JP6432122B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device.

  Image display devices are widely used in mobile phones, tablet terminals, personal computers, televisions, PDAs, electronic dictionaries, car navigation systems, music players, digital cameras, digital video cameras, and the like. As image display devices become smaller and lighter, their use is no longer limited to offices and indoors, but is also being used outdoors and while moving by car or train.

  Under such circumstances, the opportunity to visually recognize the image display device through a polarizing filter such as sunglasses is increasing. On the other hand, it has been proposed to use an oriented film for an image display device due to various factors. However, when an alignment film is used in the image display device, distortion occurs in the polarization characteristics of the light emitted from the polarizing plate due to its sub-refractive properties, and as a result, when the image is viewed with a polarizing filter, the color tone such as rainbow spots There is a problem that visibility deteriorates due to disturbance (Patent Document 1). Also, many image display devices are provided with a cover glass (hereinafter also referred to as “surface cover glass”) on the surface on the viewing side, and when subjected to an impact, there is a risk of scattering if it breaks. There is a problem that there is.

WO2011 / 058774

  Then, this invention makes it one objective to improve the visibility at the time of visually recognizing the image display apparatus in which the oriented film was used through the polarizing filter. Another object is to effectively prevent the surface cover glass of the image display device from being scattered when it is broken.

  The inventors of the present invention have repeated research day and night to solve the above problem, and by using a laminated glass in which a glass plate is bonded to both sides of an orientation film whose retardation is controlled, as a surface cover glass of an image display device, It has been found that the above problems can be solved. The present inventors have made further studies and improvements based on such knowledge, and have completed the present invention.

The representative present invention is as follows.
Item 1
(1) Image display cell,
(2) A polarizer disposed on the viewer side from the image display cell, and (3) glass plates bonded to both sides of an alignment film having a retardation of 3000 nm to 150,000 nm disposed on the viewer side from the polarizer. Glass laminate,
An image display apparatus.
Item 2
Item 2. The image display device according to Item 1, wherein an angle formed by a polarization axis of the polarizer and an alignment main axis of the alignment film is approximately 45 degrees.
Item 3
Item 3. The image display device according to Item 1 or 2, wherein the image display cell is a liquid crystal cell or an organic EL cell.

  According to the present invention, the visibility of the image display device is improved. In particular, a reduction in image quality typified by rainbow spots that occur when viewed through a polarizing filter is reduced. In this document, “rainbow spot” is a concept including “color spot”, “color shift”, and “interference color”. Further, according to the present invention, it is possible to effectively prevent the surface cover glass from scattering.

A typical sectional view of a typical organic electroluminescence display is shown. A typical sectional view of a typical liquid crystal display device is shown.

  An image display device typically includes an image display cell and a polarizing plate. An organic EL cell or a liquid crystal cell is typically used as the image display cell. A typical schematic diagram of an image display device (organic EL display device) using an organic EL cell as an image display cell is shown in FIG. 1, and a representative image display device (liquid crystal display device) using a liquid crystal cell as the image display cell is shown. A schematic diagram is shown in FIG. Hereinafter, a typical structure of the image display device will be described with reference to FIG. 1 or 2, but the structure of the image display device is not limited to these, and various modifications can be made.

  In this document, the side on which the image of the image display device is displayed (the side on which the human views the image) is called the “viewing side”, and the side opposite to the viewing side (that is, the organic that also functions as the light source in the organic EL display device) The side where the EL cell is set and the side where the light source is arranged in the liquid crystal display device) is referred to as the “light source side”. 1 and 2, the right side is the viewing side, and the left side is the light source side.

  As shown in FIG. 1, the organic EL display device (E1) may include an organic EL cell (E4), a polarizing plate (E5), and a touch panel (E6). A quarter wavelength plate (E16) may be provided between the organic EL cell (E4) and the polarizing plate (E5). The polarizing plate (E5) is typically provided on the viewing side of the organic EL cell (E4), and has a structure in which polarizer protective films (E10a, E10b) are laminated on both sides of a film called a polarizer (E8). Have. The touch panel (E6) is typically provided closer to the viewing side than the viewing side polarizing plate (E5). The touch panel (E6) typically has a structure in which two transparent conductive films (E11, E12) are arranged via spacers (E13). The transparent conductive films (E11, E12) have a structure in which a base film (E11a, E12a) and a transparent conductive layer (E11b, E12b) are laminated. On the light source side of the touch panel (E6), an anti-scattering film (E14) that is a transparent substrate may be provided via an arbitrary adhesive layer. A surface cover glass (E15) is provided on the viewing side of the viewing side polarizer of the image display device.

  As shown in FIG. 2, the liquid crystal display device (L1) may include a light source (L2), a liquid crystal cell (L4), and a touch panel (L6). Typically, polarizing plates (a light source side polarizing plate (L3) and a viewing side polarizing plate (L5)) are respectively provided on both the light source side and the viewing side of the liquid crystal cell (L4). Each polarizing plate (L3, L5) typically has a structure in which polarizer protective films (L9a, L9b, L10a, L10b) are laminated on both sides of a film called a polarizer (L7, L8). In this document, the polarizing plate (L5) existing on the viewing side from the image display cell is also referred to as “viewing-side polarizing plate”, and the polarizer (L8) constituting the polarizing plate is also referred to as “viewing-side polarizing plate”. The touch panel (L6) is typically provided on the viewing side with respect to the viewing side polarizing plate (L5). The touch panel (L6) typically has a structure in which two transparent conductive films (L11, L12) are arranged via spacers (L13). The transparent conductive films (L11, L12) have a structure in which a base film (L11a, L12a) and a transparent conductive layer (L11b, L12b) are laminated. Moreover, the scattering prevention film (L14) which is a transparent base | substrate can be provided in the light source side of a touchscreen (L6) through arbitrary adhesive layers. A surface cover glass (L15) is provided on the viewing side of the viewing side polarizer of the image display device.

  In the image display device shown in FIGS. 1 and 2, any member on the viewing side from the viewing side polarizer (E8, L8) is not essential. Therefore, for example, the anti-scattering films (E14, L14) are not essential and may be present as necessary.

  In the image display device, an alignment film can be used for the image display device for various purposes. In this document, the oriented film means a polymer film having birefringence. From the viewpoint of improving visibility, the image display device preferably includes a glass laminate in which glass plates are bonded to both surfaces of an alignment film having a retardation of 3000 μm or more and 150,000 nm or less on the viewing side from the viewing side polarizer. In this document, an oriented film having a retardation of 3000 μm or more and 150,000 nm or less is referred to as a “high retardation oriented film”.

  1 and 2, the touch panel (E6, L6) is shown on the viewing side of the viewing side polarizing plate (E5, L5), but the presence of the touch panel is not essential. When the image display device includes a touch panel, the touch panel is not limited to the above-described resistive film type touch panel, and other types of touch panels such as a projected capacitive type can be used. For example, the number of transparent conductive films may be one. The touch panel may be a built-in touch panel in which a touch panel function is incorporated in the image display cell. As the built-in touch panel, an in-cell touch panel in which touch sensing electrodes are arranged inside the two substrates of the image display cell, and an on-cell touch panel in which touch sensing electrodes are arranged outside the substrate on the viewing side of the display cell Etc.

