CN108292004B - Elongated optical laminated body and image display device - Google Patents

Abstract

The present invention provides an elongated optical layered body capable of reducing variation in display characteristics of each product when it is cut to a predetermined size and applied to an image display device. The optical laminated body of the present invention is elongated, and it has a polarizing plate including a polarizer and a protective layer on at least one side of the polarizer, a first retardation layer, a second retardation layer, a conductive layer, and a conductive layer. Adhesively laminated substrates. The in-plane retardation Re(550) of the substrate is 3nm to 6nm, the retardation variation in the width direction is 10% to 30%, and the variation in the slow axis direction in the width direction is 1° to 5°. The in-plane retardation Re(550) of the first retardation layer is 220nm～250nm, the angle formed by the slow axis of the first retardation layer and the absorption axis of the polarizer is 10°～20°, the second retardation layer The in-plane retardation Re(550) is 110nm-125nm, and the angle formed by the slow axis of the second retardation layer and the absorption axis of the polarizer is 65°-85°.

Description

Elongated optical laminated body and image display device

technical field

The present invention relates to an elongated optical layered body and an image display device using the elongated optical layered body.

Background technique

In recent years, with the spread of thin displays, displays (organic EL display devices) equipped with organic EL panels have been proposed. Since the organic EL panel has a highly reflective metal layer, problems such as reflection of external light or reflection of the background are likely to occur. Therefore, it is known to prevent these problems by providing a circular polarizing plate on the visual confirmation side. On the other hand, there is increasing demand for so-called built-in touch panel type input display devices in which a touch sensor is incorporated between a display unit (for example, an organic EL unit) and a polarizing plate. The input display device configured in this way can provide the user with a natural sense of input operation because the distance between the image display unit and the touch sensor is short.

For polarizers (or circular polarizers) for input display devices with built-in touch panels, from the viewpoint of thinning, preventing quality deviation, and improving manufacturing efficiency, polarizers (or circular polarizers) and conductive polarizers for touch sensors are being studied. The integration of flexible films. For example, an attempt has been made to bond a long polarizing plate (or a circular polarizing plate) and a long conductive film by so-called roll-to-roll. However, the polarizing plate integrated with the conductive film by roll-to-roll has a problem that the characteristic variation in the width direction is large. As a result, when such a polarizing plate integrated with a conductive film is cut into a predetermined size and applied to an image display device, there may be unacceptable variations in the display characteristics of each product.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2003-311239

Patent Document 2: Japanese Patent Laid-Open No. 2002-372622

Patent Document 3: Japanese Patent No. 3325560

Patent Document 4: Japanese Patent Laid-Open No. 2003-036143

Contents of the invention

The problem to be solved by the invention

The present invention was made to solve the above conventional problems, and its main object is to provide an elongated optical laminate that can be cut into a predetermined size and applied to an image display device. The variation in the display characteristics of each product is reduced.

means of solving problems

The optical laminated body of the present invention is elongated, and it has a polarizing plate including a polarizer and a protective layer on at least one side of the polarizer, a first retardation layer, a second retardation layer, a conductive layer, and the A base material in which conductive layers are laminated in close contact. The in-plane retardation Re(550) of the substrate is 3nm to 6nm, the deviation of the retardation of the substrate in the width direction is 10% to 30%, and the deviation of the slow axis direction of the substrate in the width direction is 1°～5°. In the optical laminate of the present invention, the in-plane retardation Re(550) of the first retardation layer is 220 nm to 250 nm, and the angle formed by the slow axis of the first retardation layer and the absorption axis of the polarizer is 10°～20°; the in-plane retardation Re(550) of the second retardation layer is 110nm～125nm, and the angle formed by the slow axis of the second retardation layer and the absorption axis of the polarizer is 65°～ 85°.

In one Embodiment, the said optical laminated body is roll shape.

In one Embodiment, the width of the said optical laminated body is 500 mm or more.

In one embodiment, the first retardation layer and the second retardation layer are formed of a cyclic olefin-based resin film. According to another embodiment, the above-mentioned first retardation layer and the above-mentioned second retardation layer are alignment solidified layers of liquid crystal compounds.

According to another aspect of the present invention, an image display device is provided. This image display device includes the above-mentioned optical laminate cut to a predetermined size.

Invention effect

According to the present invention, optical compensation is performed by combining specific two retardation layers as the retardation layer for the elongated optical laminated body having the polarizer, the retardation layer, and the conductive layer for the touch sensor. The deviation of the characteristics of the width direction of the optical laminate caused by the phase difference of the substrate having the conductive layer and the deviation of the width direction of the phase difference, etc., but when the optical laminate is cut into a predetermined size and applied to an image display device In some cases, it is possible to reduce the variation in the display characteristics of each product.

Description of drawings

FIG. 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention.

FIG. 2 is a schematic plan view illustrating the overall configuration of a diagonal stretching device used in Reference Example 4. FIG.

FIG. 3 is a schematic plan view of main parts for explaining a connection mechanism for changing the distance between clamps in the oblique stretching device of FIG. 2 , showing a state in which the distance between clamps is the smallest.

FIG. 4 is a schematic plan view of main parts for explaining a connection mechanism for changing the distance between clamps in the oblique stretching device of FIG. 2 , showing a state where the distance between clamps is the largest.

FIG. 5 is a schematic diagram illustrating an embodiment of oblique stretching used in Reference Example 4. FIG.

Fig. 6 is a diagram showing the relationship between each region of the oblique stretching device and the distance between clips during the oblique stretching shown in Fig. 5 .

Detailed ways

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)

Definitions of terms and symbols used in this specification are as follows.

(1) Refractive index (nx, ny, nz)

"nx" is the refractive index in the direction in which the in-plane refractive index becomes the largest (that is, the slow axis direction), "ny" is the refractive index in the in-plane direction perpendicular to the slow axis (that is, the fast axis direction), and "nz" is the refractive index in the thickness direction.

(2) In-plane retardation (Re)

"Re(λ)" is an in-plane retardation measured with light having a wavelength of λnm at 23°C. For example, "Re(550)" is an in-plane retardation measured with light having a wavelength of 550 nm at 23°C. When the thickness of the layer (thin film) is d (nm), Re(λ) can be obtained by the formula Re(λ)=(nx-ny)×d.

(3) Phase difference in the thickness direction (Rth)

"Rth(λ)" is the retardation in the thickness direction measured with light having a wavelength of λnm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23°C. When the thickness of the layer (thin film) is set to d (nm), Rth(λ) can be obtained by the formula Rth(λ)=(nx-nz)×d.

(4) Nz coefficient

The Nz coefficient can be obtained by Nz=Rth/Re.

A. Overall configuration of the optical laminate

FIG. 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminate 100 of this embodiment has the polarizing plate 10, the 1st retardation layer 20, the 2nd retardation layer 30, the conductive layer 41, and the base material 42 in this order. The polarizer 10 includes a polarizer 11 , a first protective layer 12 arranged on one side of the polarizer 11 , and a second protective layer 13 arranged on the other side of the polarizer 11 . Depending on purposes, one of the first protective layer 12 and the second protective layer 13 may also be omitted. For example, when the first retardation layer 20 can also function as a protective layer of the polarizer 11, the second protective layer 13 can be omitted. The substrate 42 is laminated closely with the conductive layer 41 . In this specification, "adhesive lamination" means that two layers are directly and adhesively laminated without interposing an adhesive layer (for example, an adhesive layer, an adhesive layer). Typically, the conductive layer 41 and the substrate 42 can be introduced into the optical laminate 100 as a laminate of the substrate 42 and the conductive layer 41 . In addition, the ratio of the thickness of each layer in the drawings is different from the actual one for easy observation.

