JP6905350B2 - Liquid crystal display device and optical members - Google Patents

Description

The present invention relates to a liquid crystal display device and an optical member.

As an image display device with low power consumption and space saving, the spread of liquid crystal display devices is remarkable. With the widespread use of liquid crystal display devices, there is a continuous demand for thinner, larger, and higher definition liquid crystal display devices. Furthermore, in recent years, there has been an increasing demand for higher color rendering (wider color gamut) of liquid crystal display devices. However, since a configuration that can realize a wide color gamut is very expensive, an inexpensive alternative technology is strongly demanded.

Japanese Unexamined Patent Publication No. 2002-040233

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a liquid crystal display device having high color rendering properties and high brightness and which can be realized at low cost. be.

The liquid crystal display device of the present invention includes a liquid crystal cell, a viewing side adhesive layer and a viewing side polarizing plate arranged in order from the liquid crystal cell side on the viewing side of the liquid crystal cell, and the liquid crystal cell on the back side of the liquid crystal cell. It includes a back-side adhesive layer, a back-side polarizing plate, and a reflective polarizer arranged in order from the side, and has a wavelength-selective absorption layer on either the visual side or the back side of the liquid crystal cell.
In one embodiment, the visible side pressure-sensitive adhesive layer functions as the wavelength selective absorption layer.
In one embodiment, the liquid crystal display device has the wavelength selective absorption layer on the side opposite to the back side polarizing plate of the reflective polarizer. In one embodiment, the wavelength selective absorption layer has an anti-blocking function. In one embodiment, the arithmetic mean roughness Ra of the surface of the wavelength selective absorption layer opposite to the reflective polarizer is 20 nm or more.
In one embodiment, the liquid crystal display device further includes a retardation layer having an in-plane retardation Re (550) of 100 nm to 200 nm between the reflective polarizer and the wavelength selective absorption layer. In one embodiment, the angle formed by the absorption axis of the polarizer of the back-side polarizing plate and the slow axis of the retardation layer is 40 ° to 50 °.
In one embodiment, the wavelength selective absorption layer comprises a wavelength selective absorption material having an absorption maximum wavelength in a wavelength band in the range of 570 nm to 610 nm.
According to another aspect of the present invention, an optical member is provided. This optical member has a wavelength selective absorption layer, a reflective polarizing element, a polarizing plate, and an adhesive layer in this order, and is attached to the back surface side of the liquid crystal cell via the adhesive layer.

According to the present invention, by introducing a reflective polarizing element in combination with a predetermined wavelength selective absorption layer, it is possible to obtain a liquid crystal display device having high color rendering properties and high brightness and which can be realized at low cost. can.

It is schematic cross-sectional view explaining the liquid crystal display device by one Embodiment of this invention. It is schematic cross-sectional view explaining the liquid crystal display device by another embodiment of this invention. It is a schematic perspective view which shows an example of the reflection type polarizer which can be used in embodiment of this invention.

A. Overall Configuration of Liquid Crystal Display Device First, a typical embodiment of the overall configuration of the liquid crystal display device will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and duplicate description will be omitted. Also, for the sake of clarity, the thickness ratio of each layer in the drawing is different from the actual one. The components of the liquid crystal display device will be described in detail in Sections B to H.

FIG. 1 is a schematic cross-sectional view illustrating a liquid crystal display device according to one embodiment of the present invention. The liquid crystal display device 100 of the present embodiment includes a liquid crystal cell 10, a viewing side adhesive layer 21 and a viewing side polarizing plate 31 arranged in order from the liquid crystal cell 10 side on the viewing side of the liquid crystal cell 10, and a back surface of the liquid crystal cell 10. A back surface adhesive layer 22, a back surface polarizing plate 32, and a reflective polarizing element 40 are provided on the side in order from the liquid crystal cell 10 side. In the present embodiment, the visible side pressure-sensitive adhesive layer 21 functions as a wavelength selective absorption adhesive layer (hereinafter, the visible side pressure-sensitive adhesive layer 21 in the present embodiment is referred to as a wavelength selective absorption pressure-sensitive adhesive layer).

FIG. 2 is a schematic cross-sectional view illustrating a liquid crystal display device according to another embodiment of the present invention. The liquid crystal display device 101 of the present embodiment includes a liquid crystal cell 10, a viewing side adhesive layer 23 and a viewing side polarizing plate 31 arranged in order from the liquid crystal cell 10 side on the viewing side of the liquid crystal cell 10, and a back surface of the liquid crystal cell 10. A back surface adhesive layer 22, a back surface polarizing plate 32, a reflective polarizer 40, and a wavelength selective absorption layer 50, which are arranged in order from the liquid crystal cell 10 side, are provided on the side. As shown in the illustrated example, a retardation layer 60 may be provided between the reflective polarizer 40 and the wavelength selective absorption layer 50, if necessary. The optical characteristics (for example, refractive index characteristics, in-plane retardation, thickness direction retardation, Nz coefficient, photoelasticity coefficient, wavelength dispersion characteristics), number, combination, arrangement order, etc. of the retardation layer 60 are appropriate according to the purpose. Can be set to. In the present embodiment, the visible side pressure-sensitive adhesive layer 23 is a normal pressure-sensitive adhesive layer that does not substantially have a wavelength selective absorption function. In the present embodiment, the wavelength selective absorption layer 50 may have an anti-blocking function. In the present specification, "the wavelength selective absorption layer has an anti-blocking function" means that the wavelength selective absorption layer 50 itself has an anti-blocking function and the surface of the wavelength selective absorption layer 50 on the opposite side to the reflective polarizer. Includes a configuration in which an anti-blocking layer is formed.

Each of the above components may be sequentially laminated to the liquid crystal cell as a single film or layer, or may be laminated to the liquid crystal cell as a laminate of a plurality of films and / or layers. For example, an optical member having a polarizing plate and a wavelength selective absorption pressure-sensitive adhesive layer (a polarizing plate with a wavelength selective absorption pressure-sensitive adhesive layer) may be laminated on the visible side of the liquid crystal cell via the wavelength selection absorption pressure-sensitive adhesive layer. An optical member having a wavelength selective absorption layer, a reflective polarizing element, a polarizing plate, and an adhesive layer in this order may be laminated on the back surface side of the liquid crystal cell via the adhesive layer. Therefore, these optical members can also be included in the present invention. Further, a polarizing plate with an adhesive layer and an optical member including a wavelength selective absorption layer and a reflective polarizer may be sequentially laminated on the back surface side of the liquid crystal cell.