  The touch panel may be a surface cover glass provided with a touch panel function. Examples of the touch panel provided with the touch panel function on the surface cover glass include the following (A) to (F), but are not limited thereto. (A) A touch sensor in which a transparent conductive layer, an insulating layer, and a transparent conductive layer are laminated in this order on the glass plate surface, and another glass plate not provided with the transparent conductive layer on both sides of the high retardation oriented film. A touch panel that is attached one by one. Here, the glass plate on which the transparent conductive layer is laminated is preferably laminated with the high retardation alignment film so that the transparent conductive layer does not contact the high retardation alignment film, but the transparent conductive layer is a high retardation alignment film. It may be pasted so that it touches. (B) A transparent conductive layer is provided on both surfaces of the glass plate, and a touch sensor using the glass plate as an insulating layer and another glass plate not provided with the transparent conductive layer are provided on both sides of the high retardation oriented film. A touch panel that has been bonded together. (C) a touch sensor using two glass laminates each provided with a single transparent conductive layer on one side of a glass plate, bonded to both sides of the high retardation alignment film, and using the high retardation alignment film as an insulating layer; Touch panel. Here, two glass laminated bodies are arrange | positioned so that the surface in which each transparent conductive layer was provided may contact the surface of a high retardation orientation film. (D) A touch panel in which a transparent conductive layer, an insulating layer, and a transparent conductive layer are provided in this order on one side of a high retardation oriented film to form a touch sensor, and glass plates are bonded to both sides thereof. (E) The touch panel which provided the transparent conductive layer on both surfaces of the high retardation orientation film as a touch sensor, and bonded the glass plate on both sides. (F) A touch panel in which transparent electrodes are provided on both sides of a laminated glass to form a touch sensor and further laminated with an arbitrary film or sheet.

  In the above, a typical example of a touch panel in which a touch panel function is provided on a surface cover glass has been described. However, a touch sensor is used between a transparent electrode provided on one side of a glass plate and a transparent electrode provided on one side of a high retardation alignment film. A function may be provided, and in the above (A) and (D), a single layer of the transparent electrode can be used as a touch sensor.

<Surface cover glass>
The surface cover glass is a laminated glass in which glass plates are bonded to both sides of the high retardation oriented film. As a glass plate constituting the surface cover glass, silica glass (SiO ₂ ), soda lime silica glass (Na ₂ O—CaO—SiO ₂ ), lead glass (K ₂ O—PbO—SiO ₂ ), borosilicate glass (Na ₂ O—B ₂ O ₃ —SiO ₂ ), alkali-free glass (XO—Al ₂ O ₃ —SiO ₂ X is a divalent element), or the like made of any material is used. A preferred glass plate is a soda-lime glass and / or aluminosilicate glass chemically strengthened.

  Moreover, you may use an organic inorganic composite sheet (for example, Sylplus) as a substitute of a glass plate. It is also preferable that the organic / inorganic composite sheet is bonded to both sides of the high retardation oriented film and that the organic / inorganic composite before curing is applied to both sides of the high retardation oriented film and then cured. What was shape | molded on such a film corresponds also to laminated glass. Application of the organic-inorganic composite onto the high retardation oriented film is preferable because it can be laminated without an adhesive. It is preferable to provide an easy adhesion layer on the surface of the high retardation oriented film.

  The thickness of the glass plate is arbitrary and can be appropriately set according to the size of the image display device, but is preferably 50 μm or more, more preferably 70 μm or more, still more preferably 100 μm or more from the viewpoint of maintaining the strength as the surface cover. It is. From the viewpoint of weight reduction, the upper limit of the thickness of the glass plate is preferably 2000 μm or less, more preferably 1500 μm or less, and still more preferably 1000 μm or less. In the case of a surface cover glass used for a small portable terminal, the glass plate constituting it is preferably 700 μm or less, more preferably 500 μm or less. When a plurality of glass plates are used in combination, their thicknesses may be the same or different.

  The thickness of the surface cover glass, which is a laminated glass, is also arbitrary and can be set as appropriate depending on the size of the image display device, but is preferably 100 μm or more, more preferably 150 μm or more from the viewpoint of strength. The upper limit of the thickness of the surface cover glass is preferably 4000 μm or less, more preferably 3000 μm or less, and still more preferably 2000 μm or less from the viewpoint of weight reduction. In the case of a cover glass used for a small portable terminal, the thickness is preferably 1500 μm or less, more preferably 1000 μm or less.

  The viewing side of the surface cover glass is also preferably subjected to a surface treatment such as an antireflection layer (low reflection layer), an antiglare layer, an antireflection (low reflection) antiglare layer, an antistatic layer, or an antifouling layer. It is also preferable to provide an antireflection layer (low reflection layer) on the light source side of the surface cover glass.

<High retardation oriented film>
The lower limit of the retardation of the high retardation oriented film is 3000 nm or more. Furthermore, from the viewpoint of effectively reducing rainbow spots, the thickness is preferably 4500 nm or more, preferably 6000 nm or more, preferably 8000 nm or more, preferably 10,000 nm or more. On the other hand, the upper limit of the retardation of the high retardation oriented film is that even if a polyester film having a higher retardation is used, the effect of further improving the visibility is not substantially obtained, and the orientation depends on the height of the retardation. Since the thickness of the film also tends to increase, it is set to 150,000 nm from the viewpoint that it may be against the demand for thinning, but it is theoretically possible to make it higher. When the image display device has two or more high retardation alignment films, the retardations may be the same or different.

  The thickness of the high retardation oriented film is preferably 5 μm or more, more preferably 10 μm or more, and particularly preferably 15 μm or more from the viewpoint of securing a high retardation and ensuring a scattering prevention function as a laminated glass. The upper limit of the thickness is preferably 250 μm or less, more preferably 200 μm or less, and particularly preferably 170 μm or less in terms of thinness and weight reduction.

  From the standpoint of more effectively suppressing rainbow spots, the high retardation oriented film has a ratio (Re / Rth) of the retardation (Re) and thickness direction retardation (Rth) of preferably 0.2 or more, Preferably it is 0.5 or more, preferably 0.6 or more. The thickness direction retardation means an average value of retardation obtained by multiplying two birefringences ΔNxz and ΔNyz by the film thickness d when viewed from the cross section in the thickness direction of the film. As Re / Rth is larger, the birefringence action is more isotropic, and the generation of rainbow spots on the screen can be more effectively suppressed. In this document, when simply described as “retardation”, it means in-plane retardation.

  The maximum value of Re / Rth is 2.0 (that is, a perfect uniaxial symmetry film), but the mechanical strength in the direction perpendicular to the orientation direction tends to decrease as the perfect uniaxial symmetry film is approached. is there. Therefore, the upper limit of Re / Rth of the polyester film is preferably 1.2 or less, and preferably 1.0 or less. Even if the ratio is 1.0 or less, it is possible to satisfy the viewing angle characteristics (180 degrees left and right, 120 degrees up and down) required for the image display device.

  The retardation of the oriented film can be measured according to a known method. Specifically, it can be determined by measuring the refractive index and thickness in the biaxial direction. Moreover, it can also obtain | require using the commercially available automatic birefringence measuring apparatus (For example, KOBRA-21ADH: Oji Scientific Instruments Co., Ltd. make).

