JP2014157286A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device with improved visibility.SOLUTION: An image display device includes: (1) image display cell; (2) a polarizer placed closer to the viewing side than the image display cell; and (3) an oriented film which is placed closer to the viewing side than the polarizer and which has thickness of 200 to 500 μm, and 3000 to 150000 nm retardation.

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. Further, as a relatively new image display device, a flexible display that is flexible and can be arranged on a curved surface is expected to be put to practical use.

  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 alignment films for various purposes in image display devices including flexible displays. 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).

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.

  The inventors of the present invention have conducted research day and night to solve the above problems, and have found that the above problems can be solved by controlling the retardation of the oriented film. 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.
(1) Image display cell,
(2) A polarizer disposed on the viewer side from the image display cell, and (3) a retardation having a thickness of 200 μm or more and 500 μm or less and 3000 nm or more and 150,000 nm or less disposed on the viewer side of the polarizer. An image display device having an alignment film.
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 device is a flexible image display device.

  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”.

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. A schematic cross-sectional view of a typical organic EL cell 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. For example, a suitable specific example of the image display device is a flexible display that can be bent and can be bent, and various modifications (for example, replacement of a glass substrate with a plastic substrate) can be made. Is possible. The basic structures of the organic EL display device and the liquid crystal display device shown in FIGS. 1 and 2 are the same in the case of the flexible organic EL image display device and the flexible liquid crystal display device, respectively.

  In this document, the side of the image display device on which the image is displayed (the side on which a human views the image) is called the “viewing side”, and the side opposite to the viewing side (that is, 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 and the viewing side of the touch panel (E6), an anti-scattering film (E14, E15) that is a transparent substrate may be provided via an arbitrary adhesive layer.

  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, L15) which is a transparent base | substrate can be provided in the light source side and visual recognition side of a touchscreen (L6) through arbitrary adhesive layers.

  In FIGS. 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 and may have any film. For example, one scattering prevention film may be provided on the viewing side of the viewing side polarizing plate. The touch panel is not limited to the resistive film type touch panel described above, 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 scattering prevention film does not necessarily have to be disposed on both sides of the touch panel, and may be configured to be disposed on either side or may not be disposed on both sides.

<Position of oriented film>
In the image display device, an oriented film can be used for various purposes. In this document, the oriented film means a polymer film having birefringence. The image display device preferably has an alignment film having a retardation of 3000 nm or more and 150,000 nm or less on the viewing side from the viewing side polarizer from the viewpoint of improving visibility. In this document, an oriented film having a retardation of 3000 nm to 150,000 nm is also referred to as “high retardation oriented film”. Therefore, in the image display device shown in FIGS. 1 and 2, the alignment film is typically a polarizer protective film (E10b, L10b) (hereinafter referred to as “viewing side”) on the viewing side from the viewing side polarizer (E8, L8). The substrate film (E11a, L11a) of the transparent conductive film (E11, L11) located on the light source side from the spacer (E13, L13) (hereinafter referred to as “light source side substrate film”). ), Base film (E12a, L12a) of transparent conductive film (E12, L12) on the viewer side from spacer (E13, L13) (hereinafter referred to as “viewer side substrate film”), viewer side polarizer protection Anti-scattering film (E14, L14) between the film (E10b, L10b) and the light source side base film (E11a, L11a) (hereinafter, “light source” And / or a scattering prevention film (E15, L15) (hereinafter referred to as “viewing side scattering prevention film”) on the viewing side from the viewing side base film (E12a, L12a). .

  In a preferred embodiment, the image display device includes a high retardation alignment film as a viewing-side scattering prevention film. In this case, the thickness of the high retardation oriented film is not particularly limited, but is preferably 200 μm or more and 500 μm or less, more preferably 300 μm or more and 450 μm or less. By providing a high retardation oriented film having a thickness of 200 μm or more and 500 μm or less as an anti-scattering film, the generation of rainbow spots is suppressed, the strength is such that it can be replaced with tempered glass, and the flexibility required for flexible displays It can be set as the scattering prevention film which has the property. Therefore, in the image display device having such a configuration, the image display device can be used as a flexible display by using a plastic substrate having flexibility instead of using a rigid substrate such as a glass substrate having low flexibility. Is possible.

  The lower limit value of the retardation of the high retardation oriented film is preferably 4500 nm or more, preferably 6000 nm or more, preferably 8000 nm or more, preferably 10000 nm or more from the viewpoint of reducing rainbow spots. 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.