The liquid crystal display device of any of the embodiments typically further includes a backlight unit (not shown) on the opposite side of the reflective polarizer 40 or the wavelength selective absorption layer 50 to the liquid crystal cell 10. The backlight unit may adopt any suitable configuration. For example, the backlight unit may be of an edge light type or a direct type. When the direct method is adopted, the backlight unit includes, for example, a light source, a reflective film, a diffuser plate, and the above-mentioned optical member. When the edge light method is adopted, the backlight unit may further include a light guide plate and a light reflector. The light source may have any suitable configuration depending on the purpose. Since the specific configuration of the backlight unit is well known in the art, detailed description thereof will be omitted.

The above embodiments may be combined as appropriate, and the components of the above embodiments may be modified in the art.

B. Visible side adhesive layer B-1. Wavelength Selective Absorption Adhesive Layer The wavelength selective absorption adhesive layer 21 typically includes a pressure-sensitive adhesive as a matrix and a wavelength-selective absorption material dispersed in the pressure-sensitive adhesive.

B-1-1. Adhesive As the adhesive, any suitable adhesive can be used. The pressure-sensitive adhesive preferably has low oxygen permeability and moisture permeability, high photostability and chemical stability, has a predetermined refractive index, has excellent transparency, and / or. , Has excellent dispersibility with respect to wavelength selective absorption materials.

Specific examples of the pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives, acrylic-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, and cellulose-based pressure-sensitive adhesives. A rubber-based pressure-sensitive adhesive or an acrylic-based pressure-sensitive adhesive is preferable.

The rubber-based polymer of the rubber-based pressure-sensitive adhesive (adhesive composition) is a polymer that exhibits rubber elasticity in a temperature range near room temperature. Preferred rubber-based polymers (A) include styrene-based thermoplastic elastomers (A1), isobutylene-based polymers (A2), and combinations thereof.

Examples of the styrene-based thermoplastic elastomer (A1) include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-butadiene-styrene block copolymer. (SBS), Styrene-ethylene-propylene-Styrene block copolymer (SEPS, SIS hydrogenated product), Styrene-ethylene-propylene block copolymer (SEP, Styrene-Isoprene block copolymer hydrogenated product), Examples thereof include styrene-based block copolymers such as styrene-isobutylene-styrene block copolymer (SIBS) and styrene-butadiene rubber (SBR). Among these, styrene-ethylene-propylene-styrene block copolymer (supposition of SEPS and SIS) and styrene-ethylene- because they have polystyrene blocks at both ends of the molecule and have high cohesiveness as a polymer. Butylene-styrene block copolymer (SEBS) and styrene-isobutylene-styrene block copolymer (SIBS) are preferable. A commercially available product may be used as the styrene-based thermoplastic elastomer (A1). Specific examples of commercially available products include SEPTON and HYBRAR manufactured by Kuraray Corporation, Tough Tech manufactured by Asahi Kasei Chemicals Co., Ltd., and SIBSTAR manufactured by Kaneka Corporation.

The weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is preferably about 50,000 to 500,000, more preferably about 50,000 to 300,000, and even more preferably about 50,000 to 250,000. When the weight average molecular weight of the styrene-based thermoplastic elastomer (A1) is in such a range, it is preferable because both the cohesive force of the polymer and the viscoelasticity can be achieved.

The styrene content in the styrene-based thermoplastic elastomer (A1) is preferably about 5% by weight to 70% by weight, more preferably about 5% by weight to 40% by weight, still more preferably 10% by weight to 20% by weight. It is about% by weight. When the styrene content in the styrene-based thermoplastic elastomer (A1) is in such a range, viscoelasticity due to the soft segment can be ensured while maintaining the cohesive force due to the styrene moiety, which is preferable.

Examples of the isobutylene polymer (A2) include those containing isobutylene as a constituent monomer and having a weight average molecular weight (Mw) of preferably 500,000 or more. The isobutylene-based polymer (A2) may be a homopolymer of isobutylene (polyisobutylene, PIB), and is a copolymer containing isobutylene as a main monomer (that is, a copolymer in which isobutylene is copolymerized in a proportion of more than 50 mol%). There may be. Examples of such copolymers include copolymers of isobutylene and normal butylene, copolymers of isobutylene and isoprene (for example, butyl rubbers such as regular butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and partially crosslinked butyl rubber). Examples thereof include these vulcanized products and modified products (for example, those modified with functional groups such as hydroxyl group, carboxyl group, amino group and epoxy group). Among these, polyisobutylene (PIB) is preferable because it does not contain a double bond in the main chain and has excellent weather resistance. A commercially available product may be used as the isobutylene polymer (A2). Specific examples of commercially available products include OPPANOL manufactured by BASF.

The weight average molecular weight (Mw) of the isobutylene polymer (A2) is preferably 500,000 or more, more preferably 600,000 or more, and further preferably 700,000 or more. The upper limit of the weight average molecular weight (Mw) is preferably 5 million or less, more preferably 3 million or less, and further preferably 2 million or less. By setting the weight average molecular weight of the isobutylene polymer (A2) to 500,000 or more, a pressure-sensitive adhesive composition having more excellent durability during high-temperature storage can be obtained.

The content of the rubber-based polymer (A) in the pressure-sensitive adhesive (pressure-sensitive adhesive composition) is preferably 30% by weight or more, more preferably 40% by weight or more, and further, based on the total solid content of the pressure-sensitive adhesive composition. It is preferably 50% by weight or more, and particularly preferably 60% by weight or more. The upper limit of the content of the rubber-based polymer is preferably 95% by weight or less, and more preferably 90% by weight or less.

In the rubber-based pressure-sensitive adhesive, the above-mentioned rubber-based polymer (A) and another rubber-based polymer may be used in combination. Specific examples of other rubber-based polymers include butyl rubber (IIR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), EPR (binary ethylene-propylene rubber), and EPT (ternary ethylene-propylene rubber). ), Acrylic rubber, urethane rubber, polyurethane-based thermoplastic elastomer; polyester-based thermoplastic elastomer; blend-based thermoplastic elastomer such as a polymer blend of polypropylene and EPT (ternary ethylene-propylene rubber). The blending amount of the other rubber-based polymer is preferably about 10 parts by weight or less with respect to 100 parts by weight of the rubber-based polymer (A).

The acrylic polymer of the acrylic pressure-sensitive adhesive (tacking agent composition) typically contains an alkyl (meth) acrylate as a main component, and as a copolymerization component according to the purpose, an aromatic ring-containing (meth) acrylate, It may contain an amide group-containing monomer, a carboxyl group-containing monomer and / or a hydroxyl group-containing monomer. As used herein, the term "(meth) acrylate" means acrylate and / or methacrylate. Examples of the alkyl (meth) acrylate include those having a linear or branched alkyl group having 1 to 18 carbon atoms. Aromatic ring-containing (meth) acrylate is a compound having an aromatic ring structure in its structure and containing a (meth) acryloyl group. Examples of the aromatic ring include a benzene ring, a naphthalene ring, and a biphenyl ring. The aromatic ring-containing (meth) acrylate can satisfy durability (particularly, durability against a transparent conductive layer) and can improve display unevenness due to white spots in the peripheral portion. The amide group-containing monomer is a compound containing an amide group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. A carboxyl group-containing monomer is a compound containing a carboxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. A hydroxyl group-containing monomer is a compound containing a hydroxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Details of the acrylic pressure-sensitive adhesive are described in, for example, Japanese Patent Application Laid-Open No. 2015-199942, and the description of the publication is incorporated herein by reference.