  The high retardation alignment film can be produced by appropriately selecting a known method. For example, high retardation alignment films include polyester resins, polycarbonate resins, polystyrene resins, syndiotactic polystyrene resins, polyether ether ketone resins, polyphenylene sulfide resins, cycloolefin resins, liquid crystalline polymer resins, and cellulosic resins. It can be produced using one or more selected from the group consisting of added resins. Therefore, high retardation alignment film is a polyester film, polycarbonate film, polystyrene film, syndiotactic polystyrene film, polyetheretherketone film, polyphenylene sulfide film, cycloolefin film, liquid crystalline film, and liquid crystal compound added to cellulose resin. Film.

  A preferred raw material resin for the high retardation oriented film is polycarbonate and / or polyester and syndiotactic polystyrene. These resins are excellent in transparency and excellent in thermal and mechanical properties, and the retardation can be easily controlled by stretching. Polyesters typified by polyethylene terephthalate and polyethylene naphthalate are preferable because they have a large intrinsic birefringence, and relatively large retardation can be obtained even when the film thickness is thin. In particular, polyethylene naphthalate has a large intrinsic birefringence among polyesters, and therefore is suitable for a case where it is desired to make the retardation particularly high or a case where it is desired to reduce the film thickness while keeping the retardation high. A more specific method for producing a high retardation oriented film will be described later using a polyester resin as a representative example.

<Method for producing high retardation oriented film>
Below, the manufacturing method of a highly retardation orientation film is demonstrated to a polyester film as an example. The polyester film can be obtained by condensing an arbitrary dicarboxylic acid and a diol. Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and diphenylcarboxylic acid. Acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalate Acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, azelaic acid, Dimer , It may be mentioned sebacic acid, suberic acid, dodecamethylene dicarboxylic acid.

  Examples of the diol include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, 1,4 -Butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone and the like can be mentioned.

  Each of the dicarboxylic acid component and the diol component constituting the polyester film may be used alone or in combination of two or more. Specific polyester resins constituting the polyester film include, for example, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc., preferably polyethylene terephthalate and polyethylene naphthalate, more preferably polyethylene terephthalate. is there. The polyester resin may contain other copolymer components, and from the viewpoint of mechanical strength, the proportion of the copolymer components is preferably 3 mol% or less, more preferably 2 mol% or less, still more preferably 1.5 mol% or less. is there. These resins are excellent in transparency and excellent in thermal and mechanical properties. Moreover, retardation of these resins can be easily controlled by stretching.

  The polyester film can be obtained according to a general production method. Specifically, the polyester resin is melted and the non-oriented polyester extruded and formed into a sheet shape is stretched in the longitudinal direction by utilizing the speed difference of the roll at a temperature equal to or higher than the glass transition temperature, and then in the transverse direction by a tenter. An oriented polyester film is mentioned by extending | stretching and heat-processing. The polyester film may be a uniaxially stretched film or a biaxially stretched film. The high retardation oriented film may be stretched at an angle of 45 degrees.

  Manufacturing conditions for obtaining a polyester film can be appropriately set according to a known method. For example, the longitudinal stretching temperature and the transverse stretching temperature are usually 80 to 130 ° C, preferably 90 to 120 ° C. The longitudinal draw ratio is usually 1.0 to 3.5 times, preferably 1.0 to 3.0 times. The transverse draw ratio is usually 2.5 to 6.0 times, preferably 3.0 to 5.5 times.

  Controlling the retardation within a specific range can be performed by appropriately setting the stretching ratio, stretching temperature, and film thickness. For example, it becomes easier to obtain a higher retardation as the stretching ratio between the longitudinal stretching and the lateral stretching is higher, the stretching temperature is lower, and the film is thicker. On the contrary, it becomes easier to obtain a lower retardation as the stretching ratio between the longitudinal stretching and the lateral stretching is lower, the stretching temperature is higher, and the film thickness is thinner. Moreover, the higher the stretching temperature and the lower the total stretching ratio, the easier it is to obtain a film having a lower ratio of retardation to thickness direction (Re / Rth). Conversely, a film having a higher ratio of retardation to thickness direction retardation (Re / Rth) can be obtained as the stretching temperature is lower and the total stretching ratio is higher. Furthermore, the heat treatment temperature is usually preferably 140 to 240 ° C, and preferably 180 to 240 ° C.

  In order to suppress the fluctuation of the retardation in the polyester film, it is preferable that the thickness unevenness of the film is small. If the longitudinal stretching ratio is lowered to make a retardation difference, the value of the longitudinal thickness unevenness may be increased. Since there is a region where the value of the vertical thickness unevenness becomes very high in a specific range of the draw ratio, it is desirable to set the film forming conditions so as to exclude such a range.

The thickness unevenness of the oriented polyester film is preferably 5.0% or less, more preferably 4.5% or less, still more preferably 4.0% or less, and 3.0% or less. It is particularly preferred. The thickness unevenness of the film can be measured by any means. For example, a tape-like sample (length: 3 m) continuous in the film flow direction is collected and 100 cm at a 1 cm pitch using a commercially available measuring instrument (for example, an electronic micrometer, Millitron 1240 manufactured by Seiko EM Co., Ltd.). The thickness of the point is measured, the maximum value (dmax), the minimum value (dmin), and the average value (d) of the thickness are obtained, and the thickness unevenness (%) can be calculated by the following formula.
Thickness unevenness (%) = ((dmax−dmin) / d) × 100

<Adhesive>
An adhesive is preferably used for bonding the high retardation alignment film and the glass plate. Examples of the adhesive include polyvinyl butyral, ethylene-vinyl acetate copolymer, silicone resin, epoxy resin, polyurethane resin, polyester resin, acrylic resin, and modified products thereof. Among these, polyvinyl butyral and ethylene-vinyl acetate copolymer are preferable.

  The method of using the adhesive is not particularly limited. For example, a method using an adhesive molded into a sheet, a method using a glass coating, a method using a high retardation oriented film, a coating on a release film. Examples thereof include a method of transferring the prepared pressure-sensitive adhesive to glass or a high retardation oriented film.

  The thickness of the adhesive layer is arbitrary and can be set as appropriate. For example, in the case of a coated adhesive, the lower limit is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, and the upper limit is preferably 100 μm or less, more preferably 50 μm or less, 30 μm or less is preferable. In the case of the adhesive formed on the sheet, the lower limit of the thickness of the adhesive layer is preferably 2 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and the upper limit is preferably 100 μm or less. It is preferably 50 μm or less, particularly preferably 30 μm or less.

<Lamination method>
A method for producing a laminated glass by laminating a glass plate and a high retardation oriented film is arbitrary and not particularly limited. For example, a laminated glass by laminating a glass plate, an adhesive, a high retardation oriented film, an adhesive, and a glass plate in this order, bringing the layers into close contact with each other while removing bubbles by applying pressure with a roller, etc. Can be obtained. In addition, it is preferable not only to pressurize but also to remove bubbles sandwiched by pressure reduction during lamination to bonding treatment.

  The adhesion treatment can be performed by performing various treatments suitable for the adhesive. For example, if it is a thermoadhesive adhesive, it can be carried out by thermocompression bonding above the softening temperature. A reaction-curing adhesive in which a curing agent such as isocyanate and / or epoxy is added to the adhesive can be carried out by thermocompression bonding at room temperature or higher so that curing proceeds. If it is an ultraviolet curable adhesive, it can be implemented by irradiating with ultraviolet rays.

  Lamination of a glass plate and a high retardation alignment film is not only a glass plate, a high retardation alignment film, and a glass plate, but also a high retardation alignment film, a retardation film of 3000 nm or less, and a glass plate, either alone or in combination. It can also be laminated.