Although it is not clear from the drawings, the optical layered body according to the embodiment of the present invention is elongated. Therefore, the constituent elements (for example, a polarizing plate, a retardation layer, a base material) of an optical laminated body are also elongated. In one embodiment, the optical laminate is wound into a roll. In the present specification, "elongated" refers to an elongated shape whose length is sufficiently long relative to the width, and includes, for example, an elongated shape whose length is 10 times or more, preferably 20 times or more, relative to the width. Therefore, the optical laminate 100 can be produced, for example, by combining the elongated polarizing plate 10, the elongated retardation film constituting the first retardation layer 20, and the elongated retardation film constituting the second retardation layer 30. And the long conductive film (the laminated body of the conductive layer 41 and the base material) is laminated by roll-to-roll. In addition, in this specification, "roll-to-roll" means to make a mutual longitudinal direction coincide and bond while conveying a roll-shaped film.

As described above, the optical laminate 100 has two retardation layers (the first retardation layer 20 and the second retardation layer 30 ). The first retardation layer 20 has a slow axis. The angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is 10°-20°, preferably 13°-17°, more preferably about 15°. The first retardation layer preferably has a refractive index characteristic showing the relationship of nx>ny≧nz. The in-plane retardation Re(550) of the first retardation layer is 220 nm to 250 nm, preferably 230 nm to 240 nm. The second retardation layer 30 also has a slow axis. The angle formed by the slow axis of the second retardation layer 30 and the absorption axis of the polarizer 11 is 65°-85°, preferably 72°-78°, more preferably about 75°. The second retardation layer preferably has a refractive index characteristic showing the relationship of nx>ny≧nz. The in-plane retardation Re(550) of the second retardation layer is 110 nm to 125 nm, preferably 115 nm to 120 nm. As described above, the in-plane retardation of the first retardation layer is set slightly smaller than that of the so-called λ/2 plate, and the in-plane retardation of the second retardation layer is set slightly smaller than that of the so-called λ/4 plate. By setting in this way, very excellent reflectance and reflection color tone can be realized when each retardation layer is constituted using the following materials. According to the present invention, optical compensation is performed by combining two retardation layers having the characteristics as described above, although there is a deviation in the width direction of the optical laminate due to the retardation of the base material and the deviation in the width direction of the retardation, etc. However, when the optical laminate is cut into a predetermined size and applied to an image display device, the variation in display characteristics of each product can be reduced. Such an effect cannot be obtained by a single retardation layer having characteristics optically equivalent to the above-mentioned combination of the two retardation layers. That is, this effect is obtained by combining the above-mentioned two retardation layers to produce an optical laminate, cutting the optical laminate to a predetermined size and applying it to an image display device, and it is an unexpectedly excellent effect.

The in-plane retardation Re(550) of the substrate 42 is 3 nm to 6 nm, preferably 4 nm to 5 nm. The deviation of the phase difference in the width direction of the substrate 42 is 10% to 30%, preferably 15% to 25%. The deviation of the slow axis direction of the substrate 42 in the width direction is 1° to 5°, preferably 1° to 3°. According to the present invention, even when the base material has a phase difference and the phase difference and the slow axis direction have deviations in the width direction, resulting in deviations in the characteristics of the width direction of the optical laminate, by making the specified two Combining two retardation layers to perform optical compensation, even when the optical laminate is cut into a predetermined size and applied to an image display device, the deviation of the display characteristics of each product can be reduced. In addition, in this specification, the "deviation in phase difference" means the maximum value of the deviation from the set phase difference, and the "deviation in the direction of the slow axis" means the maximum value of the deviation in the direction of the slow axis from the setting.

The width of the optical laminate is preferably 500 mm or more, more preferably 800 mm or more. The upper limit of the width is, for example, 1500 mm. The wider the width, the larger the variations in the properties of the optical layered body in the width direction due to the retardation of the above-mentioned base materials, etc., so that the effect of the present invention can be significantly exhibited.

In one embodiment, the first retardation layer 20 and the second retardation layer 30 are respectively made of resin films. As for another embodiment, the first retardation layer 20 and the second retardation layer 30 may respectively be alignment solidified layers of liquid crystal compounds. In addition, the details of the resin film are described in Items C-2 and D-2, and the details of the aligned solidified layer of the liquid crystal compound are described in Items C-3 and D-3.

In addition to the close lamination of the conductive layer 41 and the base material 42, each layer constituting the optical laminate may be laminated via any appropriate adhesive layer (adhesive layer or adhesive layer: not shown), or Adhesive lamination is carried out similarly to the case of the conductive layer 41 and the base material 42 .

The dimensional change rate of the optical laminate is preferably 1% or less, more preferably 0.95% or less. The smaller the dimensional change rate of the optical layered body, the better. The lower limit of the dimensional change rate of the optical laminated body is, for example, 0.01%. When the dimensional change rate of the optical laminate is within such a range, the generation of cracks in the conductive layer under high temperature and high humidity can be significantly suppressed.

The total thickness of the optical layered body is preferably 220 μm or less, more preferably 80 μm to 190 μm. When the first retardation layer 20 and the second retardation layer 30 are alignment-cured layers of liquid crystal compounds, the total thickness of the optical laminate is preferably 175 μm or less, more preferably 80 μm to 140 μm.

Hereinafter, each layer, an optical film, and an adhesive agent which comprise an optical laminated body are demonstrated in detail.

B. Polarizer

B-1. Polarizer

As the polarizer 11, any appropriate polarizer can be used. For example, the resin film forming the polarizer may be a single-layer resin film, or may be a laminate of two or more layers.

Specific examples of polarizers composed of single-layer resin films include polyvinyl alcohol (PVA)-based films, partially formalized PVA-based films, ethylene-vinyl acetate copolymer-based partially saponified films, and the like. Polyene-based oriented films such as dehydration-treated products of PVA and dehydrochloric acid-treated products of polyvinyl chloride, etc. . From the viewpoint of excellent optical properties, it is preferable to use a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching it.

The above-mentioned dyeing with iodine can be performed, for example, by immersing a PVA-based film in an iodine aqueous solution. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or stretching may be performed while dyeing. In addition, dyeing may be performed after stretching. Swelling treatment, crosslinking treatment, cleaning treatment, drying treatment, etc. may be performed on the PVA-based film as needed. For example, before dyeing, immersing the PVA-based film in water and washing it with water not only removes stains and anti-blocking agents on the surface of the PVA-based film, but also swells the PVA-based film to prevent uneven dyeing.

Specific examples of polarizers obtained using a laminate include a laminate using 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 formed on a layer coated with a resin base material. A polarizer obtained by laminating the PVA-based resin layer of the resin substrate. A polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer coated and formed on the resin base material can be produced, for example, by applying a PVA-based resin solution to a resin base material, drying it, and A PVA-based resin layer is formed on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer into a polarizer. In this embodiment, stretching typically includes immersing and stretching the laminate in an aqueous solution of boric acid. Furthermore, the stretching may further include, if necessary, stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in a boric acid aqueous solution. The obtained resin substrate/polarizer laminate can be used as it is (that is, the resin substrate can be used as a protective layer of the polarizer), or the resin substrate can be peeled off from the resin substrate/polarizer laminate, and Any appropriate protective layer according to the purpose is laminated on the peeling surface and used. The details of such a method of manufacturing a polarizer are described in, for example, JP-A-2012-73580. The entire description content of this publication is taken in this specification as a reference.

The thickness of the polarizer is preferably 18 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 12 μm, particularly preferably 5 μm to 12 μm.

The boric acid content of the polarizer is preferably 18% by weight or more, more preferably 18% by weight to 25% by weight. In the case where the boric acid content of the polarizer is within this range, the ease of adjusting curl during lamination can be well maintained, and curl during heating can be well suppressed, while improving appearance durability. The boric acid content can be calculated as the amount of boric acid contained in the polarizer per unit weight by using the following formula according to the neutralization method, for example.

