystal display device in white, and the front surface at that time The luminance in the direction was measured using a viewing angle measurement and evaluation apparatus (manufacturer: Autronic-MELCHERS, trade name: ErgoScope). The liquid crystal display device includes a light source, a diffusion plate, a diffusion sheet, a prism sheet, an optical composite element, and a liquid crystal panel in this order. The measurement result of Example 1 is set to 1, and the measurement results of other examples and comparative examples are shown in Table 1 as relative values.

The slipperiness is determined when the base material after the formation of the alignment film layer of the circularly polarized light separating sheet 2 is in a roll state, and the laminate after coating and polymerizing a resin layer having cholesteric regularity on the alignment film is set in a roll state. In this case, the case where no blocking occurs is indicated as ◯, and the case where the blocking occurs is indicated as ×. In Table 1, “Slip property with alignment layer” represents the evaluation of slip property when the substrate after forming the alignment layer of the circularly polarized light separating sheet 2 is in a roll state, and “Slip with resin layer” “Performance” represents an evaluation of slipperiness when the laminate after coating and polymerization of a resin layer having cholesteric regularity on the alignment film is in a roll state.
The glare and color unevenness were visually evaluated in the same mounting state as the luminance measurement. In the case of glare, the case where the steep luminance change when the observation angle was changed was eliminated was judged as ◯, and the case where it was not eliminated was judged as x. Color unevenness was evaluated as ◯ when not observed, Δ when observed but mild, and × when observed and markedly deteriorated display quality.

Claims (5)

An optical composite element in which a reflective polarizing element including a resin layer having cholesteric regularity and an optically anisotropic element having a retardation in the front direction of approximately ¼ wavelength are integrated,
The resin layer having the cholesteric regularity is formed by applying and polymerizing a composition containing a polymerizable liquid crystal compound on a substrate having an alignment film layer,
The base material has an uneven shape on the side opposite to the alignment film layer,
Optical composite element.   The optical composite element according to claim 1, wherein the optically anisotropic element has a thickness direction retardation Rth of less than 0 nm. Having an adhesive layer between the reflective polarizing element and the optically anisotropic element;
The optical composite element of Claim 1 or 2 whose haze value of the said contact bonding layer and / or a base material is 10%-90%. A laminate obtained by forming an alignment film layer on a substrate and then winding it up to form a roll, and applying and polymerizing the resin layer having the cholesteric regularity on the substrate having the alignment film layer The method for producing an optical composite element according to any one of claims 1 to 3, wherein the optical composite element is produced by a production method including at least one of the steps of winding the material into a roll. A liquid crystal display device comprising a light source and the optical composite element according to claim 1,
Furthermore, the optical composite element is provided with a prism sheet on the light source side,
Liquid crystal display device.