  The high retardation oriented film may be used not only as a single substance, but also in a plurality of layers, or may be used as a film obtained by laminating a high retardation oriented film and a retardation film of 3000 nm or less.

<Easy adhesion treatment of high retardation oriented film>
The high retardation oriented film is preferably subjected to an easy adhesion treatment in order to ensure adhesiveness with an adhesive when bonded to a glass plate. The easy adhesion treatment can be appropriately selected depending on the material of the high retardation alignment film and the adhesive. For example, physical treatment such as corona treatment and plasma treatment, and an easy adhesion coat can be mentioned, but an easy adhesion coat is preferred.

  As the resin used for the easy-adhesive coating agent, for example, when the high retardation oriented film is a polyester, a copolymer polyester, a polyester polyurethane, a polycarbonate polyurethane, an acrylic resin, or the like is preferably used. These resins are preferably used in combination of two different resins, for example, acrylic resin and polyester resin, acrylic resin and urethane resin, or polyester resin and urethane resin. This is because the properties of the two types of resins are maintained and the adhesion is further improved.

  Preferred acrylic resins include copolymers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, glycidyl methacrylate, and acrylic acid. The glass transition temperature of the acrylic resin is preferably 0 to 90 ° C, more preferably 10 to 80 ° C. The number average molecular weight of the acrylic resin is preferably 100,000 or more, and more preferably 300,000 or more from the viewpoint of adhesiveness.

  Preferable polyester resins include copolymers selected from terephthalic acid, isophthalic acid, ethylene glycol, neopentyl glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol. The glass transition temperature of the polyester resin is preferably 10 to 90 ° C, more preferably 20 to 80 ° C. The number average molecular weight of the polyester resin is preferably 15000 or more, and 17000 or more is particularly desirable in terms of adhesiveness.

  A preferred polyester polyurethane is one obtained by reacting the above polyester resin or an oligomer thereof with a diisocyanate compound. Preferred polycarbonate polyurethane resins include those obtained by reacting an aliphatic polycarbonate diol with a diisocyanate compound. As the diisocyanate compound, tolylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate and the like can be used. In obtaining a polyurethane resin, a low molecular weight chain extender may be used. The glass transition temperature of the polyurethane resin is preferably 0 to 60 ° C, more preferably 10 to 50 ° C. The number average molecular weight of the polyurethane resin is preferably 15000 or more, and 17000 or more is particularly desirable in terms of adhesiveness.

  It is also preferable to add a polyvinyl alcohol-based resin to the easy-adhesion coating agent in order to ensure adhesion. The polyvinyl alcohol-based resin is not particularly limited. For example, polyvinyl alcohol obtained by saponifying polyvinyl acetate; a derivative thereof; and a saponified product of a copolymer of vinyl acetate and a monomer having copolymerizability; And modified polyvinyl alcohol obtained by converting polyvinyl alcohol into acetalized, urethanized, etherified, grafted, phosphoric acid ester or the like. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene, (meth) Examples include allyl sulfonic acid (soda), sulfonic acid soda (monoalkyl malate), disulfonic acid soda alkyl maleate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, N-vinyl pyrrolidone, N-vinyl pyrrolidone derivatives, and the like. . These polyvinyl alcohol resins may be used alone or in combination of two or more.

  Examples of the polyvinyl alcohol resin include vinyl alcohol-vinyl acetate copolymer, vinyl alcohol-vinyl butyral copolymer, and ethylene-vinyl alcohol copolymer. Among these, vinyl alcohol-vinyl acetate copolymer, ethylene- A vinyl alcohol copolymer is preferred. The degree of polymerization of the polyvinyl alcohol-based resin is not particularly limited, but the degree of polymerization is preferably 3000 or less from the viewpoint of the viscosity of the coating solution.

  The saponification degree of the polyvinyl alcohol-based resin is preferably 60 mol% or more and 85 mol% or less, and more preferably 65 mol% or more and 83 mol% or less.

  As content of a polyvinyl alcohol-type resin, 10 mass% or more and 60 mass% or less are preferable in an easily bonding coat layer, and 15 mass% or more and 55% mass% or less are more preferable.

  It is preferable that a crosslinking agent is added to the easy adhesion coating agent. Examples of the crosslinking agent include isocyanate compounds, amino resins such as melamine, oxazoline compounds, epoxy compounds, and carbodiimide compounds.

  In addition, a leveling agent, an antifoaming agent, an antistatic agent, and the like can be added to the easy adhesion coating agent.

  It is also preferable to add a lubricant such as silica to the easy-adhesion coat without adding a particle lubricant to the high retardation oriented film in order to ensure high transparency and handleability of the film. The particles preferably have an average particle diameter (number-based average particle diameter by SEM; the same applies hereinafter), 0.04 to 2.0 μm, and more preferably 0.1 to 1.0 μm.

  The easy adhesion coating agent may be an organic solvent type or an aqueous type, but an aqueous type is preferable in terms of handling. The resin is preferably dissolved or dispersed in an aqueous system, and a resin into which a carboxylate group or a sulfonate group is introduced is preferable. The easy-adhesive coating agent may be an in-line coat that is coated at the time of manufacturing the easy-adhesive coat film or an off-line coat that is coated after the film is manufactured.

<Installation of surface cover film>
The angle at which the surface cover glass is arranged in the image display device is arbitrary, but the angle formed by the alignment principal axis of the high retardation alignment film constituting the surface cover glass and the polarization axis of the viewing side polarizer (high retardation alignment film and (It is assumed that the polarizer is on the same plane), but is not particularly limited, but is preferably close to 45 degrees (approximately 45 degrees) from the viewpoint of reducing rainbow spots and reducing luminance. For example, the angle is 45 ° ± 30 ° or less, preferably 45 ° ± 20 ° or less, preferably 45 ° ± 15 °, preferably 45 ° ± 10, preferably 45 ° ± 5 °, preferably 45 ° ±. They are 3 degrees, 45 degrees ± 2 degrees, 45 degrees ± 1 degree, and 45 degrees. In this document, the term “below” means that only the value following “±” is applied. Therefore, for example, the “45 degrees ± 20 degrees or less” means that the fluctuation in the range of 20 degrees above and below 45 degrees is allowed.

  As described above, the polarizer and the high retardation alignment film are arranged so that the polarization axis and the alignment main axis satisfy a certain angle. For example, the high retardation alignment film is cut and the alignment main axis is the polarization axis of the polarizer. And a method of disposing the film so as to have a specific angle, and a method of obliquely stretching a high retardation oriented film.

  From the viewpoint of obtaining better visibility by avoiding rainbow spots etc., when viewing an image display device using a polarizing filter, the polarization axis of the polarizing filter and the viewing side polarizer (and light source side polarizer) The angle formed by the polarization axis is preferably substantially parallel or substantially perpendicular. Here, “substantially parallel” is preferably 0 ° ± 10 ° or less, preferably 0 ° ± 5 ° or less, preferably 0 ° ± 4 ° or less, preferably 0 ° ± 3 °. Or less, preferably 0 ° ± 2 ° or less, and preferably 0 ° ± 1 ° or less. The term “substantially perpendicular” is preferably 90 ° ± 10 ° or less, preferably 90 ° ± 5 ° or less, preferably 90 ° ± 4 ° or less, and preferably 90 ° ± 3 ° or less. It is preferably 90 ° ± 2 ° or less, and preferably 90 ° ± 1 ° or less.