The iodine content of the polarizer is preferably 2.1% by weight or more, more preferably 2.1% by weight to 3.5% by weight. In the case where the iodine content of the polarizer is within this range, the ease of adjusting curl during lamination can be well maintained, and curl during heating can be well suppressed, and at the same time, the stability during heating can be improved due to the synergistic effect with the above-mentioned boric acid content. Appearance durability. In this specification, "iodine content" means the quantity of all iodine contained in a polarizer (PVA-type resin film). More specifically, when iodine exists in the form of iodide ion (I ^- ), iodine molecule (I ₂ ), polyiodide ion (I ₃ ^- , I ₅ ^- ) in the polarizer, the iodine content in this specification means The amount of iodine contained in all of these forms. The iodine content can be calculated by the calibration curve method of fluorescent X-ray analysis, for example. In addition, polyiodide ions exist in the state of forming a PVA-iodine complex in the polarizer. By forming such a complex, absorption dichroism can be exhibited in the wavelength range of visible light. Specifically, the complex of PVA and triiodide ions (PVA-I ₃ ^- ) has an absorption peak near 470nm, and the complex of PVA and pentaiodide ions (PVA-I ₅ ^- ) has an absorption peak near 600nm peak. As a result, polyiodide ions can absorb light in a wide range of visible light depending on their morphology. On the other hand, iodide ions (I ^- ) have an absorption peak around 230 nm and do not substantially participate in the absorption of visible light. Therefore, polyiodide ions existing in the state of a complex with PVA may mainly participate in the absorption performance of the polarizer.

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

B-2. First protective layer

The first protective layer 12 is formed of any suitable film that can be used as a protective layer of a polarizer. Specific examples of the material used as 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 resins, etc. Amine-based, polyethersulfone-based, polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based, acetate-based transparent resins, etc. In addition, thermosetting resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone, or ultraviolet curable resins are also mentioned. Moreover, glassy polymers, such as a siloxane type polymer, are also mentioned, for example. In addition, a polymer film described in JP-A-2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in a side chain can be used. For example, the resin composition which has the alternating copolymer which consists of isobutylene and N-methylmaleimide, and an acrylonitrile-styrene copolymer is mentioned. The polymer film may be, for example, an extruded product of the above-mentioned resin composition.

The optical laminated body of this invention is typically arrange|positioned at the visual confirmation side of an image display apparatus as follows, and the 1st protective layer 12 is typically arrange|positioned at the visual confirmation side. Therefore, surface treatments such as hard coat treatment, antireflection treatment, antisticking treatment, and antiglare treatment may be performed on the first protective layer 12 as necessary. And/or, if necessary, the first protective layer 12 may also be subjected to treatment to improve the visibility when visually confirmed through polarized sunglasses (typically imparting (ellipso)polarization function, imparting ultra-high retardation ). By performing such processing, even when the display screen is visually recognized through polarized lenses such as polarized sunglasses, excellent visibility can be realized. Therefore, the optical laminated body can also be suitably applied to the image display apparatus which can be used outdoors.

As for the thickness of the first protective layer, any appropriate thickness can be adopted as long as the difference between the desired thickness of the polarizing plate and the thickness of the second protective layer can be obtained. The thickness of the first protective layer is, for example, 10 μm to 50 μm, preferably 15 μm to 40 μm. In addition, when surface treatment is performed, the thickness of the first protective layer is a thickness including the thickness of the surface treatment layer.

B-3. Second protective layer

The second protective layer 13 is also formed of any appropriate film that can be used as a protective layer of a polarizer. The material constituting the main component of the thin film is as described for the first protective layer in the above item B-2. The second protective layer 13 is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane retardation Re(550) is 0 nm to 10 nm, and the retardation Rth(550) in the thickness direction is -10 nm to +10 nm.

The thickness of the second protective layer is, for example, 15 μm to 35 μm, preferably 20 μm to 30 μm. The difference between the thickness of the first protective layer and the thickness of the second protective layer is preferably 15 μm or less, more preferably 10 μm or less. When the difference in thickness is such a range, curling at the time of bonding can be suppressed favorably. The thickness of the first protective layer can be the same as that of the second protective layer, or the first protective layer can be thicker, and the second protective layer can also be thicker. Typically, the first protective layer is thicker than the second protective layer.

C. The first retardation layer

C-1. Characteristics of the first retardation layer

As described above, the first retardation layer 20 has a slow axis. The angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is preferably 10° to 20°, more preferably 13° to 17°, and even more preferably about 15°. In the case where the angle formed by the slow axis of the first retardation layer 20 and the absorption axis of the polarizer 11 is in such a range, the in-plane phase phase of the first retardation layer and the second retardation layer can be adjusted as follows. The difference is set to a specified range, and the slow axis of the second retardation layer is arranged at a specified angle with respect to the absorption axis of the polarizer, thereby obtaining very excellent circularly polarized light characteristics in a wide frequency band (resulting in very excellent anti- reflective properties) optical laminates.

The first retardation layer preferably has a refractive index characteristic showing the relationship of nx>ny≧nz. The in-plane retardation Re(550) of the first retardation layer is 220 nm to 250 nm, preferably 230 nm to 240 nm. In addition, 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 exist as long as the effect of the present invention is not impaired.

The Nz coefficient of the first retardation layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, particularly preferably 0.9 to 1.3. By satisfying such a relationship, when the obtained optical laminate is used for an image display device, a very excellent reflection color tone can be realized.

The first retardation layer may exhibit a reverse dispersion wavelength characteristic in which the phase difference value becomes larger according to the wavelength of the measurement light, or may exhibit a forward wavelength dispersion characteristic in which the phase difference value becomes smaller according to the wavelength of the measurement light, or It exhibits a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light. In one embodiment, the first retardation layer exhibits flat wavelength dispersion characteristics in which the retardation value hardly changes depending on the wavelength of the measurement light. In this case, Re(450)/Re(550) of the retardation layer is preferably 0.99 to 1.03, and Re(650)/Re(550) is preferably 0.98 to 1.02. By combining a first retardation layer exhibiting flat wavelength dispersion characteristics and having a predetermined in-plane retardation with a second retardation layer exhibiting flat wavelength dispersion characteristics and having a predetermined in-plane retardation at a predetermined slow axis angle. Using it, very excellent anti-reflection characteristics can be realized in a wide frequency band.

The absolute value of the photoelastic coefficient contained in the first retardation layer 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, still more preferably The resin is 1.0×10 ^-12 m ² /N to 1.2×10 ^-11 m ² /N. In the case where the absolute value of the photoelastic coefficient is within such a range, a phase difference change is less likely to occur when shrinkage stress during heating occurs. As a result, thermal unevenness of the obtained image display device can be prevented favorably.

The dimensional change rate of the first retardation layer is preferably 1% or less, more preferably 0.95% or less. The smaller the dimensional change rate of the first retardation layer, the better. The lower limit of the dimensional change rate of the first retardation layer is, for example, 0.01%. When the dimensional change rate of the first retardation layer is in such a range, the occurrence of cracks in the conductive layer under high temperature and high humidity can be significantly suppressed.

C-2. First retardation layer made of resin film

When the first retardation layer is made of a resin film, its thickness is preferably 60 μm or less, preferably 30 μm to 50 μm. When the thickness of the first retardation layer is within such a range, a desired in-plane retardation can be obtained.

The first retardation layer 20 can be composed of any appropriate resin film that can satisfy the characteristics described in the above item C-1. Representative examples of such resins include cyclic olefin-based resins, polycarbonate-based resins, cellulose-based resins, polyester-based resins, polyvinyl alcohol-based resins, polyamide-based resins, and polyimide-based resins. , Polyether resin, polystyrene resin, acrylic resin. When the first retardation layer is formed of a resin film showing flat wavelength characteristics, a cyclic olefin-based resin can be suitably used.