B-1-2. Wavelength Selective Absorption Material A typical example of the wavelength selective absorption material is a wavelength selective absorption dye. As the wavelength selective absorption dye, any suitable wavelength selective absorption dye can be used. Specific examples of wavelength selective absorption dyes include anthraquinone, triphenylmethane, naphthoquinone, thioindigo, perinone, perylene, squarylium, cyanine, porphyrin, azaporphyrin, phthalocyanine, and subphthalocyanine. , Quinoline, Polymethin, Rhodamine, Oxonol, Kinone, Azo, Xanthene, Azomethin, Kinacridone, Dioxazine, Diketopyrrolopyrrole, Anthraquinone, Isoindrinone, Indanslon , Indigo-based, thioindigo-based, quinophthalone-based, quinoline-based, and triphenylmethane-based compounds.

The wavelength selective absorption material may be used alone or in combination of two or more. When the wavelength selective absorption material is used alone, the wavelength selective absorption material preferably has an absorption maximum wavelength in a wavelength band in the range of 570 nm to 610 nm. With such a configuration, mixing of red light and green light can be satisfactorily prevented. As a result, very good color rendering properties can be realized. When two types of wavelength selective absorption materials are used in combination, typically, the above wavelength selective absorption material (first wavelength selective absorption material) and another wavelength selective absorption material (second wavelength selective absorption material) are used. Can be used in combination with. As described above, the first wavelength selective absorption material preferably has an absorption maximum wavelength in the wavelength band of 570 nm to 610 nm, and the second wavelength selective absorption material preferably has a wavelength band in the range of 470 nm to 500 nm. It has an absorption maximum wavelength. With such a configuration, not only the mixing of red light and green light but also the mixing of green light and blue light can be satisfactorily prevented. As a result, even better color rendering properties can be realized. Examples of the first wavelength selective absorption material include indigo-based, rhodamine-based, quinacridone-based, and porphyrin-based compounds. Examples of the second wavelength selective absorption material include anthraquinone-based, oxime-based, naphthoquinone-based, quinizarin-based, oxonor-based, azo-based, xanthene-based, and phthalocyanine-based compounds. Needless to say, three or more kinds of wavelength selective absorption materials may be used in combination depending on the purpose.

The wavelength selective absorption material may also preferably have luminescence. There is an advantage that the brightness can be improved by using the wavelength selective absorption material having luminescent property.

The content of the wavelength selective absorption material in the wavelength selective absorption pressure-sensitive adhesive layer (the total content when two or more kinds are used) is preferably 0.01 part by weight or more with respect to 100 parts by weight of the solid content of the pressure-sensitive adhesive. It is 100 parts by weight, more preferably 0.01 parts by weight to 50 parts by weight, and further preferably 0.1 parts by weight to 10 parts by weight. Within such a range, both high brightness and high color gamut (high color rendering properties) can be achieved at the same time.

B-1--3. The other wavelength selective absorption pressure-sensitive adhesive layer (substantially, the pressure-sensitive adhesive) may further contain any suitable additive depending on the purpose. Examples of the additive include a light diffusing material, a material that imparts anisotropy to light, and a material that polarizes light. Specific examples of the light diffusing material include fine particles composed of an acrylic resin, a silicone resin, a styrene resin, or a copolymer resin thereof. Specific examples of the material that imparts anisotropy to light and / or the material that polarizes light include elliptical spherical fine particles, core-shell fine particles, and laminated fine particles having different birefringences on the major axis and the minor axis. The type, number, blending amount, etc. of the additive can be appropriately set according to the purpose.

The thickness of the wavelength selective absorption pressure-sensitive adhesive layer is preferably 10 μm to 100 μm, and more preferably 20 μm to 60 μm.

B-2. Normal Visible Adhesive Layer The normal visible adhesive layer 23 is the same as the wavelength selective absorption adhesive layer described in Section B-1 except that it does not contain a wavelength selective absorption material.

C. Viewing-side polarizing plate The viewing-side polarizing plate 31 typically includes an absorption-type polarizing element and a protective layer arranged on at least one side of the absorption-type polarizing element.

C-1. Polarizer As the absorptive polarizer, any suitable polarizer can be adopted. For example, the resin film forming the polarizer may be a single-layer resin film or a laminated body having two or more layers.

Specific examples of the polarizer composed of a single-layer resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer system partially saponified film. Examples thereof include those which have been dyed and stretched with a bicolor substance such as iodine or a bicolor dye, and polyene-based oriented films such as a dehydrated product of PVA and a dehydrogenated product of polyvinyl chloride. Preferably, since the PVA-based film is excellent in optical characteristics, a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching the film is used.

The dyeing with iodine is performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment or while dyeing. Alternatively, it may be stretched and then dyed. If necessary, the PVA-based film is subjected to a swelling treatment, a cross-linking treatment, a washing treatment, a drying treatment and the like. For example, by immersing the PVA-based film in water and washing it with water before dyeing, it is possible not only to clean the dirt on the surface of the PVA-based film and the blocking inhibitor, but also to swell the PVA-based film to prevent uneven dyeing. Can be prevented.

Specific examples of the polarizer obtained by using the laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the resin. Examples thereof include a polarizer obtained by using a laminate with a PVA-based resin layer coated and formed on a base material. The polarizer obtained by using the laminate of the resin base material and the PVA-based resin layer coated and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying the resin base material. It is produced by forming a PVA-based resin layer on the PVA-based resin layer to obtain a laminate of a resin base material and a PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further include, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. The obtained resin substrate / polarizer laminate may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), and the resin substrate is peeled off from the resin substrate / polarizer laminate. Then, an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface. Details of the method for producing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. The entire description of the publication is incorporated herein by reference.

In one embodiment, the thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 12 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained. In another embodiment, the thickness of the polarizer is preferably more than 15 μm and 30 μm or less.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the polarizer is 43.0% to 46.0%, preferably 44.5% to 46.0%, as described above. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

The single transmittance and the degree of polarization can be measured using a spectrophotometer. As a specific method for measuring the degree of polarization, the parallel transmittance (H ₀ ) and the orthogonal transmittance (H ₉₀ ) of the polarizer are measured, and the formula: degree of polarization (%) = {(H ₀ −H _90). ) / (H ₀ + H ₉₀ )} ^1/2 × 100. The parallel transmittance (H ₀ ) is a value of the transmittance of a parallel laminated polarizing element produced by superimposing two identical polarizers so that their absorption axes are parallel to each other. Further, the orthogonal transmittance (H ₉₀ ) is a value of the transmittance of an orthogonal laminated polarizer produced by superimposing two identical polarizers so that their absorption axes are orthogonal to each other. These transmittances are Y values obtained by correcting the luminosity factor with the 2 degree field of view (C light source) of JlS Z 8701-1982.