  Polarization filters such as polarized sunglasses are usually designed so that the polarization axis when attached is in a direction perpendicular to the horizontal. Therefore, from the viewpoint of obtaining better visibility when viewing the image display device through such a polarizing filter, in the image display device, the polarizer is a substantially rectangular display vertical axis or horizontal axis. It is preferable to arrange so as to be parallel to each other.

  The orientation main axis of the high retardation oriented film is preferably arranged in the image display device so as to be parallel to the vertical or horizontal axis of the rectangular display screen. When the orientation axis of the high retardation oriented film is approximately parallel to the vertical axis of the display, rainbow spots are suppressed and the visibility is excellent even when the screen is observed from an oblique direction (from the lateral direction) rather than from the front. is there. On the other hand, when the orientation main axis of the high retardation oriented film substantially coincides with the horizontal direction of the display screen, rainbow spots are suppressed and the visibility is excellent even when the screen is observed from an oblique direction (from the vertical direction) instead of from the front. Because.

  The surface cover glass may be overlapped with an internal member via a spacer, or may be bonded to the internal member with a baseless optical adhesive.

<Image display cell and light source>
In the image display device, it is preferable that the light emitted from the image display cell has a continuous and wide emission spectrum from the viewpoint of suppressing rainbow spots. Here, the “continuous and broad emission spectrum” means an emission spectrum in which there is no wavelength region where the light intensity becomes zero in the wavelength region of at least 450 to 650 nm, preferably in the visible light region. The visible light region is, for example, a wavelength region of 400 to 760 nm, and may be 360 to 760 nm, 400 to 830 nm, or 360 to 830 nm.

  When the image display device includes an organic EL cell as an image display cell, the organic EL cell itself has a function as a light source having a continuous and wide emission spectrum. On the other hand, when the image display device includes a liquid crystal cell as the image display cell, it is preferable to include a white light source having a continuous and broad emission spectrum.

  The method and structure of the white light source having a continuous and broad emission spectrum are not particularly limited, and may be, for example, an edge light method or a direct type. Examples of such a white light source include a white light emitting diode (white LED). White LEDs include phosphor-type LEDs (that is, elements that emit white light by combining phosphors and light emitting diodes that emit blue light and ultraviolet light using compound semiconductors) and organic light-emitting diodes (Organic light-emitting diodes). : OLED). A white light-emitting element that combines a blue light-emitting diode using a compound semiconductor with a yttrium, aluminum, and garnet-based yellow phosphor from the viewpoint of having a continuous and broad emission spectrum and excellent luminous efficiency. Light emitting diodes are preferred.

<Polarizing plate and polarizer protective film>
The polarizing plate has a structure in which both sides of a film-like polarizer are sandwiched between two protective films (sometimes referred to as “polarizer protective film”). As the polarizer, any polarizer (or polarizing film) used in the technical field can be appropriately selected and used. Representative polarizers include those obtained by dyeing a dichroic material such as iodine on a polyvinyl alcohol (PVA) film or the like, but are not limited to this, and are known and will be developed in the future. A polarizer to be obtained can be appropriately selected and used.

  Commercially available products can be used as the PVA film. For example, “Kuraray Vinylon (manufactured by Kuraray Co., Ltd.)”, “Toselo Vinylon (manufactured by Toh Cello Co., Ltd.)”, “Nichigo Vinylon (Nippon Synthetic Chemical Co., Ltd.) The dichroic material includes iodine, a diazo compound, a polymethine dye, and the like.

  The polarizer can be obtained by any method. For example, a PVA film dyed with a dichroic material is uniaxially stretched in an aqueous boric acid solution, and washed and dried while maintaining the stretched state. Can be obtained. The stretching ratio of uniaxial stretching is usually about 4 to 8 times, but is not particularly limited. Other manufacturing conditions and the like can be appropriately set according to known methods.

  The viewing side protective film (viewing side polarizer protective film) of the viewing side polarizer is conventionally used as a high retardation oriented film having a retardation value of 3000 nm or more, an oriented film having a retardation value of less than 3000 nm, or a polarizer protecting film. However, the film does not have any birefringence, but is not limited thereto. An oriented film having a retardation value of less than 3000 nm can be obtained by adjusting the film thickness and stretching conditions using the same material as that of the high retardation oriented film. Examples of the film having no birefringence include a triacetyl cellulose (TAC) film, an acrylic film, and a cyclic olefin-based film (for example, a norbornene-based film), a polypropylene film, and the like from the viewpoints of handleability and availability. Examples thereof include a polyolefin film (for example, TPX).

  The type of the protective film on the light source side of the viewing side polarizer and the protective film of the light source side polarizer is arbitrary, and a film conventionally used as a protective film can be appropriately selected and used. A film that does not have an is mentioned as a preferred example.

  In one embodiment, the light source side protective film of the viewer side polarizer and the viewer side protective film of the light source side polarizer are preferably optical compensation films having an optical compensation function. Such an optical compensation film can be appropriately selected according to each type of image display cell. For example, a liquid crystal compound (for example, a discotic liquid crystal compound and / or a birefringent compound) is dispersed in triacetyl cellulose. Resin, cyclic olefin resin (for example, norbornene resin), propionyl acetate resin, polycarbonate film resin, acrylic resin, styrene acrylonitrile copolymer resin, lactone ring-containing resin, imide group-containing polyolefin resin, and the like. The thing obtained from 1 or more types can be mentioned.

  Since the optical compensation film is commercially available, they can be appropriately selected and used. For example, “Wideview-EA” and “Wideview-T” (made by Fujifilm) for TN system, “Wideview-B” (made by Fujifilm) for VA system, VA-TAC (Konica Minolta, Inc.) ), “ZEONOR FILM” (manufactured by ZEON CORPORATION), “ARTON” (manufactured by JSR), “X-plate” (manufactured by Nitto Denko), and “Z-TAC” (manufactured by FUJIFILM Corporation) for the IPS system ), “CIG” (manufactured by Nitto Denko Corporation), “P-TAC” (manufactured by Okura Kogyo Co., Ltd.), and the like.

  The polarizer protective film can be laminated on the polarizer directly or via an adhesive layer. From the viewpoint of improving adhesiveness, it is preferable to laminate via an adhesive. The adhesive is not particularly limited and any adhesive can be used. From the viewpoint of thinning the adhesive layer, an aqueous one (that is, an adhesive component dissolved in water or dispersed in water) is preferable. For example, when using a polyester film as a polarizer protective film, a polyvinyl alcohol resin, a urethane resin, or the like is used as a main component, and an isocyanate compound, an epoxy compound, or the like is blended as necessary in order to improve adhesiveness. The composition can be used as an adhesive. The thickness of the adhesive layer is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less.

  When a TAC film is used as the polarizer protective film, it can be bonded using a polyvinyl alcohol-based adhesive. When using a film with low moisture permeability such as an acrylic film, a cyclic olefin film, a polypropylene film, or TPX as the polarizer protective film, it is preferable to use a photocurable adhesive as the adhesive. Examples of the photocurable resin include a mixture of a photocurable epoxy resin and a photocationic polymerization initiator.