Cyclic olefin-based resins are collectively referred to as resins polymerized with cyclic olefins as polymerization units, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, etc. the resins described. Specific examples include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers (typically random copolymers) of cyclic olefins and α-olefins such as ethylene and propylene. substances) and grafted modified products obtained by modifying these unsaturated carboxylic acids and their derivatives, and their hydrogenated products. Specific examples of cyclic olefins include norbornene-based monomers. Examples of norbornene-based monomers include norbornene and its alkyl and/or alkylene substituents such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene , 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, etc., their halogen and other polar group substitutions; dicyclopenta Diene, 2,3-dihydrodicyclopentadiene, etc.; Dimethyl octahydronaphthalene, its alkyl and/or alkylene substituents, and polar group substituents such as halogens such as 6-methyl-1 ,4:5,8-Dimethylo-1,4,4a,5,6,7,8,8a-Octahydronaphthalene, 6-Ethyl-1,4:5,8-Dimetho-1, 4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylene-1,4:5,8-dimethylbridge-1,4,4a,5,6,7,8, 8a-octahydronaphthalene, 6-chloro-1,4:5,8-dimethylbridged-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4 :5,8-Dimethylbridge-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4:5,8-Dimethylbridge-1,4, 4a,5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4:5,8-dimethylbridge-1,4,4a,5,6,7,8,8a -Octahydronaphthalene, etc.; trimers to tetramers of cyclopentadiene such as 4,9:5,8-dimethyl bridge-3a,4,4a,5,8,8a,9,9a-octahydro- 1H-Benzindene, 4,11:5,10:6,9-trimethylbridge-3a,4,4a,5,5a,6,9,9a,10,10a,11,11a-dodecahydro-1H - cyclopentanthracene etc.

In the present invention, other ring-opening polymerizable cycloolefins may be used in combination within the range not impairing the object of the present invention. Specific examples of such cycloolefins include compounds having one reactive double bond, such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.

Regarding the above-mentioned cyclic olefin-based resin, the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) using a toluene solvent is preferably 25,000 to 200,000, more preferably 30,000 to 100,000, and most preferably 40,000 to 100,000. 80000. When the number average molecular weight is in the above range, excellent mechanical strength can be achieved, and solubility, moldability, and operability of casting can be improved.

When the above-mentioned cyclic olefin-based resin is obtained by hydrogenating a ring-opening polymer of a norbornene-based monomer, the hydrogenation rate is preferably 90% or more, more preferably 95% or more, most preferably 99% or more . When it is such a range, heat deterioration resistance, light deterioration resistance, etc. are excellent.

A commercially available film can also be used as the above-mentioned cyclic olefin-based resin film. As specific examples, the trade names "ZEONEX" and "ZEONOR" manufactured by Japan Zeon Corporation, the trade name "Arton" manufactured by JSR Corporation, the trade name "TOPAS" manufactured by TICONA, and the trade name manufactured by Mitsui Chemicals Co., Ltd. "APEL".

The first retardation layer 20 can be obtained, for example, by stretching a film made of the above-mentioned polycarbonate-based resin. As a method of forming a film from a cyclic olefin-based resin, any appropriate molding processing method can be adopted. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP (Fiber Reinforced Plastics; fiber reinforced plastics) molding, cast coating method (such as casting method), calendering method, hot pressing method, etc. Extrusion molding or cast coating is preferred. The reason for this is that the smoothness of the obtained thin film can be improved and good optical uniformity can be obtained. Molding conditions can be appropriately set according to the composition and type of resin to be used, desired properties of the retardation film, and the like. In addition, as mentioned above, since a large number of film products are commercially available in the cyclic olefin-based resin, this commercially available film can be directly subjected to stretching treatment.

The thickness of the resin film (unstretched film) can be set to any appropriate value according to the desired thickness of the first retardation film, desired optical characteristics, stretching conditions described later, and the like. Preferably, it is 50 μm to 300 μm.

Any appropriate stretching method and stretching conditions (for example, stretching temperature, stretching ratio, stretching direction) can be used for the above-mentioned stretching. Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end shrinkage, and fixed-end shrinkage can be used alone, or simultaneously or sequentially. The stretching direction can also be performed in various directions or dimensions such as the longitudinal direction, the width direction, the thickness direction, and the oblique direction. The stretching temperature is preferably Tg-30°C to Tg+60°C relative to the glass transition temperature (Tg) of the resin film, more preferably Tg-10°C to Tg+50°C.

By appropriately selecting the above-mentioned stretching method and stretching conditions, a retardation film having the above-mentioned desired optical properties (eg, refractive index properties, in-plane retardation, and Nz coefficient) can be obtained.

In one embodiment, the retardation film can be produced by continuously stretching an elongated resin film obliquely in a direction at a predetermined angle with respect to the longitudinal direction. By adopting oblique stretching, a long stretched film having an orientation angle (the slow axis in the direction of the angle) of a predetermined angle with respect to the longitudinal direction of the film can be obtained, for example, a roll can be realized when laminating with a polarizer For rollers, the manufacturing steps can be simplified. In addition, the angle may be an angle formed by the absorption axis of the polarizer in the optical laminate and the slow axis of the first retardation layer. As mentioned above, the angle is preferably 10° to 20°, more preferably 13° to 17°, and still more preferably about 15°.

As a stretching machine used for diagonal stretching, for example, a tenter type stretching machine that can add a feed force, a stretching force, or a pulling force at a laterally and/or longitudinally different speed can be used. The tenter-type stretching machine includes a transverse uniaxial stretching machine, a simultaneous biaxial stretching machine, and the like, and any appropriate stretching machine can be used as long as the elongated resin film can be continuously stretched obliquely.

By appropriately controlling the left and right speeds of the above-mentioned stretching machine, the first retardation layer (substantially a long retardation film) having the above-mentioned desired in-plane retardation and a slow axis in the above-mentioned desired direction can be obtained. ).

The stretching temperature of the above-mentioned film may vary depending on the desired in-plane retardation value and thickness of the first retardation layer, the type of resin used, the thickness of the film used, the stretching ratio, and the like. Specifically, the stretching temperature is preferably Tg-30°C to Tg+30°C, more preferably Tg-15°C to Tg+15°C, most preferably Tg-10°C to Tg+10°C. By stretching at such a temperature, a first retardation layer having appropriate characteristics can be obtained in the present invention. In addition, Tg is the glass transition temperature of the constituent material of a thin film.

C-3. First retardation layer composed of alignment solidified layer of liquid crystal compound

The first retardation layer 20 may also be an alignment solidified layer of a liquid crystal compound. By using a liquid crystal compound, the difference between nx and ny of the obtained retardation layer can be significantly increased compared with non-liquid crystal materials, and thus the thickness of the first retardation layer for obtaining a desired in-plane retardation can be significantly reduced . As a result, further thinning of the optical laminated body can be achieved. When the first retardation layer 20 is composed of an alignment-cured layer of a liquid crystal compound, its thickness is preferably 1 μm to 7 μm, more preferably 1.5 μm to 2.5 μm. By using a liquid crystal compound, it is possible to realize an in-plane retardation equivalent to that of a resin film with a thickness considerably thinner than that of a resin film.

In the present specification, an "alignment-hardened layer" refers to a layer in which a liquid crystal compound is aligned in a predetermined direction within a layer and its orientation state is fixed. In addition, the "alignment hardened layer" is a concept including the alignment hardened layer obtained by hardening a liquid crystal monomer as follows. In this embodiment, typically, the rod-shaped liquid crystal compound is aligned (horizontally aligned) in a state of being aligned in the direction of the slow axis of the first retardation layer. As a liquid crystal compound, the liquid crystal compound (nematic liquid crystal) whose liquid crystal phase is a nematic phase is mentioned, for example. As such liquid crystal compounds, for example, liquid crystal polymers and liquid crystal monomers can be used. The expression mechanism of the liquid crystallinity of the liquid crystal compound may be lyotropic or thermotropic. The liquid crystal polymer and the liquid crystal monomer may be used alone or in combination.