C-2. Protective layer The protective layer is formed of any suitable film that can be used as a protective film for the polarizing plate. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based. , Polyester-based, polycarbonate-based, polyolefin-based, (meth) acrylic-based, acetate-based transparent resins and the like. Further, thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone, or ultraviolet curable resins can also be mentioned. In addition to this, for example, glassy polymers such as siloxane-based polymers can also be mentioned. Further, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Can be used, and examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the above resin composition.

When a protective layer is provided on the visible side of the polarizer, the protective layer may be subjected to surface treatment such as hard coating treatment, antireflection treatment, anti-sticking treatment, and anti-glare treatment, if necessary. Further / or, if necessary, the protective layer is provided with a process for improving visibility when visually recognizing through polarized sunglasses (typically, a (elliptical) circularly polarized light function is provided, and an ultra-high phase difference is provided. May be given). By performing such a process, excellent visibility can be realized even when the display screen is visually recognized through a polarized lens such as polarized sunglasses. Therefore, the liquid crystal display device can be suitably used outdoors.

When a protective layer is provided on the liquid crystal cell side of the polarizer, the protective layer is preferably optically isotropic. As used herein, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. say. Here, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C., and "Rth (550)" is a position in the thickness direction measured with light having a wavelength of 550 nm at 23 ° C. It is a phase difference. When the thickness of the layer (film) is d (nm), Re (550) is obtained by the formula: Re (λ) = (nx-ny) × d, and Rth (550) is calculated by the formula: Rth (λ). ) = (Nx−nz) × d. Note that "nx" is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), and "ny" is the in-plane direction orthogonal to the slow-phase axis (that is, the phase-advancing axis). The refractive index in the direction), and “nz” is the refractive index in the thickness direction.

The thickness of the protective layer is preferably 20 μm to 100 μm. The protective layer may be laminated on the polarizer via an adhesive layer (specifically, an adhesive layer or an adhesive layer), or may be laminated in close contact with the polarizer (without an adhesive layer). good. The adhesive layer is formed with any suitable adhesive. Examples of the adhesive include a water-soluble adhesive containing a polyvinyl alcohol-based resin as a main component. The water-soluble adhesive containing a polyvinyl alcohol-based resin as a main component may preferably further contain a metal compound colloid. The metal compound colloid may be one in which the metal compound fine particles are dispersed in a dispersion medium, and may be electrostatically stabilized due to mutual repulsion of the same kind of charges of the fine particles, and may have permanent stability. .. The average particle size of the fine particles forming the metal compound colloid can be any appropriate value as long as it does not adversely affect the optical characteristics such as the polarization characteristics. It is preferably 1 nm to 100 nm, more preferably 1 nm to 50 nm. This is because the fine particles can be uniformly dispersed in the adhesive layer, the adhesiveness can be ensured, and the knick can be suppressed. The "knick" refers to a local uneven defect that occurs at the interface between the polarizer and the protective layer. The pressure-sensitive adhesive layer is composed of any suitable pressure-sensitive adhesive.

D. Back side pressure-sensitive adhesive layer The back side pressure-sensitive adhesive layer 22 is the same as the wavelength-selective absorption pressure-sensitive adhesive layer described in Section B-1 except that it does not contain a wavelength-selective absorption material.

E. Back-side polarizing plate The back-side polarizing plate 32 also typically has an absorption-type polarizing element and a protective layer arranged on at least one side of the absorption-type polarizer. The absorption type polarizer and the protective layer are the same as those for the viewing side polarizing plate. However, in the back side polarizing plate, neither the liquid crystal cell side nor the back side protective layer is subjected to the surface treatment as described in the above item C-2.

F. Reflective Polarizer The reflective polarizing element 40 has a function of transmitting polarized light in a specific polarized state (polarization direction) and reflecting light in other polarized states. The reflective polarizer 40 may be a linearly polarized light separated type or a circularly polarized light separated type. Hereinafter, as an example, a linearly polarized light separation type reflective polarizer will be described. Examples of the circularly polarized light separation type reflective polarizer include a laminate of a film on which a cholesteric liquid crystal is immobilized and a λ / 4 plate.

FIG. 3 is a schematic perspective view of an example of a reflective polarizer. The reflective polarizer is a multilayer laminate in which a layer A having birefringence and a layer B having substantially no birefringence are alternately laminated. For example, the total number of layers of such a multi-layer laminate can be 50-1000. In the illustrated example, the refractive index nx in the x-axis direction of the A layer is larger than the refractive index ny in the y-axis direction, and the refractive index nx in the x-axis direction of the B layer and the refractive index ny in the y-axis direction are substantially the same. be. Therefore, the difference in refractive index between the A layer and the B layer is large in the x-axis direction and substantially zero in the y-axis direction. As a result, the x-axis direction becomes the reflection axis, and the y-axis direction becomes the transmission axis. The difference in refractive index between the A layer and the B layer in the x-axis direction is preferably 0.2 to 0.3. The x-axis direction corresponds to the stretching direction of the reflective polarizer in the method for manufacturing the reflective polarizer.

The layer A is preferably composed of a material that exhibits birefringence by stretching. Typical examples of such materials include polyester naphthalenedicarboxylic acid (eg, polyethylene naphthalate), polycarbonate and acrylic resins (eg, polymethylmethacrylate). Polyethylene naphthalate is preferred. The B layer is preferably composed of a material that does not substantially exhibit birefringence even when stretched. A typical example of such a material is a copolyester of naphthalenedicarboxylic acid and terephthalic acid.

The reflective polarizing element transmits light having a first polarization direction (for example, a p wave) at the interface between the A layer and the B layer, and has a second polarization direction orthogonal to the first polarization direction. Reflects light (eg, s waves). At the interface between the A layer and the B layer, the reflected light is partially transmitted as light having a first polarization direction and partially reflected as light having a second polarization direction. By repeating such reflection and transmission many times inside the reflective polarizer, the efficiency of light utilization can be improved.

In one embodiment, the reflective polarizer may include a reflective layer R as the outermost layer on the wavelength conversion layer 10 side, as shown in FIG. By providing the reflective layer R, it is possible to further utilize the light that has returned to the outermost side of the reflective polarizer without being finally utilized, so that the efficiency of light utilization can be further improved. The reflective layer R typically exhibits a reflective function due to the multilayer structure of the polyester resin layer.