  The thickness of the polarizer protective film is arbitrary, and can be appropriately set, for example, in the range of 15 to 300 μm, preferably in the range of 30 to 200 μm.

<Touch panel, transparent conductive film, base film, anti-scattering film>
The image display device may include a touch panel. The type and method of the touch panel are not particularly limited, and examples include a resistive touch panel and a capacitive touch panel. The touch panel usually has one or more transparent conductive films regardless of the method. The transparent conductive film has a structure in which a transparent conductive layer is laminated on a base film. As the substrate film, a highly retardation oriented film having a retardation value of 3000 nm or more, an oriented film having a retardation value of less than 3000 nm, a film having no birefringence, or a rigid plate such as a glass plate can be used. Among these, a polyester resin, a polycarbonate resin, and a polyolefin resin are preferable, and a polyester resin is more preferable.

  Although the thickness of a base film is arbitrary, the range of 15-500 micrometers is preferable.

  The base film may be subjected to etching treatment or undercoating treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, etc. on the surface in advance. Thereby, adhesiveness with the transparent conductive layer etc. which are provided on a base film can be improved. Moreover, before providing a transparent conductive layer etc., you may remove and clean the surface of a base film by solvent washing | cleaning, ultrasonic washing | cleaning, etc. as needed.

The transparent conductive layer may be directly laminated on the base film, but can be laminated via an easy adhesion layer and / or various other layers. Examples of the other layer include a hard coat layer, an index matching (IM) layer, and a low refractive index layer. As a typical laminated structure of the transparent conductive film, the following 6 patterns can be exemplified, but the invention is not limited thereto.
(1) Base film / easy adhesion layer / transparent conductive layer (2) Base film / easy adhesion layer / hard coat layer / transparent conductive layer (3) Base film / easy adhesion layer / IM (index matching) layer / Transparent conductive layer (4) Base film / Easily adhesive layer / Hard coat layer / IM (Index matching) layer / Transparent conductive layer (5) Base film / Easily adhesive layer / Hard coat layer (High refractive index doubles as IM ) / Transparent conductive layer (6) Polyester film / Easily adhesive layer / Hard coat layer (high refractive index) / Low refractive index layer / Transparent conductive thin film

  Since the IM layer itself has a laminated structure of a high refractive index layer / low refractive index layer (the transparent conductive thin film side is a low refractive index layer), the ITO layer is used when the liquid crystal display screen is viewed. Can be difficult to see. As described in (6) above, the high refractive index layer of the IM layer and the hard coat layer can be integrated, which is preferable from the viewpoint of thickness reduction.

  The configurations (3) to (6) are particularly suitable for use in a capacitive touch panel. Moreover, the structure of said (2)-(6) is preferable from a viewpoint that an oligomer can prevent depositing on the surface of a base film, and providing a hard-coat layer also on the other one side of a base film. preferable.

  The transparent conductive layer on the base film is formed of a conductive metal oxide. The conductive metal oxide constituting the transparent conductive layer is not particularly limited, and is selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten. A conductive metal oxide of at least one selected metal is used. The metal oxide may further contain a metal atom shown in the above group, if necessary. Preferred transparent conductive layers are, for example, a tin-doped indium oxide (ITO) layer and an antimony-doped tin oxide (ATO) layer, and more preferably an ITO layer. Alternatively, Ag nanowires, Ag inks, Ag ink self-assembled conductive films, mesh electrodes, CNT inks, and conductive polymers may be used.

The thickness of the transparent conductive layer is not particularly limited, but is preferably 10 nm or more, more preferably 15 to 40 nm, and even more preferably 20 to 30 nm. When the thickness of the transparent conductive layer is 15 nm or more, a good continuous film having a surface resistance of 1 × 10 ³ Ω / □ or less is easily obtained. Moreover, it can be set as a layer with higher transparency as the thickness of a transparent conductive layer is 40 nm or less.

  The transparent conductive layer can be formed according to a known procedure. For example, a vacuum deposition method, a sputtering method, and an ion plating method can be exemplified. The transparent conductive layer may be amorphous or crystalline. As a method for forming a crystalline transparent conductive layer, it is preferable to form an amorphous film once on a substrate and then heat and crystallize the amorphous film together with a flexible transparent substrate.

  The transparent conductive film may be patterned by removing a part of the surface of the transparent conductive layer. The transparent conductive film in which the transparent conductive layer is patterned has a pattern forming part in which the transparent conductive layer is formed on the base film and a pattern opening having no transparent conductive layer on the base film. Have. Examples of the shape of the pattern forming portion include a stripe shape, a square shape, and the like.

  The image display device may further be provided with a scattering prevention film. As the scattering prevention film, a highly retardation oriented film having a retardation value of 3000 nm or more, an oriented film having a retardation value of less than 3000 nm, a film having no birefringence, or a rigid plate such as a glass plate can be used. Among these, a polyester resin, a polycarbonate resin, and a polyolefin resin are preferable, and a polyester resin is more preferable.

  Although the thickness of a scattering prevention film is arbitrary, the range of 15-500 micrometers is preferable.

<Angle of viewing side polarizer protective film, electrode base film, or scattering prevention film of viewing side polarizer>
When the viewing side polarizer protective film, the base film or the scattering prevention film of the viewing side polarizer is an oriented film having a retardation of 150 nm or more or a highly retardation oriented film, the orientation main axis of the film and the polarization of the viewing side polarizer The angle formed by the axis (assuming that the film and the polarizer are on the same plane) is not particularly limited, but is 0 ° ± 30 ° or less, preferably 0, from the viewpoint of reducing rainbow spots. The degree is ± 25 degrees or less, preferably 0 degrees ± 20 degrees or less, preferably 0 degrees ± 10 degrees or less, and preferably 0 degrees ± 5 degrees or less. Further, it is preferably 90 ° ± 30 ° or less, preferably 90 ° ± 25 ° or less, preferably 90 ° ± 20 ° or less, preferably 90 ° ± 10 ° or less, preferably 90 ° ± 5 degrees or less.

  Further, when the viewing side polarizer protective film, the base film or the scattering prevention film of the viewing side polarizer is a high retardation oriented film having a retardation of 3000 nm or more, the orientation main axis of the high retardation oriented film and the viewing side polarizer It is also preferable that the angle formed by the polarization axis is close to 45 degrees (approximately 45 degrees). For example, the angle is 45 ° ± 30 ° or less, preferably 45 ° ± 20 ° or less, preferably 45 ° ± 15 °, preferably 45 ° ± 10, preferably 45 ° ± 5 °, preferably 45 ° ±. They are 3 degrees, 45 degrees ± 2 degrees, 45 degrees ± 1 degree, and 45 degrees. In this document, the term “below” means that only the value following “±” is applied.

  The polarizer protective film, the base film, and the high retardation oriented film can contain various additives as long as the effects of the present invention are not hindered. For example, ultraviolet absorbers, inorganic particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, light proofing agents, flame retardants, thermal stabilizers, antioxidants, anti-gelling agents And surfactants. Moreover, in order to show high transparency, it is also preferable that a polyester film does not contain a particle | grain substantially. “Substantially free of particles” means, for example, in the case of inorganic particles, when the inorganic element is quantified by fluorescent X-ray analysis, the content is 50 ppm or less, preferably 10 ppm or less, particularly preferably the detection limit or less. Means quantity.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and is implemented with appropriate modifications within a range that can be adapted to the gist of the present invention. These are all included in the technical scope of the present invention.