In the case where 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 alignment state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (that is, curing) the liquid crystal monomer. After aligning the liquid crystal monomers, for example, in the case of polymerizing or crosslinking the liquid crystal monomers, the alignment state described above can be fixed thereby. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by crosslinking, and these are non-liquid crystalline. Therefore, the formed first retardation layer does not undergo, for example, a transition to a liquid crystal phase, a glass phase, or a crystalline phase due to a change in temperature, which is unique to a liquid crystal compound. As a result, the first retardation layer is extremely excellent in stability against temperature changes.

The temperature range in which a liquid crystal monomer exhibits liquid crystallinity varies depending on its type. Specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, most preferably 60°C to 90°C.

Any appropriate liquid crystal monomer can be used as the above-mentioned liquid crystal monomer. For example, polymerizable mesogen compounds described in JP 2002-533742 (WO00/37585), EP358208 (US5211877), EP66137 (US4388453), WO93/22397, EP0261712, DE19504224, DE4408171, and GB2280445 can be used. Specific examples of such polymerizable mesogenic compounds include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Sillicon-CC3767. As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable.

The alignment solidified layer of the liquid crystal compound can be formed by performing an alignment treatment on the surface of a predetermined substrate, coating the surface with a coating liquid containing a liquid crystal compound to align the liquid crystal compound in a direction corresponding to the alignment treatment, And make this orientation state fixed. By using such an alignment treatment, the liquid crystal compound can be aligned in a predetermined direction with respect to the longitudinal direction of the elongated substrate, and as a result, the slow axis can be expressed in the predetermined direction of the formed retardation layer. For example, a retardation layer having a slow axis in a direction of 15° with respect to the elongated direction can be formed on the elongated substrate. Even when such a retardation layer is desired to have a slow axis in the oblique direction, it can be laminated using roll-to-roll, so that the productivity of the optical layered body can be significantly improved. In one embodiment, the substrate is any suitable resin film, and the alignment cured layer formed on the substrate can be transferred to the surface of the polarizer 10 . In another embodiment, the substrate can be the second protective layer 13 . In this case, the transfer step can be omitted, and since the formation of the oriented solidified layer (first retardation layer) is continuously laminated by roll-to-roll, productivity is further improved.

As the above-mentioned orientation treatment, any appropriate orientation treatment can be adopted. Specifically, mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment are mentioned. Specific examples of mechanical orientation treatment include rubbing treatment and stretching treatment. Specific examples of physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of chemical alignment treatment include oblique vapor deposition and photo-alignment treatment. Any appropriate conditions can be adopted for the treatment conditions of various orientation treatments according to the purpose.

Alignment of the liquid crystal compound is carried out by treating the liquid crystal compound at a temperature at which a liquid crystal phase develops depending on the type of the liquid crystal compound. By performing such a temperature treatment, the liquid crystal compound takes a liquid crystal state, and the liquid crystal compound is aligned according to the direction of the alignment treatment on the surface of the substrate.

In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is a polymerizable monomer or a crosslinkable monomer, the alignment state is fixed by subjecting the liquid crystal compound aligned as described above to a polymerization treatment or a crosslinking treatment.

Specific examples of liquid crystal compounds and details of a method for forming an alignment hardened layer are described in JP-A-2006-163343. The contents of the publication are incorporated in this specification as a reference.

D. Second retardation layer

D-1. Characteristics of the second retardation layer

As described above, the second retardation layer 30 has a slow axis. The angle formed by the slow axis of the second retardation layer 30 and the absorption axis of the polarizer 11 is preferably 65° to 85°, more preferably 72° to 78°, and even more preferably about 75°. The angle formed by the slow axis of the second retardation layer 30 and the slow axis of the first retardation layer 20 is preferably 52°-68°, more preferably 57°-63°, even more preferably about 60°. When the angle between the slow axis of the second retardation layer 30 and the absorption axis of the polarizer 11 falls within this range, the in-plane retardation of the first retardation layer can be set within a predetermined range as described above. , arrange the slow axis of the first retardation layer at a predetermined angle with respect to the absorption axis of the polarizer, and set the in-plane retardation of the second retardation layer to a predetermined range as described below, thereby obtaining a very An optical laminate having excellent circularly polarized light properties (resulting in very excellent antireflection properties).

The second retardation layer preferably has a refractive index characteristic showing the relationship of nx>ny≧nz. The in-plane retardation Re(550) of the second retardation layer is 110 nm to 125 nm, preferably 115 nm to 120 nm.

The dimensional change rate of the second retardation layer is preferably 1% or less, more preferably 0.95% or less. The smaller the dimensional change rate of the second retardation layer, the better. The lower limit of the dimensional change rate of the second retardation layer is, for example, 0.01%. In the case where the dimensional change rate of the second phase difference layer is in such a range, it is possible to remarkably suppress the generation of cracks in the conductive layer under high temperature and high humidity.

Other characteristics of the second retardation layer are as described for the first retardation layer in the above item C-1.

D-2. Second retardation layer made of resin film

When the second retardation layer is made of a resin film, its thickness is preferably 40 μm or less, preferably 25 μm to 35 μm. When the thickness of the second retardation layer is within such a range, a desired in-plane retardation can be obtained. When the second retardation layer is made of a resin film, its material, properties, production method, etc. are the same as those described for the first retardation layer in the above item C-2.

D-3. The second retardation layer composed of an alignment solidified layer of a liquid crystal compound

Like the first retardation layer, the second retardation layer 30 may be an alignment-cured layer of a liquid crystal compound. When the second retardation layer 30 is composed of an alignment-cured layer of a liquid crystal compound, its thickness is preferably 0.5 μm to 2 μm, more preferably 1 μm to 1.5 μm. When the second retardation layer is composed of an alignment solidified layer of a liquid crystal compound, its material, characteristics, production method, etc. are the same as those described for the first retardation layer in the above item C-3.

D-4. Combination of the first retardation layer and the second retardation layer

The first retardation layer and the second retardation layer can be used in any appropriate combination. Specifically, it may be that the first retardation layer is composed of a resin film and the second retardation layer is composed of an alignment solidified layer of a liquid crystal compound; it may be that the first retardation layer is composed of an alignment solidified layer of a liquid crystal compound and the second retardation The layer is made of a resin film; both the first retardation layer and the second retardation layer can be made of a resin film; or both the first retardation layer and the second retardation layer can be made of an alignment solidified layer of a liquid crystal compound. Preferably: when the first phase difference layer is made of a resin film, the second phase difference layer is also made of a resin film; The poor layer is also composed of an alignment solidified layer of a liquid crystal compound. In addition, when both the first retardation layer and the second retardation layer are made of a resin film, the first retardation layer and the second retardation layer may be the same, or may have different detailed configurations. The same applies to the case where both the first retardation layer and the second retardation layer are composed of an alignment-cured layer of a liquid crystal compound.

E. Conductive layer

The conductive layer can be oxidized on any suitable substrate by any suitable film-forming method (such as vacuum evaporation method, sputtering method, CVD (Chemical Vapor Deposition; chemical vapor deposition) method, ion plating method, spray method, etc.) Formed into a film. After film formation, heat processing (for example, 100 degreeC - 200 degreeC) may be performed as needed. By performing heat treatment, the amorphous film can be crystallized. Examples of metal oxides include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Indium oxide can also be doped with divalent metal ions or tetravalent metal ions. It is preferably an indium-based composite oxide, more preferably an indium-tin composite oxide (ITO). Indium-based composite oxides are characterized by high transmittance (for example, 80% or more) in the visible light region (380 nm to 780 nm) and low surface resistance per unit area.