The overall thickness of the reflective polarizer can be appropriately set according to the purpose, the total number of layers contained in the reflective polarizer, and the like. The overall thickness of the reflective polarizer is preferably 10 μm to 150 μm.

In one embodiment, in the liquid crystal display device 100, the reflective polarizer 40 is arranged so as to transmit light in the polarization direction parallel to the transmission axis of the backside polarizing plate 32. That is, the reflective polarizer 40 is arranged so that its transmission axis is substantially parallel to the transmission axis direction of the back-side polarizing plate 32. With such a configuration, the light absorbed by the back side polarizing plate 32 can be reused, the utilization efficiency can be further improved, and the brightness can also be improved.

Reflective polarizers can typically be made by combining coextrusion and transverse stretching. Coextrusion can be done in any suitable manner. For example, it may be a feed block system or a multi-manifold system. For example, the material forming the A layer and the material forming the B layer are extruded in the feed block, and then multi-layered using a multiplier. Such a multi-layer device is known to those skilled in the art. Next, the obtained elongated multilayer laminate is typically stretched in a direction (TD) orthogonal to the transport direction. The material (for example, polyethylene naphthalate) constituting the layer A has an increased refractive index only in the stretching direction due to the lateral stretching, and as a result, exhibits birefringence. The refractive index of the material constituting the B layer (for example, copolyester of naphthalenedicarboxylic acid and terephthalic acid) does not increase in any direction by the transverse stretching. As a result, a reflective polarizer having a reflection axis in the stretching direction (TD) and a transmission axis in the transport direction (MD) can be obtained (TD corresponds to the x-axis direction of FIG. 3 and MD corresponds to the y-axis. Corresponds to the direction). The stretching operation can be performed using any suitable device.

As the reflective polarizer, for example, those described in JP-A-9-507308 can be used.

As the reflective polarizer, a commercially available product may be used as it is, or the commercially available product may be used after secondary processing (for example, stretching). Examples of commercially available products include the product name DBEF manufactured by 3M and the product name APF manufactured by 3M.

G. Wavelength Selective Absorption Layer The wavelength selective absorption layer 50 typically includes a resin as a matrix and a wavelength selective absorption material dispersed in the matrix.

Any suitable resin can be used as the resin constituting the matrix. Specifically, the resin may be a thermoplastic resin, a thermosetting resin, or an active energy ray-curable resin. Examples of the active energy ray-curable resin include an electron beam-curable resin, an ultraviolet-curable resin, and a visible light-curable resin. Specific examples of the resin include epoxy, (meth) acrylate (eg, methyl methacrylate, butyl acrylate), norbornene, polyethylene, poly (vinyl butyral), poly (vinyl acetate), polyurea, polyurethane, aminosilicone (AMS), etc. Polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, fluorinated silicones, vinyl and hydride substituted silicones, styrene-based polymers (eg, polystyrene, aminopolystyrene (APS), poly (eg, polystyrene, aminopolystyrene (APS), poly) Acrylic nitrile ethylene styrene) (AES)), polymers crosslinked with bifunctional monomers (eg divinylbenzene), polyester polymers (eg polyethylene terephthalates), cellulose polymers (eg triacetyl cellulose), vinyl chloride polymers , Amid-based polymer, imide-based polymer, vinyl alcohol-based polymer, epoxy-based polymer, silicone-based polymer, acrylic urethane-based polymer. These may be used alone or in combination (eg, blend, copolymer). These resins may be subjected to treatments such as stretching, heating, and pressurization after forming the film. A thermosetting resin or an ultraviolet curable resin is preferable.

The wavelength selective absorption material is as described in Section B-1-2 above with respect to the wavelength selective absorption pressure-sensitive adhesive layer.

The content of the wavelength selective absorption material in the wavelength selective absorption layer (total content when two or more kinds are used) is preferably 0.01 part by weight with respect to 100 parts by weight of the solid content of the matrix material (resin). It is ~ 100 parts by weight, more preferably 0.01 part by weight to 50 parts by weight, and further preferably 0.1 part by weight to 10 parts by weight. Within such a range, both high brightness and high color gamut (high color rendering properties) can be achieved at the same time.

The wavelength selective absorption layer can be formed, for example, by applying a liquid composition containing a matrix material (resin), a wavelength selective absorption material, and if necessary, an additive. For example, the wavelength selective absorption layer is a liquid composition comprising a matrix material, a wavelength selective absorption material, and optionally additives, a solvent, and a polymerization initiator applied to any suitable support, followed by drying and / or. It can be formed by curing. The solvent and polymerization initiator can be appropriately set depending on the type of matrix material (resin) used. As the coating method, any appropriate coating method can be used. Specific examples include curtain coating method, dip coating method, spin coating method, print coating method, spray coating method, slot coating method, roll coating method, slide coating method, blade coating method, gravure coating method, and wire bar method. Be done. Curing conditions can be appropriately set according to the type of matrix material (resin) used, the composition of the composition, and the like.

The wavelength selective absorption layer formed on the support can be transferred to other components of the liquid crystal display device (for example, a reflective polarizer, a retardation layer).

The wavelength selective absorption layer may be a single layer or may have a laminated structure. When the wavelength selective absorption layers have a laminated structure, each layer may typically contain wavelength selective absorption materials having different absorption maximum wavelengths.

The thickness of the wavelength selective absorption layer (in the case of having a laminated structure, the total thickness thereof) is preferably 1 μm to 500 μm, and more preferably 100 μm to 400 μm. When the thickness of the wavelength selective absorption layer is in such a range, the absorption efficiency and durability of light of a specific wavelength can be excellent. When the wavelength selective absorption layer has a laminated structure, the thickness of each layer is preferably 1 μm to 300 μm, and more preferably 10 μm to 250 μm.

The wavelength selective absorption layer preferably has a barrier function against oxygen and / or water vapor. As used herein, the term "having a barrier function" means controlling the amount of oxygen and / or water vapor that penetrates the wavelength selective absorption layer to substantially block the wavelength selective absorption material from them. The water vapor transmittance (moisture permeability) of the wavelength selective absorption layer in terms of thickness of 50 μm is preferably 100 g / m ² · day or less, and more preferably 80 g / m ² · day or less. By appropriately selecting the matrix material (resin), the desired barrier function can be obtained.

In one embodiment, the wavelength selective absorption layer has an anti-blocking function. As described above, the wavelength selective absorption layer itself may have an anti-blocking function, and the anti-blocking layer may be formed on the surface of the wavelength selective absorption layer opposite to the reflective polarizer. Since the wavelength selective absorption layer has an anti-blocking function, not only excellent anti-blocking property is realized when the laminated optical film including the wavelength selective absorption layer is stored, but also scratches caused by the backlight unit in the liquid crystal display device. Can be suppressed (excellent scratch resistance can be achieved).