  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 angle formed by the alignment axis of the high retardation alignment film and the polarization axis of the viewing side polarizer (assuming that the high retardation alignment film and the polarizer are on the same plane) is not particularly limited, but reduces rainbow spots. From the viewpoint of achieving this, it is preferably close to 45 degrees (approximately 45 degrees). For example, the angle is 45 ° ± 20 ° or less, preferably 45 ° ± 15 °, preferably 45 ° ± 10, preferably 45 ° ± 5 °, preferably 45 ° ± 3 °, 45 ° ± 2 °, 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.

  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 image display device may have a retardation alignment film of less than 3000 nm at any position as long as at least one high retardation alignment film is provided on the viewing side of the viewing side polarizer. Such oriented films are known and can be obtained commercially.

  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, polyetheretherketone 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 oriented film>
Below, the manufacturing method of the oriented film containing a highly retardation oriented 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

<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.

  As the organic EL cell, an organic EL cell known in the technical field can be appropriately selected and used. Use of the organic EL cell is preferable in terms of wide viewing angle, high contrast, and high-speed response. A schematic cross-sectional view of a typical organic EL cell is shown in FIG. The organic EL cell (E4) typically has an anode (E18) that is a transparent electrode, an organic light emitting layer (E19), and a cathode (E20) that is a metal electrode on a transparent substrate (E17) in this order from the viewing side. It is the light-emitting body (organic electroluminescent light-emitting body) which has the structure laminated | stacked by. The organic EL cell emits light by recombination of holes injected from the anode and electrons injected from the cathode in the organic light emitting layer when a voltage is applied between the anode and the cathode. To do.

  Any transparent substrate can be adopted as the transparent substrate. For example, it can be selected from the group consisting of a glass substrate, a ceramic substrate, a semiconductor substrate, a metal substrate, and a plastic substrate. When the image display device is a flexible organic EL display device, the transparent substrate is preferably a transparent substrate having flexibility, for example, a transparent plastic substrate. The transparent substrate may be provided with a surface treatment layer as required. Examples of the surface treatment layer include a moisture permeation prevention layer, a gas barrier layer, a hard coat layer, an undercoat layer, and the like.

  Examples of the material constituting the anode and the cathode include metals, metal oxides, alloys, electrically conductive compounds, and mixtures thereof. More specific materials constituting the anode include metals such as gold, silver, chromium, and nickel; conductive transparent materials such as copper iodide, indium tin oxide (ITO), tin oxide, and zinc oxide. More specific materials constituting the cathode include magnesium, aluminum, indium, lithium, sodium, cesium, silver, magnesium-silver alloy, magnesium-indium alloy, and lithium-aluminum alloy.

  The thickness of the anode can be arbitrarily set according to the material constituting the anode, and can be appropriately set, for example, in the range of 10 nm to 200 nm, preferably 10 nm to 100 nm. The thickness of the cathode can be arbitrarily set according to the material constituting the anode, for example, 10 nm to 1000 nm, preferably 10 nm to 200 nm.

  The organic light emitting layer is a layer having a function of emitting light by providing a recombination field of holes and electrons when a voltage is applied. The organic light emitting layer contains an organic light emitting material and may have a single layer structure or a laminated structure of two or more layers. In the case of a laminated structure, each layer may emit light with different emission colors. The thickness of the organic light emitting layer is arbitrary, and can be appropriately set within a range of 3 nm to 3 μm, for example.

  The organic light emitting material used for the organic light emitting layer can be appropriately selected from arbitrary light emitting materials. Specifically, olefin-based light emitting materials such as 4,4 ′-(2,2-diphenylvinyl) biphenyl; 9,10-di (2-naphthyl) anthracene, 9,10-bis (3,5-diphenylphenyl) ) Anthracene, 9,10-bis (9,9-dimethylfluorenyl) anthracene, 9,10- (4- (2,2-diphenylvinyl) phenyl) anthracene, 9,10′-bis (2-biphenylyl) Anthracene-based luminescent materials such as -9,9'-bisanthracene, 9,10,9 ', 10'-tetraphenyl-2,2'-bianthryl, 1,4-bis (9-phenyl-10-anthracene) benzene Spiro-based luminescent materials such as 2,7,2 ′, 7′-tetrakis (2,2-diphenylvinyl) spirobifluorene; 4,4′-dicarbazolbiphenyl, 1,3 Can be appropriately selected from the group consisting of pyrene based light emitting material such as 1,3,5-tri pin renin benzene; carbazole luminescent material such as di-carbazolyl benzene.