In the case where the conductive layer contains a metal oxide, the thickness of the conductive layer is preferably 50 nm or less, more preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

The surface resistance value of the conductive layer is preferably 300 Ω/sq or less, more preferably 150 Ω/sq or less, and still more preferably 100 Ω/sq or less.

The conductive layer can be patterned as needed. Through patterning, conductive parts and insulating parts can be formed. As the layout method, any appropriate method can be adopted. Specific examples of the patterning method include wet etching and screen printing.

F. Substrate

As the substrate, any appropriate resin film can be used. It is preferably a resin film having excellent transparency. Specific examples of constituent materials include cyclic olefin-based resins, polycarbonate-based resins, cellulose-based resins, polyester-based resins, and acrylic resins.

As described above, the base material has an in-plane phase difference and a slow axis whose direction has a deviation in the width direction. As described above, according to the present invention, even in the case where there is variation in the properties in the width direction due to such a base material, when the optical laminate is cut into a predetermined size and applied to an image display device, it can The variation in the display characteristics of each product is reduced.

The thickness of the substrate is preferably 10 μm to 200 μm, more preferably 20 μm to 60 μm.

A hard coat layer (not shown) may also be provided between the conductive layer 41 and the substrate 42 as needed. As the hard coat layer, a hard coat layer having any appropriate constitution can be used. The thickness of the hard coat layer is, for example, 0.5 μm to 2 μm. Fine particles for reducing Newton's rings may be added to the hard coat layer as long as the haze is within the allowable range. Furthermore, an anchor coating for improving the adhesion of the conductive layer and/or for adjusting A refractive index adjustment layer of reflectance. Any appropriate configuration can be adopted as the anchor coat layer and the refractive index adjustment layer. The anchor coat layer and the refractive index adjustment layer may be thin layers of several nanometers to tens of nanometers.

Another hard coat layer may also be provided on the side opposite to the conductive layer of the substrate 42 (the outermost side of the optical laminate) as needed. The hard coat layer typically includes a binder resin layer and spherical particles, and the spherical particles protrude from the binder resin layer to form protrusions. The details of such a hard-coat layer are described in Unexamined-Japanese-Patent No. 2013-145547, and the description content of this publication is taken in this specification as a reference.

G. Others

The optical laminated body of embodiment of this invention may further contain another phase difference layer. The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. of other retardation layers can be appropriately set according to the purpose.

Practically, an adhesive layer (not shown) for attaching to the display unit is provided on the surface of the substrate 42 . A release film is preferably bonded to the surface of the pressure-sensitive adhesive layer before the optical laminate is used.

H. Image display device

The elongated optical layered body described in the above items A to G can be cut to a predetermined size and applied to an image display device. Therefore, the present invention includes an image display device using such an optical laminate. Representative examples of image display devices include liquid crystal display devices and organic EL display devices. The image display device according to the embodiment of the present invention includes the optical layered body described in the above-mentioned A-terms to G-terms cut to a predetermined size on the visually recognizable side. The optical laminate is stacked so that the conductive layer is on the display cell (for example, liquid crystal cell, organic EL cell) side (so that the polarizer is on the visual recognition side). That is, the image display device according to the embodiment of the present invention may be a so-called built-in touch panel type input display device in which a touch sensor is incorporated between a display unit (for example, a liquid crystal unit, an organic EL unit) and a polarizing plate. In this case, the touch sensor can be disposed between the conductive layer (or the conductive layer with the substrate) and the display unit. As far as the structure of the touch sensor is concerned, a well-known structure in the industry can be used, so detailed description is omitted.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, the measurement method of each characteristic is as follows.

(1) Thickness

About the retardation layer (alignment hardened layer of a liquid crystal compound) formed by coating, it measured by the interference film thickness measurement method using MCPD2000 made from Otsuka Electronics. For other thin films, measurement was performed using a digital micrometer (KC-351C manufactured by Anritsu Corporation).

(2) Phase difference

The refractive indices nx, ny, and nz of the retardation layer and the substrate used in Examples and Comparative Examples were measured by an automatic birefringence measurement device (manufactured by Oji Scientific Instruments, Ltd., automatic birefringence meter KOBRA-WPR). The measurement wavelengths of the in-plane retardation Re are 450 nm and 550 nm, the measurement wavelength of the thickness direction retardation Rth is 550 nm, and the measurement temperature is 23°C.

(3) The phase difference value and the deviation of the slow axis direction

Five samples of 50 mm x 50 mm were cut out at equal intervals in the width direction of the film roll (polycycloolefin film roll of Reference Example 5) constituting the base material with a base conductive layer used in Examples and Comparative Examples. The in-plane retardation Re(550) and the slow axis were determined for the cut sample using an automatic birefringence measuring device (manufactured by Oji Scientific Instruments, Ltd., automatic birefringence meter KOBRA-WPR). The maximum value (%) of the deviation from the set phase difference is set as the deviation of the phase difference value, and the maximum value of the deviation from the set slow axis direction is set as the deviation in the slow axis direction.

(4) Display characteristics of image display device

The smartphone (Galaxy-S5) manufactured by Samsung Wireless was disassembled to take out the organic EL panel. Five samples of 50 mm×50 mm were cut out at equal intervals in the width direction of the 500 mm-width optical laminate rolls obtained in Examples and Comparative Examples. The cut out sample was bonded to an organic EL panel, and the reflection color was confirmed visually. The evaluation criteria are as follows.

Good: Shows a neutral reflection tint and no difference is seen for the five samples

Poor: Although it is a neutral reflection tone, a difference in color is confirmed for each sample

[Reference Example 1: Production of Polarizer]

A long roll of polyvinyl alcohol (PVA)-based resin film (manufactured by Kuraray, product name "PE3000") with a thickness of 30 μm is stretched in the longitudinal direction by a roll stretching machine so that it becomes 5.9 times the longitudinal direction. Swelling, dyeing, crosslinking, and washing treatments were performed simultaneously while uniaxially stretching, and finally drying treatment was performed, thereby producing a polarizer 1 with a thickness of 12 μm.

Specifically, in the swelling treatment, the film was stretched to 2.2 times while being treated with pure water at 20°C. Next, the dyeing treatment stretches to 1.4 while performing treatment in an aqueous solution at 30° C. with a weight ratio of iodine and potassium iodide of 1:7 after adjusting the iodine concentration so that the individual transmittance of the obtained polarizer is 45.0%. times. Furthermore, a two-stage cross-linking treatment was used for the cross-linking treatment, and the first-stage cross-linking treatment was stretched to 1.2 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 40°C. The boric acid content of the aqueous solution of the first-stage crosslinking treatment was set to 5.0% by weight, and the potassium iodide content was set to 3.0% by weight. The cross-linking treatment of the second stage stretches to 1.6 times while being treated in an aqueous solution in which boric acid and potassium iodide are dissolved at 65°C. The boric acid content of the aqueous solution of the second-stage crosslinking treatment was set to 4.3% by weight, and the potassium iodide content was set to 5.0% by weight. In addition, the cleaning treatment was performed with a potassium iodide aqueous solution at 20°C. The potassium iodide content of the aqueous solution for cleaning treatment was set to 2.6% by weight. Finally, drying treatment was performed at 70° C. for 5 minutes to obtain a strip-shaped polarizer 1 .