When the wavelength selective absorption layer itself is provided with the anti-blocking function, typically, fine particles having desired characteristics and the most frequent particle size are dispersed in the above matrix material (resin). The fine particles are preferably transparent. Examples of the material constituting such fine particles include metal oxides, glass, and resins. Specific examples include inorganic fine particles such as silica, alumina, titania, zirconia, and calcium oxide, and organic fine particles such as polymethylmethacrylate, polystyrene, polyurethane, acrylic resin, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate. , Silicone particles and the like. One type of fine particles may be used alone, or two or more types may be used in combination. It is preferably organic fine particles, and more preferably acrylic resin fine particles. This is because the refractive index is appropriate.

The most frequent particle size of the fine particles can be appropriately set according to the scratch resistance, anti-blocking property, haze, etc. desired for the anti-blocking layer. The most frequent particle size of the fine particles is, for example, within ± 50% of the thickness of the anti-blocking layer. In the present specification, the "most frequent particle size" means a particle size indicating the maximum value of the particle distribution, and a flow type particle image analyzer (manufactured by Sysmex, product name "FPTA-3000S") is used. It is obtained by measuring under predetermined conditions (Sheath solution: ethyl acetate, measurement mode: HPF measurement, measurement method: total count). As the measurement sample, a dispersion in which the particles are diluted with ethyl acetate to 1.0% by weight and uniformly dispersed using an ultrasonic cleaner can be used.

The content of the fine particles in the wavelength selective absorption layer is preferably 0.05 parts by weight to 1.0 part by weight, more preferably 0.1 parts by weight, based on 100 parts by weight of the solid content of the matrix material (resin). It is ~ 0.5 part by weight, more preferably 0.1 part by weight to 0.2 part by weight. If the content of the fine particles is too low, the scratch resistance or anti-blocking property may be insufficient. If the content of the fine particles is too large, the haze of the anti-blocking layer becomes high, and the visibility of the liquid crystal display device may be insufficient.

When forming an anti-blocking layer, the anti-blocking layer typically contains a resin as a matrix and fine particles dispersed in the matrix. As the matrix material (resin), the same material as the matrix material (resin) of the wavelength selective absorption layer can be used. As the fine particles, the same fine particles as those in the case of imparting an anti-blocking function to the wavelength selective absorption layer itself can be used. The anti-blocking layer can be formed by the same method as the method for forming the wavelength selective absorption layer described above. The anti-blocking layer may further contain any suitable additive depending on the purpose. Specific examples of the additive include a reactive diluent, a plasticizer, a surfactant, an antioxidant, an ultraviolet absorber, a leveling agent, a thixotropy agent, and an antistatic agent. The number, type, combination, amount of additive, etc. of the additive can be appropriately set according to the purpose.

The thickness of the anti-blocking layer is preferably 0.5 μm to 2.0 μm, more preferably 0.8 μm to 1.5 μm. With such a thickness, good scratch resistance and anti-blocking property can be ensured without adversely affecting the optical characteristics desired for the liquid crystal display device.

Details of the structure, material, forming method, etc. of the anti-blocking layer are described in, for example, JP-A-2015-115171, JP-A-2015-141674, JP-A-2015-12870, and JP-A-2015-005272. Has been done. These statements are incorporated herein by reference.

Regardless of whether the wavelength selective absorption layer itself is provided with the anti-blocking function or the anti-blocking layer is formed, the surface on the liquid crystal cell side (the surface opposite to the reflective polarizer) is representative. It can be an uneven surface. The uneven surface may be a fine uneven surface or a surface having a flat portion and a raised portion. In one embodiment, the arithmetic mean roughness Ra of the surface is preferably 20 nm or more, more preferably 20 nm to 50 nm.

H. Phase Difference Layer The phase difference layer 60 may have any suitable optical and / or mechanical properties depending on the intended purpose.

The retardation layer typically shows a relationship in which the refractive index characteristic is nx> ny ≧ nz. The retardation layer can function as a λ / 4 plate in one embodiment. In this case, the in-plane retardation Re (550) of the retardation layer is preferably 100 nm to 200 nm, more preferably 110 nm to 180 nm, and even more preferably 120 nm to 160 nm. Here, "ny = nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny <nz may be satisfied as long as the effect of the present invention is not impaired.

The Nz coefficient of the retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3. ..

The retardation layer typically has a slow axis as a result of having the refractive index characteristics as described above. In one embodiment, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer of the backside polarizing plate is preferably 40 ° to 50 °, more preferably 42 ° to 48 °. Yes, more preferably about 45 °.

The retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, or may exhibit a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It is also possible to exhibit a flat wavelength dispersion characteristic in which the phase difference value hardly changes depending on the wavelength of the measurement light. In one embodiment, the retardation layer exhibits inverse dispersion wavelength characteristics. In this case, the Re (450) / Re (550) of the retardation layer is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less.

In the retardation layer, the absolute value of the photoelastic coefficient is preferably 2 × 10 ^-11 m ² / N or less, more preferably 2.0 × 10 ^-13 m ² / N to 1.5 ^{× 10 -11} m ² /. N, more preferably includes a resin of ^{1.0 × 10 -12 m 2 /N~1.2×10 -11} m 2 / N. When the absolute value of the photoelastic coefficient is in such a range, the phase difference change is unlikely to occur when a shrinkage stress during heating occurs. As a result, thermal unevenness of the obtained liquid crystal display device can be satisfactorily prevented.

The retardation layer may be composed of a resin film (typically a stretched film), or may be an orientation-solidified layer of a liquid crystal compound.

As the resin film, any suitable resin film that can satisfy the above characteristics can be used. Typical examples of such resins are cyclic olefin resins, polycarbonate resins, cellulose resins, polyester resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylics. Examples include based resins. When the retardation layer is composed of a resin film exhibiting inverse dispersion wavelength characteristics, a polycarbonate resin can be preferably used. The retardation layer can be obtained by stretching the resin film under any suitable stretching method and stretching conditions according to the desired properties (for example, refractive index characteristics, in-plane retardation, Nz coefficient).

Examples of the liquid crystal compound include a liquid crystal compound (nematic liquid crystal) in which the liquid crystal phase is a nematic phase. As such a liquid crystal compound, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal expression mechanism of the liquid crystal compound may be either lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination. When the liquid crystal compound is a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer and a crosslinkable monomer. This is because the orientation state of the liquid crystal monomer can be fixed by polymerizing or cross-linking (that is, curing) the liquid crystal monomer. After the liquid crystal monomers are oriented, for example, if the liquid crystal monomers are polymerized or crosslinked with each other, the oriented state can be fixed. Here, the polymer is formed by polymerization, and the three-dimensional network structure is formed by cross-linking, but these are non-liquid crystal. Therefore, the formed retardation layer does not undergo a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to a liquid crystal compound, for example. As a result, the retardation layer becomes an extremely stable retardation layer that is not affected by temperature changes. In addition, in this specification, the "alignment solidification layer" means a layer in which a liquid crystal compound is oriented in a predetermined direction in a layer, and the orientation state is fixed. The "oriented solidified layer" is a concept that also includes the above-mentioned oriented hardened layer. Specific examples of the liquid crystal compound and details of the method for forming the oriented solidified layer are described in JP-A-2006-163343. The description of this publication is incorporated herein by reference.