<Configuration of image display device>
(1) Backlight light source: White LED
(2) Polarizing plate on light source side and viewing side: TAC film (manufactured by Fuji Film Co., Ltd., thickness 80 μm) is used as a protective film on both sides of a polarizer made of PVA and iodine.
(3) Image display cell: Liquid crystal cell (4) Surface cover glass: Prepared by the procedure described later.

(Synthesis of resin for film)
Production Example-PET (A)
When the temperature of the esterification reactor was raised to 200 ° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were charged and 0.017 parts by mass of antimony trioxide as a catalyst while stirring. 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine were charged. Subsequently, the pressure was raised and the esterification reaction was performed under the conditions of a gauge pressure of 0.34 MPa and 240 ° C., and then the esterification reaction vessel was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Furthermore, it heated up to 260 degreeC over 15 minutes, and 0.012 mass part of trimethyl phosphate was added. Then, after 15 minutes, dispersion treatment was performed with a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can and subjected to polycondensation reaction at 280 ° C. under reduced pressure.

  After the completion of the polycondensation reaction, filtration is performed with a filter made of NASRON (registered trademark) with a 95% cut diameter of 5 μm, extruded into a strand form from a nozzle, and using cooling water that has been previously filtered (pore diameter: 1 μm or less). It was cooled and solidified and cut into pellets. The obtained polyethylene terephthalate resin (A) had an intrinsic viscosity of 0.62 dl / g and contained substantially no inert particles and internally precipitated particles. (Hereafter, abbreviated as PET (A).)

(Polymerization of polyester resin for easy adhesion coating)
In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 194.2 parts by weight of dimethyl terephthalate, 184.5 parts by weight of dimethyl isophthalate, 14.8 parts by weight of dimethyl-5-sodium sulfoisophthalate, The mixture was charged with 233.5 parts by mass of diethylene glycol, 136.6 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate, and subjected to a transesterification reaction at a temperature of 160 to 220 ° C. over 4 hours. Next, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and the mixture was reacted for 1 hour 30 minutes under a reduced pressure of 30 Pa to obtain a copolyester resin. The obtained copolyester resin was light yellow and transparent. The reduced viscosity of the copolyester resin was measured and found to be 0.70 dl / g. The glass transition temperature by DSC was 40 ° C.

(Preparation of polyester aqueous dispersion for easy adhesion coating)
In a reactor equipped with a stirrer, a thermometer and a reflux device, 30 parts by mass of a copolyester resin and 15 parts by mass of ethylene glycol n-butyl ether were added and heated and stirred at 110 ° C. to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution while stirring. After the addition, the solution was cooled to room temperature while stirring to prepare a milky white copolymerized polyester aqueous dispersion having a solid content of 30% by mass.

(Preparation of aqueous polyvinyl alcohol solution for easy adhesion coating)
In a container equipped with a stirrer and a thermometer, 90 parts by mass of water was added, and 10 parts by mass of polyvinyl alcohol resin (manufactured by Kuraray) having a polymerization degree of 500 and a saponification degree of 74 mol% was gradually added while stirring. After the addition, the solution was heated to 95 ° C. while stirring to dissolve the resin. After dissolution, the mixture was cooled to room temperature while stirring to prepare an aqueous polyvinyl alcohol solution having a solid content of 10% by mass.

(Polymerization of block polyisocyanate crosslinking agent)
In a flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of a polyisocyanate compound having an isocyanurate structure using hexamethylene diisocyanate as a raw material (manufactured by Asahi Kasei Chemicals, Duranate TPA), 55 parts by mass of propylene glycol monomethyl ether acetate, polyethylene 30 parts by mass of glycol monomethyl ether (average molecular weight 750) was charged, and kept at 70 ° C. for 4 hours under a nitrogen atmosphere. Thereafter, the reaction solution temperature was lowered to 50 ° C., and 47 parts by mass of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction solution was measured to confirm that the absorption of the isocyanate group had disappeared, and a block polyisocyanate aqueous dispersion having a solid content of 75% by mass was obtained.

(1) Preparation of coating solution The following coating agent was mixed to prepare a coating solution having a mass ratio of copolymerized polyester resin / polyvinyl alcohol resin of 70/30.
Water 40.61 mass%
Isopropanol 30.00% by mass
Polyester water dispersion 11.67% by mass
Polyvinyl alcohol aqueous solution 15.00% by mass
Block isocyanate-based crosslinking agent 0.67% by mass
1.25% by mass of particles
(Silica sol with an average particle size of 100 nm, solid content concentration of 40% by mass)
Catalyst (Organic tin compound, solid content concentration 14% by mass) 0.3% by mass
Surfactant 0.5% by mass
(Silicone, solid content concentration 10% by mass)

Oriented film 1
After drying under reduced pressure (1 Torr) at 135 ° C. for 6 hours with PET (A) resin pellets containing no particles as a base film raw material, it was supplied to an extruder and dissolved at 285 ° C. This polymer is filtered with a filter material of stainless sintered body (nominal filtration accuracy 10 μm particles 95% cut), extruded into a sheet form from the die, and then applied to a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method. It was wound and solidified by cooling to make an unstretched film.

Next, the above coating solution was applied to both sides of the unstretched PET film by a reverse roll method so that the coating amount after drying was 0.08 g / m ^2, and then dried at 80 ° C. for 20 seconds.

  The unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction. Next, while maintaining the width stretched in the width direction, the film is treated at a temperature of 225 ° C. for 30 seconds, and further subjected to a relaxation treatment of 3% in the width direction to obtain a uniaxially oriented film 1 having a film thickness of about 50 μm. It was.

Oriented film 2
A uniaxially oriented oriented film 2 was obtained in the same manner as the oriented film 1 except that the thickness of the unstretched film was changed to about 100 μm.

Oriented film 3
A biaxially oriented film 3 having a film thickness of about 75 μm was obtained in the same manner as the oriented film 3 except that the film was stretched 3.3 times in the running direction and 4.0 times in the width direction.

Oriented film 4
A uniaxially oriented film 4 having a film thickness of about 100 μm was obtained in the same manner as the oriented film 3 except that the film was stretched 4.0 times in the running direction and 1.0 times in the width direction.

Oriented film 5
A biaxially oriented oriented film 5 having a film thickness of about 38 μm was obtained in the same manner as the oriented film 3 except that the film was stretched 3.6 times in the running direction and 4.0 times in the width direction.

Oriented film 6
Polycarbonate (manufactured by Aldrich) was dissolved in methylene chloride 4 times by weight to prepare a polymer solution. The polymer solution was developed into a smooth glass plate with a knife coater and allowed to stand at room temperature to dry the solvent. Thereafter, the polycarbonate sheet was peeled off from the glass plate and dried in a vacuum dryer at 90 ° C. for 24 hours. A sample was cut out in a dumbbell shape from the obtained polycarbonate sheet. The cut sheet sample was heated to about 160 ° C. using Tensilon (manufactured by Orientec) and stretched in the uniaxial direction. By adjusting the draw ratio and the draw speed at that time, the uniaxially oriented oriented film 6 having a retardation of 9087 nm was obtained.

  Table 1 shows the physical properties of the obtained film.