A TAC film manufactured by Konica Minolta Corporation (product name: KC2UA, thickness: 25 μm, corresponding to the second protective layer) and a hard film on one side of the TAC film were bonded through a polyvinyl alcohol-based adhesive. The HC-TAC film (thickness: 32 μm, corresponding to the first protective layer) of the hard coat (HC) layer formed by the coating process was respectively attached to both sides of the obtained elongated polarizer 1 by roll-to-roll, thereby A strip-shaped polarizing plate 1 having a configuration of first protective layer/polarizer 1/second protective layer was obtained.

[Reference Example 2: Fabrication of a Liquid Crystal Alignment and Solidification Layer Constituting the First Retardation Layer]

10 g of a polymerizable liquid crystal (manufactured by BASF Corporation: trade name "Paliocolor LC242", represented by the following formula) showing a nematic liquid crystal phase and a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF Corporation: trade name "Irgacure 907" ”) 3 g was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

The surface of a long polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed with a rubbing cloth to perform orientation treatment. As far as the conditions of orientation treatment are concerned, the number of rubbing times (the number of rubbing rollers) is 1, the radius r of the rubbing roller is 76.89mm, the rotational speed nr of the rubbing roller is 1500rpm, and the film conveying speed v is 83mm/sec. The amount M was performed under the five conditions (a) to (e) shown in Table 1.

Table 1

Friction strength RS(mm) Pressing amount M(mm) condition (a) 2618 0.3 condition (b) 3491 0.4 condition (c) 4363 0.5 condition (d) 1745 0.2 condition (e) 873 0.1

The direction of the orientation treatment was set to be a -75° direction when viewed from the visual confirmation side with respect to the direction of the absorption axis of the polarizer when it was bonded to a polarizing plate. The above-mentioned liquid crystal coating liquid was coated on the alignment-treated surface with a bar coater, and heated and dried at 90° C. for 2 minutes, thereby aligning the liquid crystal compound. The alignment state of the liquid crystal compound was very good under the conditions (a) to (c). The orientation of the liquid crystal compound was slightly disturbed under the conditions (d) and (e), but it was at a level that was practically not a problem. The thus-formed liquid crystal layer was irradiated with light of 1 mJ/cm ² using a metal halide lamp to cure the liquid crystal layer, thereby forming a retardation layer (liquid crystal alignment solidified layer) 1 on the elongated PET film. The thickness of the retardation layer 1 was 2 μm, and the in-plane retardation Re(550) was 236 nm. Furthermore, the retardation layer 1 has a refractive index distribution of nx>ny=nz.

[Reference Example 3: Fabrication of a Liquid Crystal Alignment and Solidification Layer Constituting the Second Retardation Layer]

The surface of a long polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed with a rubbing cloth to perform orientation treatment. The direction of the orientation treatment was set to be a -15° direction when viewed from the visual confirmation side with respect to the direction of the absorption axis of the polarizer when it was bonded to a polarizing plate. The same liquid crystal coating solution as in Reference Example 2 was applied to the orientation-treated surface, and the liquid crystal compound was aligned and cured in the same manner as in Reference Example 2, thereby forming a retardation layer 2 on the elongated PET film. The thickness of the retardation layer 2 was 1.2 μm, and the in-plane retardation Re(550) was 115 nm. Furthermore, the retardation layer 2 has a refractive index distribution of nx>ny=nz.

[Reference Example 4: Fabrication of Retardation Film Constituting Retardation Layer]

Polymerization was performed using a batch polymerization apparatus comprising two vertical reactors equipped with stirring blades and a reflux cooler controlled to 100°C. 9,9-[4-(2-hydroxyethoxy)phenyl]fluorene (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenyl carbonate (DPC) and magnesium acetate The tetrahydrate was added so that BHEPF/ISB/DEG/DPC/magnesium acetate=0.348/0.490/0.162/1.005/1.00×10 ⁻⁵ in molar ratio. After the inside of the reactor was sufficiently replaced with nitrogen (oxygen concentration: 0.0005 to 0.001% by volume), it was heated with a heat medium, and stirring was started when the internal temperature reached 100°C. 40 minutes after the start of the temperature rise, the internal temperature was controlled to be 220° C. to maintain the temperature, and at the same time, the pressure was reduced, and it was set to 13.3 kPa 90 minutes after reaching 220° C. Introduce the by-product phenol vapor together with the polymerization reaction to the reflux cooler at 100°C, return some monomer components contained in the phenol vapor to the reactor, and introduce the uncondensed phenol vapor into the condenser at 45°C and recycle.

Nitrogen gas was introduced into the first reactor to temporarily return the pressure to atmospheric pressure, and then the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, the internal temperature was set to 240° C. and the pressure to 0.2 kPa within 50 minutes by starting the temperature rise and pressure reduction in the second reactor. Thereafter, polymerization is performed until a prescribed stirring power is achieved. When the specified power is reached, nitrogen is introduced into the reactor to restore the pressure, the reaction solution is extracted in the form of strands, and pelletized by a rotary cutter to obtain BHEPF/ISB/DEG=34.8/49.0/16.2[mol %] of polycarbonate resin A composed of copolymerization. The polycarbonate resin had a reduced viscosity of 0.430 dL/g and a glass transition temperature of 128°C.

The obtained polycarbonate resin was vacuum-dried at 80° C. for 5 hours, and then used with a single-screw extruder (manufactured by Isuzu Chemical Machinery Co., Ltd., screw diameter: 25 mm, barrel set temperature: 220° C.), T-die (Width: 900mm, set temperature: 220°C), cooling roll (set temperature: 125°C), and film forming device of the coiler, thereby producing a polycarbonate resin film with a thickness of 130 μm.

(diagonal stretch)

The polycarbonate resin film obtained as described above was obliquely stretched according to the method of Example 1 of JP-A-2014-194483 to obtain a retardation film. That is, using the apparatus shown in FIGS. 2 to 5 , it was subjected to preheating treatment, oblique stretching, and MD shrinking treatment with the distribution of the clip pitch shown in FIG. 6 to obtain a retardation film. In addition, as for the detailed structure of an apparatus, the description content of Unexamined-Japanese-Patent No. 2014-194483 is incorporated in this specification as a reference. The specific manufacturing steps of the retardation film are as follows: preheat the polycarbonate resin film (130 μm in thickness and 765 mm in width) to 142° C. in the preheating zone of the stretching device. In the preheating area, the clamp distance between the left and right clamps is 125mm. Secondly, when the film enters the first oblique stretching zone C1, start to increase the clamp distance of the right clamp, so that it increases from 125mm to 177.5mm in the first oblique stretching zone C1. The rate of change in fixture spacing was 1.42. In the first oblique stretching zone C1, the clamp spacing for the left side clamps starts to decrease from 125mm to 90mm in the first oblique stretching zone C1. The rate of change in fixture spacing was 0.72. Furthermore, when the film enters the second oblique stretching zone C2, start to increase the clamp distance of the left clamp, so that it increases from 90mm to 177.5mm in the second oblique stretching zone C2. On the other hand, the distance between the clamps of the right clamp is still maintained at 177.5mm in the second oblique stretching area C2. In addition, simultaneously with the above-mentioned oblique stretching, 1.9-fold stretching was also performed in the width direction. In addition, the above-mentioned oblique stretching was performed at 135°C.

(MD shrink processing)

Next, MD shrinkage treatment is performed on the shrinkage area. Specifically, reducing the clamp spacing from 177.5mm to 165mm for both the left and right clamps. The shrinkage rate in the MD shrinkage treatment was 7.0%.

A retardation film (thickness: 50 μm) was obtained in the above-mentioned manner. The Re(550) of the obtained retardation film was 141 nm, and the birefringence Δn _xy was 0.00282. The obtained retardation film was used as the retardation layer 3 .