The thickness of the retardation layer can be set so that a desired in-plane retardation can be obtained as a λ / 4 plate. When the retardation layer is made of a resin film, its thickness is preferably 60 μm or less, preferably 30 μm to 55 μm. When the retardation layer is composed of an orientation-solidified layer of a liquid crystal compound, the thickness thereof is preferably 0.5 μm to 7 μm, more preferably 1 μm to 5 μm.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method of each characteristic in the examples is as follows. Unless otherwise specified, "parts" and "%" in the examples are based on weight.

(1) Front luminance The measurement was carried out using a color luminance meter (SR-UL1 manufactured by Topcon Techno House Co., Ltd.).
(2) Color gamut (color rendering)
A single color of red, green, and blue was displayed on the liquid crystal display device, and the chromaticity (x, y) of each displayed color was measured by the color luminance meter of (1) above. The area of the triangle obtained by connecting the three points of the obtained red, green, and blue coordinates (x, y) was calculated, and the ratio to the area of the specified color gamut (triangle) of DCI-P3 was calculated.
(3) Scratch resistance Using the product name "10-series pen test" manufactured by MTM, attach steel wool (manufactured by Bonstar Sales Co., Ltd., product name "# 0000") to a 25 mmφ jig with double-sided tape. A jig was placed on the sample surface under a load of 300 g, and the state of the scratch was visually confirmed after 10 reciprocating tests. It was evaluated according to the following evaluation criteria.
⊚: No scratches were confirmed ○: 1 or more and less than 10 scratches were confirmed ×: 10 or more scratches were confirmed

<Example 1>
(Manufacturing a polarizing plate having a thin polarizer)
First, a laminate in which a 9 μm-thick PVA layer was formed on an amorphous PET substrate was integrally stretched. Specifically, the laminated body is subjected to aerial auxiliary stretching at a stretching temperature of 130 ° C. to prepare a stretched laminated body, then the stretched laminated body is subjected to dyeing to prepare a colored laminated body, and further, a colored laminated body is obtained. It was subjected to boric acid water stretching at a stretching temperature of 65 ° C. (total stretching ratio 5.94 times). In this way, an optical film laminate containing an amorphous PET substrate and a 4 μm-thick PVA layer (polarizer) was produced. Further, a polyvinyl alcohol-based adhesive was applied to the surface of the polarizer of the optical film laminate, and a saponified 40 μm-thick acrylic resin film was attached to the coated surface. Next, the amorphous PET substrate was peeled off to prepare a polarizing plate having a structure of a thin polarizer / protective layer (acrylic resin film).

(Preparation of adhesive composition)
1. 1. Preparation of Acrylic Polymer In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, a monomer mixture containing 82 parts of butyl acrylate, 15 parts of benzyl acrylate, and 3 parts of 4-hydroxybutyl acrylate was placed. I prepared it. Further, 0.1 part of 2,2'-azobisisobutyronitrile was charged together with ethyl acetate as a polymerization initiator with respect to 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring. After substituting with nitrogen, the liquid temperature in the flask was maintained at around 60 ° C. and the polymerization reaction was carried out for 7 hours. Then, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic polymer having a weight average molecular weight of 1 million adjusted to a solid content concentration of 30%.
2. Preparation of Adhesive Composition To 100 parts of the solid content of the acrylic polymer solution obtained above, 0.002 part of lithium bis (trifluoromethanesulfonyl) imide (manufactured by Nippon Carlit Co., Ltd.) was added, and further, trimethylol was added. Propanixylylene diisocyanate (manufactured by Mitsui Chemicals, Inc .: Takenate D110N) 0.1 part, dibenzoyl peroxide 0.3 parts, γ-glycidoxypropylmethoxysilane (manufactured by Shinetsu Chemical Industries, Ltd .: KBM-403) 075 parts, 0.5 part of Cyril SAT10 (number average molecular weight 4000) manufactured by Kaneka Co., Ltd., and porphyrin dye (trade name FDG-007 manufactured by Yamada Chemical Industry Co., Ltd .: having a maximum absorption wavelength at a wavelength of 595 nm) 0.25 To prepare an acrylic pressure-sensitive adhesive solution.

(Polarizing plate with wavelength selective absorption adhesive layer: Fabrication of viewing side polarizing plate)
The wavelength selective absorption pressure-sensitive adhesive composition obtained above is uniformly applied to the surface of a release base material (MRF38CK manufactured by Mitsubishi Resin Co., Ltd.) of a polyethylene terephthalate film treated with a silicone-based release agent with an applicator, and 155. A wavelength selective absorption pressure-sensitive adhesive layer having a thickness of 20 μm was formed by drying in an air circulation type constant temperature oven at ° C. for 2 minutes. This wavelength selective absorption pressure-sensitive adhesive layer was transferred to the surface of the polarizer of the above-mentioned polarizing plate to prepare a polarizing plate with a wavelength selective absorption pressure-sensitive adhesive layer.

(Optical member: Fabrication of backside polarizing plate)
An adhesive layer was formed on the release base material in the same manner as above except that the porphyrin-based dye was not blended. This pressure-sensitive adhesive layer was transferred to the polarizer surface of the same polarizing plate as described above to prepare a polarizing plate with a pressure-sensitive adhesive layer. Further, a reflective polarizing element is attached to the surface of the protective layer of the polarizing plate with an adhesive layer via a normal acrylic pressure-sensitive adhesive (thickness 23 μm) to form a structure of the pressure-sensitive adhesive layer / polarizing plate / reflective polarizer. An optical member to have was produced. As the reflective polarizer, a reflective polarizer taken out from the backlight unit of a liquid crystal TV (43UF7710) manufactured by LG Electronics Co., Ltd., from which the diffusion layers provided on both sides were removed, was used.

(Manufacturing of liquid crystal display device)
A liquid crystal panel (a liquid crystal panel including an IPS mode liquid crystal cell) was taken out from a liquid crystal TV (43UF7710) manufactured by LG Electronics, and all optical films and the like on both sides of the liquid crystal cell were further removed. The removed surface (the surface of the substrate) was washed, and the obtained liquid crystal cell was used. The above-mentioned polarizing plate with a wavelength selective absorption adhesive layer was attached to the visible surface of the liquid crystal cell via the wavelength selective absorption adhesive layer. Further, the above optical member was attached to the back surface side of the liquid crystal cell via the pressure-sensitive adhesive layer. In this way, a liquid crystal panel in IPS mode was produced. A backlight unit was incorporated into this liquid crystal panel to produce a liquid crystal display device having the configuration shown in FIG. The obtained liquid crystal display device was subjected to the evaluations (1) to (3) above. The results are shown in Table 1.