  The organic EL cell includes a sealing member formed so as to cover the organic EL element in order to block the organic EL element including the anode, the organic light emitting layer, and the cathode on the base material from the outside air. Also good. By providing the sealing member, it is possible to prevent deterioration of the light emitting characteristics of the organic light emitting layer due to moisture and oxygen in the outside air.

  The organic EL element may include an arbitrary member (for example, a hole injection layer, a hole transport layer, an electron injection layer, and / or an electron transport layer) at any appropriate position.

  When an organic EL cell is used as the image display cell, the polarizing plate in the image display device is usually not essential. However, since the thickness of the organic light emitting layer is as thin as about 10 nm, external light is reflected by the metal electrode and emitted again to the viewing side, and when viewed from the outside, the display surface of the organic EL display device looks like a mirror surface There is a case. In order to shield such specular reflection of external light, it is preferable to provide a polarizing plate on the viewing side of the organic EL cell, and further provide a quarter wavelength plate between the organic EL cell and the polarizing plate. . By constructing a circularly polarizing plate by combining these viewing side polarizing plates and quarter-wave plates, external light reflected by the metal electrode of the organic EL cell is shielded by the circularly polarizing plate. A reduction in the visibility of the device can be suppressed.

  As the liquid crystal cell, any liquid crystal cell that can be used in a liquid crystal display device can be appropriately selected and used, and the method and structure thereof are not particularly limited. For example, a liquid crystal cell such as a VA mode, an IPS mode, a TN mode, an STN mode, or a bend alignment (π type) can be appropriately selected and used. Therefore, the liquid crystal cell can be used by appropriately selecting a known liquid crystal material and a liquid crystal made of a liquid crystal material that can be developed in the future. In one embodiment, a preferred liquid crystal cell is a transmissive liquid crystal cell.

<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 viewer-side protective film (viewer-side polarizer protective film) of the viewer-side polarizer may be any film conventionally used as a high retardation alignment film or a polarizer protective film, but is not limited thereto. is not.

  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. From the viewpoint of handling and availability, for example, a triacetyl cellulose (TAC) film, an acrylic film, a cyclic olefin-based film (for example, a norbornene-based film), a polypropylene film, a polyolefin-based film (for example, TPX), etc. It is preferable to use one or more films selected from the group consisting of:

  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 liquid crystal. For example, a resin in which a liquid crystal compound (for example, a discotic liquid crystal compound and / or a birefringent compound) is dispersed in triacetyl cellulose. , One selected from the group consisting of cyclic olefin resins (for example, norbornene resins), propionyl acetate resins, polycarbonate film resins, acrylic resins, styrene acrylonitrile copolymer resins, lactone ring-containing resins, and imide group-containing polyolefin resins. The thing obtained from the above 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” (manufactured by Fujifilm) for TN system, “Wideview-B” (manufactured 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 a base film, a rigid plate such as a high retardation alignment film or another film conventionally used as a base film or a glass plate can be used. When the image display device is a flexible display, the base film is preferably a transparent base material having flexibility, and for example, is preferably the following transparent resin film.

  Examples of other films conventionally used as the base film include various resin films having transparency. For example, polyester resin, acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth) acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate A film obtained from one or more kinds of resins selected from the group consisting of resins and polyphenylene sulfide resins 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) Base 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 of the present invention 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 preferably has one or more scattering prevention films. As the anti-scattering film, the above-described high retardation alignment film or various films conventionally used as an anti-scattering film (for example, the transparent resin film described for the base film) can also be used. When two or more anti-scattering films are provided, they may be formed of the same material or different.

  When the alignment film is used as an anti-scattering film for the surface cover plate of the image display device, the alignment film may be disposed on the light source side or the viewing side of the surface cover plate. Moreover, the laminated glass structure which laminated | stacked glass on the both sides of the oriented film may be sufficient. When the oriented film is on the light source side of the surface cover plate, it is preferable to provide an antireflection layer on the opposite side of the oriented film from the surface cover plate. A bright and clear image can be obtained by providing an antireflection layer.

  When using an oriented film as an anti-scattering film, it is preferable to impart an ultraviolet absorbing function to the oriented film. The imparting of the ultraviolet absorbing function can be performed by adding an ultraviolet absorber to the oriented film, or applying an ultraviolet absorbing coat on the viewing side of the oriented film. When the oriented film is on the viewing side of the front cover plate, it is preferable to provide an antireflection layer, an antiglare layer, an antistatic layer, an antifouling layer, etc. on the opposite side of the oriented film from the front cover plate. In this case, an antireflection layer may be provided on the light source side of the outermost surface cover plate, or may be bonded to another member on the viewing side with an adhesive.