[Reference Example 5: Production of Conductive Film (Conductive Layer with Substrate)]

A long polycycloolefin film having a thickness of 50 μm (manufactured by ZEONOR, trade name “ZEONOR (registered trademark)”) was used as a substrate. One side of the substrate is coated with an ultraviolet curable resin composition (manufactured by DIC Corporation, trade name "UNIDIC (registered trademark) RS29-120"), dried at 80° C. for 1 minute, and then cured by ultraviolet light to form a film having a thickness of 1.0μm hard coat. Next, acrylic spherical particles (manufactured by Soken Chemical Co., Ltd., trade name "MX- 180TA") 0.002 parts by weight of curable resin composition added with spherical particles, followed by UV curing to form a hard coat layer with a thickness of 1.0 μm. The polycycloolefin film obtained above was put into a sputtering apparatus, and an amorphous layer of indium tin oxide having a thickness of 27 nm was formed on the surface of the particle-free hard coat layer. Next, the polycycloolefin film formed with the amorphous layer of indium tin oxide was heat-treated in a furnace at 130° C. for 90 minutes to produce a transparent conductive film having a surface resistance of 100 Ω/sq. The in-plane retardation Re(550) of the substrate was 4 nm, the retardation variation in the width direction was 20%, and the orientation angle (slow axis direction) variation in the width direction was 2°.

[Reference Example 6: Production of Conductive Film (Conductive Layer with Substrate)]

A transparent conductive film having a surface resistance of 100 Ω/sq was produced in the same manner as in Reference Example 5, except that a 50 μm-thick PET film (manufactured by Toray, trade name “Lumirror #50”) was used as the substrate.

[Reference Example 7: Production of Adhesive Layer]

In a reaction vessel equipped with a condenser tube, a nitrogen introduction tube, a thermometer and a stirring device, 99 parts of butyl acrylate, 1.0 part of 4-hydroxybutyl acrylate and 0.3 parts of 2,2'-azobisisobutyronitrile were added together with ethyl acetate. The mixture in the reaction container was reacted at 60° C. for 4 hours under nitrogen flow, and ethyl acetate was added to the reaction liquid to obtain a solution containing an acrylic polymer having a weight average molecular weight of 1.65 million (solid content concentration: 30% ). 0.15 parts of dibenzoyl peroxide (manufactured by NOF Corporation: NyperBO-Y), 0.1 parts of trimethylolpropane xylene diisocyanate ( Mitsui Takeda Chemical Co., Ltd.: Takenate D110N) and 0.2 parts of a silane coupling agent (manufactured by Soken Chemical Co., Ltd.: A-100, acetoacetyl group-containing silane coupling agent) to obtain a solution for forming an adhesive layer. The above solution for forming an adhesive layer was applied to a spacer formed of a polyester film surface-treated with a silicone-based release agent, and heat-treated at 155° C. for 3 minutes to obtain a 15-μm-thick spacer. Adhesive layer A.

[Reference Example 8: Production of Adhesive Layer]

In a reaction vessel equipped with a condenser, a nitrogen introduction pipe, a thermometer, and a stirring device, 94.9 parts of butyl acrylate, 5 parts of acrylic acid, and 0.1 part of 2-hydroxyethyl acrylate were added together with 100 parts of these monomers (solid content). 0.3 parts of benzoyl peroxide with ethyl acetate. The mixture in the reaction container was reacted at 60° C. for 7 hours under nitrogen flow, and then ethyl acetate was added to the reaction liquid to obtain a solution containing an acrylic polymer with a weight average molecular weight of 2.2 million (solid content concentration: 30 wt. %). 0.6 parts of trimethylolpropane toluene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd.: Coronate L) and 0.075 parts of γ-glycidoxypropyl Methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403) was used to obtain a solution for forming an adhesive layer. The above solution for forming an adhesive layer was applied to a spacer formed of a polyester film surface-treated with a silicone-based release agent, and heat-treated at 155° C. for 3 minutes to obtain a 15-μm-thick spacer. Adhesive layer B.

[Example 1]

The second protective layer of the polarizing plate 1 and the retardation layer 1 were bonded by roll-to-roll through an acrylic adhesive having a thickness of 5 μm. As a result, the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer 1 was 15°. Next, the PET film on which the retardation layer 1 was formed was peeled off, and the retardation layer 2 was bonded to the peeled surface by roll-to-roll via an acrylic adhesive having a thickness of 5 μm. As a result, the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer 2 was 75°. Furthermore, the PET film in which the retardation layer 2 was formed was peeled off, and the circular polarizing plate 1 which has the structure of a polarizing plate/1st retardation layer/2nd retardation layer was obtained. The second retardation layer of the circular polarizing plate 1 and the conductive layer with the conductive layer of the base material obtained in Reference Example 5 are laminated by roll-to-roll through the adhesive layer A to obtain a strip shape (a roll with a width of 500 mm) shape) optical laminated body 1. The obtained optical layered body 1 was subjected to the evaluation of (4) above. The results are shown in Table 2.

[Comparative example 1]

The second protective layer of the polarizer 1 and the retardation layer 3 were laminated by roll-to-roll via an acrylic adhesive with a thickness of 12 μm to obtain a circular polarizing plate 2 having a polarizer/retardation layer configuration. As a result, the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer 3 was 45°. This configuration is optically substantially equivalent to the configuration in which two retardation layers are combined in Example 1. The retardation layer of the circular polarizing plate 2 was bonded to the conductive layer with the base conductive layer obtained in Reference Example 5 through the adhesive layer A to obtain a long (500 mm wide) optical laminate. 2. The obtained optical layered body 2 was subjected to the evaluation of (4) above. The results are shown in Table 2.

Table 2

﹡PC is polycarbonate resin film

<Evaluation>

From the comparison of the examples and comparative examples in Table 2, it can be seen that although the retardation of the base material formed with the conductive layer and the deviation in the width direction of the slow axis direction are the same, and the compensation function of the retardation layer is optically equivalent, but By performing optical compensation by combining two specific retardation layers as a retardation layer, it is possible to reduce the difference in the display characteristics of each product when cutting a wide roll-shaped optical laminated body into a predetermined size and applying it to an image display device. deviation.

Industrial availability

The optical laminate of the present invention can be suitably used for image display devices such as liquid crystal display devices and organic EL display devices, and can be used particularly suitably as an antireflection film for organic EL display devices. Furthermore, the optical laminated body of this invention can be used suitably for a built-in touch panel type input display device.

Symbol Description

10 polarizers

11 Polarizers

12 First layer of protection

13 Second protective layer

20 The first retardation layer

30 Second retardation layer

41 conductive layer

42 Substrate

100 optical stacks

Claims (6)

1. a kind of strip optical laminate successively has the protection comprising polarizer and positioned at at least side of the polarizer Layer polarizing film, first phase difference layer, second phase difference layer, conductive layer and with substrate made of the closely sealed stacking of the conductive layer,

Wherein, phase difference Re (550) is 3nm~6nm, the deviation of the phase difference of the substrate in the direction of the width in the face of the substrate It is 10%~30%, the deviation of the slow-axis direction of the substrate in the direction of the width is 1 °~5 °,

In the face of the first phase difference layer phase difference Re (550) be 220nm~250nm, the slow axis of the first phase difference layer with should The absorption axiss angulation of polarizer is 10 °~20 °,

In the face of the second phase difference layer phase difference Re (550) be 110nm~125nm, the slow axis of the second phase difference layer with should The absorption axiss angulation of polarizer is 65 °~85 °.

2. strip optical laminate as described in claim 1, is web-like.

3. strip optical laminate as described in claim 1, width is 500mm or more.

4. strip optical laminate as described in claim 1, wherein the first phase difference layer and the second phase are poor Layer is made of annular ethylene series resin film.

5. strip optical laminate as described in claim 1, wherein the first phase difference layer and the second phase are poor Layer is the orientation cured layer of liquid-crystal compounds.

6. a kind of image display device has the optical laminate described in claim 1 by severing for predetermined size.