<Comparative example 1>
A liquid crystal display device was produced in the same manner as in Example 1 except that the reflective polarizer was not arranged. The obtained liquid crystal display device was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Comparative example 2>
Examples except that the visible side pressure-sensitive adhesive layer was formed by using a normal acrylic pressure-sensitive adhesive (the same pressure-sensitive adhesive used for the back-side pressure-sensitive adhesive layer of Example 1) instead of the wavelength-selective absorption pressure-sensitive adhesive layer. A liquid crystal display device was produced in the same manner as in 1. The obtained liquid crystal display device was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Example 2>
The visible side adhesive layer was formed by using a normal acrylic pressure-sensitive adhesive (the same pressure-sensitive adhesive used for the back-side pressure-sensitive adhesive layer of Example 1) instead of the wavelength-selective absorption pressure-sensitive adhesive layer, and optics. A liquid crystal display device having the configuration shown in FIG. 2 was produced in the same manner as in Example 1 except that the wavelength selective absorption layer was provided on the back surface side of the reflective polarizer of the member. The obtained liquid crystal display device was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
The wavelength selective absorption layer was formed as follows. A cycloolefin (norbornene) resin film (manufactured by Zeon Corporation, product name "Zeonoa ZF16", thickness 40 μm, in-plane retardation Re (550) = 140 nm) was used as a support. On the other hand, the wavelength selection by blending 0.75 weight of the wavelength selective absorbing dye used in Example 1 with 100 parts by weight of an ultraviolet curable resin (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat # 300") A resin composition for forming an absorption layer was prepared. This resin composition was applied to a support and irradiated with ultraviolet rays at an exposure amount of 230 mJ / cm ² to form a wavelength selective absorption layer. The thickness of the obtained wavelength selective absorption layer was 5 μm. In this way, a laminated body of the wavelength selective absorption layer / support (λ / 4 plate) was produced. The support of the obtained laminate was attached to the reflective polarizer of the optical member.

<Example 3>
A liquid crystal display device was produced in the same manner as in Example 2 except that an anti-blocking layer was provided on the back side of the wavelength selective absorption layer. The obtained liquid crystal display device was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
The anti-blocking layer was formed as follows. A cycloolefin (norbornene) resin film (manufactured by Zeon Corporation, product name "Zeonoa ZF16", thickness 40 μm) was used as a support. On the other hand, for 100 parts by weight of ultraviolet curable resin (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat # 300"), acrylic resin fine particles (manufactured by Sekisui Kasei Co., Ltd., trade name "XX-131-AA", most A resin composition for forming an anti-blocking layer was prepared by blending 5 parts by weight (frequent particle diameter 3 μm). This resin composition was applied to a support and irradiated with ultraviolet rays at an exposure amount of 230 mJ / cm ² to form an anti-blocking layer. The thickness of the obtained anti-blocking layer was 5 μm. In this way, an anti-blocking layer / support laminate was produced. From the obtained laminate, the anti-blocking layer was transferred to the wavelength selective absorption layer via an acrylic pressure-sensitive adhesive.

<Evaluation>
As is clear from Table 1, the liquid crystal display device according to the embodiment of the present invention is excellent in front luminance and color gamut (color rendering property) in a well-balanced manner. Further, in the liquid crystal display device of Example 3, the scratch resistance is remarkably improved by imparting an anti-blocking function to the wavelength selective absorption layer. Furthermore, it has been confirmed that the liquid crystal display device of the example can be manufactured at a very low cost because it does not use an expensive material such as a quantum dot and does not complicate the configuration of the device.

The liquid crystal display device of the present invention includes portable devices such as mobile information terminals (PDAs), mobile phones, clocks, digital cameras, and portable game machines, OA devices such as personal computer monitors, laptop computers, and copiers, video cameras, and liquid crystal televisions. Household electrical equipment such as microwave ovens, back monitors, car navigation system monitors, in-vehicle equipment such as car audio, exhibition equipment such as information monitors for commercial stores, security equipment such as monitoring monitors, nursing care monitors, medical care It can be used for various purposes such as nursing care / medical equipment such as monitors.

10 Liquid crystal cell 21 Wavelength selective absorption adhesive layer 22 Back side adhesive layer 23 Visible side adhesive layer 31 Visible side polarizing plate 32 Back side polarizing plate 40 Reflective polarizing element 50 Wavelength selective absorption layer 60 Phase difference layer 100 Liquid crystal display device 101 Liquid crystal display device

Claims (5)

LCD cell and
The visible side adhesive layer and the visible side polarizing plate arranged in order from the liquid crystal cell side on the visible side of the liquid crystal cell,
A back surface adhesive layer, a back surface polarizing plate, and a reflective polarizing element arranged in order from the liquid crystal cell side on the back surface side of the liquid crystal cell.
With
A wavelength selective absorption layer is provided on the side opposite to the backside polarizing plate of the reflective polarizer.
A retardation layer having an in-plane retardation Re (550) of 100 nm to 200 nm is further provided between the reflective polarizer and the wavelength selective absorption layer.
The wavelength selective absorption layer is formed directly on the retardation layer, and the wavelength selective absorption layer is formed directly on the retardation layer.
The wavelength selective absorption layer comprises a wavelength selective absorption material having an absorption maximum wavelength in a wavelength band in the range of 570 nm to 610 nm.
Liquid crystal display device. The liquid crystal display device according to claim 1, wherein the wavelength selective absorption layer has an anti-blocking function. The liquid crystal display device according to claim 2, wherein the arithmetic average roughness Ra of the surface of the wavelength selective absorption layer opposite to the reflective polarizer is 20 nm or more. The liquid crystal display device according to any one of claims 1 to 3, wherein the angle formed by the absorption axis of the polarizing element of the backside polarizing plate and the slow axis of the retardation layer is 40 ° to 50 °. It has a wavelength selective absorption layer, a retardation layer, a reflective polarizer, a polarizing plate, and an adhesive layer in this order.
The wavelength selective absorption layer is formed directly on the retardation layer, and the wavelength selective absorption layer is formed directly on the retardation layer.
The in-plane retardation Re (550) of the retardation layer is 100 nm to 200 nm.
The wavelength selective absorption layer contains a wavelength selective absorption material having an absorption maximum wavelength in a wavelength band in the range of 570 nm to 610 nm.
It is attached to the back side of the liquid crystal cell via the pressure-sensitive adhesive layer.
Optical member.

Images