  In addition, retardation (Re) and thickness direction retardation (Rth) were measured as follows. That is, using two polarizing plates, the orientation principal axis direction of the film was obtained, and a 4 cm × 2 cm rectangle was cut out so that the orientation principal axis directions were orthogonal to each other, and used as a measurement sample. For this sample, the biaxial refractive index (Nx, Ny) perpendicular to each other and the refractive index (Nz) in the thickness direction were determined by an Abbe refractometer (NAR-4T, manufactured by Atago Co., Ltd.). The absolute value of the difference (| Nx−Ny |) was determined as the anisotropy (ΔNxy) of the refractive index. The thickness d (nm) of the film was measured using an electric micrometer (manufactured by Fine Reef, Millitron 1245D), and the unit was converted to nm. Retardation (Re) was determined from the product (ΔNxy × d) of refractive index anisotropy (ΔNxy) and film thickness d (nm). Further, Nx, Ny, Nz and film thickness d (nm) are obtained by the same method as the measurement of retardation, and the average value of (ΔNxz × d) and (ΔNyz × d) is calculated to obtain a thickness direction retardation ( Rth) was determined.

(Creation of front cover glass)
Lamination was carried out in the order of glass plate / adhesive layer / high retardation oriented film / adhesive layer / glass plate, and thermocompression bonded under reduced pressure at 100 ° C. to obtain a laminated glass. The materials used are as follows.
Glass: Chemically reinforced aluminosilicate glass (100 mm x 70 mm, thickness 300 μm) with antireflection layer on the surface
Adhesive layer: ethylene vinyl acetate copolymer (S-LEC (TM) manufactured by Sekisui Chemical Co., Ltd.) with a thickness of 0.38 μm is heated and spread with a Teflon (TM) roll to a thickness of 0.2 μm. Used for transfer.
High retardation oriented film: The above oriented films 1 to 6 were used. For reference, a laminated glass was prepared without using a high retardation oriented film.

Test Example 1: Erythema evaluation (effect of retardation)
In the image display device having the above configuration, the polarizing axis of the viewing side polarizer and the orientation main axis of the high retardation orientation film of the surface cover glass are installed at an angle of 45 degrees, and the viewing side surface is parallel to the viewing side surface. In addition, the polarizing film was arranged so that the angle formed by the polarizing axis of the polarizing film and the polarizing axis of the viewing side polarizer of the image display device was 90 degrees to display a white image. A white image was viewed through a polarizing film to confirm the presence or absence and the extent of iridescence, and evaluated according to the following criteria.

<Evaluation criteria>
A: When observed from the front, no rainbow spots are observed.
○: When observed from the front, a weak rainbow was observed.
X: When observing from the front, rainbow spots were clearly observed or the brightness decreased.

  The results are shown in Table 2. From Table 2, it was found that rainbow spots were effectively reduced when the retardation of the film used for the surface cover glass was 3000 nm or more.

Test Example 2: Evaluation of luminance (influence of angle of high retardation oriented film)
In the image display device having the above-described configuration, a surface cover glass using the alignment film 2 is installed, and the viewing side surface is parallel to the viewing side surface and the polarization axis of the polarizing film and the viewing side polarizer of the image display device The polarizing film was arranged so that the angle formed by the polarization axis was 90 degrees, and a white image was displayed. The angle between the orientation main axis of the high retardation orientation film used for the surface cover glass and the polarization axis of the viewing side polarizer was rotated every 5 degrees from 0 to 90 degrees, and the white image was viewed through the polarizing film for evaluation. However, it became like Table 3.

Test Example 3: Visibility when an alignment film is provided between the polarizer and the surface cover glass In the image display device having the above-described configuration, the polarization axis of the viewing side polarizer using the surface cover glass using the alignment film 2 In addition, the orientation axis of the high retardation oriented film of the surface cover glass is set at an angle of 45 degrees, and the viewing side surface is parallel to the viewing side surface and the polarizing axis of the polarizing film and the viewing side polarizer of the image display device A polarizing film was arranged so that the angle formed by the polarization axis of the film was 90 degrees, and a white image was displayed. Further, assuming that an alignment film was used for the polarizer complementary film, the electrode substrate film, etc. of the new side polarizing plate, a polyester film (A4300, manufactured by Toyobo Co., Ltd.) having a retardation of 1537 nm and a thickness of 50 μm was applied to the viewing side polarizing plate and the surface. The angle was changed between the cover glasses, and the white image was viewed through the polarizing film to confirm the presence and extent of rainbow spots. No rainbow spots were observed from the front even if the polyester film had any angle of polarization axis of the viewing side polarizer.

Test Example 4: Visibility when a high retardation alignment film is provided between the polarizer and the surface cover glass In Test Example 3, the high retardation alignment film used for the surface cover glass is the alignment film 1 or 4, and instead of the polyester film. Oriented films 1 to 4 and 6 were inserted. In addition, the orientation film instead of the polyester film was inserted so that the orientation main axis | shaft of the orientation film used for the surface cover glass and the orientation film inserted might be 30 degree | times.

  When the oriented film used for the front cover glass and the inserted oriented film are the same, an iris is observed when the oriented film 1 is used for the surface cover glass and the oriented film 3 is inserted. Was not recognized.

E1 Organic EL display device E4 Organic EL cell E5 Viewing side polarizing plate E6 Touch panel E7 Light source side polarizer E8 Viewing side polarizer E9a Polarizer protection film E9b Polarizer protection film E10a Polarizer protection film E10b Viewing side polarizer protection film E11 Light source Side transparent conductive film E11a Light source side base film E11b Transparent conductive layer E12 Viewing side transparent conductive film E12a Viewing side base film E12b Transparent conductive layer E13 Spacer E14 Light source side scattering prevention film E15 Surface cover glass E16 1/4 wavelength plate L1 Liquid crystal display device L2 Light source L3 Light source side polarizing plate L4 Liquid crystal cell L5 Viewing side polarizing plate L6 Touch panel L7 Light source side polarizer L8 Viewing side polarizer L9a Polarizer protection film L9b Polarizer protection film L10a Polarizer protection film L10b Viewing side polarization Child Protection Film L11 light source side transparent conductive film L11a source side substrate film L11b transparent conductive layer L12 viewing side transparent conductive film L12a viewing side substrate film L12b transparent conductive layer L13 spacer L14 light source side shatterproof film L15 front cover glass

Claims (5)

(1) Image display cell,
(2) A polarizer disposed on the viewer side from the image display cell, and (3) A glass plate on both sides of an alignment film having a retardation of 3000 nm to 150,000 nm disposed on the viewer side from the polarizer. A glass laminate directly bonded via
Have
The thickness of the glass plate is 100 μm or more,
The orientation film has a thickness of 100 μm or less,
The alignment film is a polyester film,
Image display device. The image display device according to claim 1, wherein the oriented film is an oriented film in which at least one film surface is subjected to easy adhesion treatment. The image display device according to claim 1, wherein an angle formed by a polarization axis of the polarizer and an alignment main axis of the alignment film is approximately 45 degrees. The image display device according to claim 1, wherein the image display cell is a liquid crystal cell or an organic EL cell. (1) Organic EL cell,
(2) A polarizer disposed on the viewing side from the organic EL cell ,
(3) a touch panel disposed closer to the viewer than the polarizer , and
(4) A glass laminate in which glass plates are bonded to both surfaces of an alignment film having a retardation of 3000 nm or more and 150,000 nm or less , which is disposed on the viewer side from the touch panel ,
An image display apparatus.

Images