  The polarizer protective film, the base film, and the scattering prevention 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.

  The oriented film may have various functional layers. Examples of such a functional layer include a hard coat layer, an antiglare layer, an antireflection layer, a low reflection layer, a low reflection antiglare layer, an antireflection antiglare layer, an antistatic layer, a silicone layer, an adhesive layer, and an antifouling layer. One or more selected from the group consisting of a layer, a water repellent layer, a blue cut layer and the like can be used. By providing these layers, an effect of improving color spots when observed from an oblique direction can be expected.

  When providing various functional layers, it is preferable to have an easy-adhesion layer on the surface of the oriented film. At that time, from the viewpoint of suppressing interference due to reflected light, it is preferable to adjust the refractive index of the easy-adhesion layer so that it is close to the geometric mean of the refractive index of the functional layer and the refractive index of the alignment film. The refractive index of the easy-adhesion layer can be adjusted by a known method. For example, the refractive index of the easy-adhesion layer can be easily adjusted by adding titanium, zirconium, or other metal species to the binder resin.

(Hard coat layer)
The hard coat layer only needs to be a layer having hardness and transparency. Usually, various curable properties such as an ionizing radiation curable resin typically cured by ultraviolet rays or an electron beam, and a thermosetting resin cured by heat. What was formed as a cured resin layer of resin is used. In order to appropriately add flexibility and other physical properties to these curable resins, thermoplastic resins and the like may be added as appropriate. Among the curable resins, ionizing radiation curable resins are preferable because they are representative and an excellent hard coating film can be obtained.

  As the ionizing radiation curable resin, a conventionally known resin may be appropriately employed. As the ionizing radiation curable resin, a radical polymerizable compound having an ethylenic double bond, a cationic polymerizable compound such as an epoxy compound, and the like are typically used. These compounds include monomers, oligomers, prepolymers, and the like. These can be used alone or in appropriate combination of two or more. Typical compounds are various (meth) acrylate compounds that are radical polymerizable compounds. Among the (meth) acrylate compounds, compounds used at a relatively low molecular weight include, for example, polyester (meth) acrylate, polyether (meth) acrylate, acrylic (meth) acrylate, epoxy (meth) acrylate, urethane (meth) ) Acrylate, etc.

  Examples of the monomer include monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone; or, for example, trimethylolpropane tri (meth) acrylate, tripropylene glycol di (Meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, etc. These polyfunctional monomers are also used as appropriate. (Meth) acrylate means acrylate or methacrylate.

  When the ionizing radiation curable resin is cured with an electron beam, a photopolymerization initiator is unnecessary, but when it is cured with ultraviolet rays, a known photopolymerization initiator is used. For example, in the case of a radical polymerization system, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, or the like can be used alone or in combination as a photopolymerization initiator. In the case of a cationic polymerization system, an aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt, metatheron compound, benzoin sulfonate, or the like can be used alone or in combination as a photopolymerization initiator.

  The thickness of the hard coat layer may be an appropriate thickness, for example, 0.1 to 100 μm, but usually 1 to 30 μm. The hard coat layer can be formed by appropriately adopting various known coating methods.

  A thermoplastic resin, a thermosetting resin, or the like can be appropriately added to the ionizing radiation curable resin for the purpose of adjusting the physical properties as appropriate. Examples of the thermoplastic resin or thermosetting resin include an acrylic resin, a urethane resin, and a polyester resin, respectively.

  In order to impart light resistance to the hard coat layer and prevent discoloration, strength deterioration, cracking, and the like due to ultraviolet rays contained in sunlight, it is also preferable to add an ultraviolet absorber in the ionizing radiation curable resin. When an ultraviolet absorber is added, the ionizing radiation curable resin is preferably cured with an electron beam in order to reliably prevent the ultraviolet coater from inhibiting the curing of the hard coat layer. Examples of the ultraviolet absorber include organic ultraviolet absorbers such as benzotriazole compounds and benzophenone compounds, or inorganic ultraviolet absorbers such as fine particles of zinc oxide, titanium oxide, and cerium oxide having a particle size of 0.2 μm or less, What is necessary is just to select and use from well-known things. The addition amount of the ultraviolet absorber is about 0.01 to 5% by mass in the ionizing radiation curable resin composition. In order to further improve the light resistance, it is preferable to add a radical scavenger such as a hindered amine radical scavenger in combination with an ultraviolet absorber. In addition, the electron beam irradiation has an acceleration voltage of 70 kV to 1 MV and an irradiation dose of about 5 to 100 kGy (0.5 to 10 Mrad).

(Anti-glare layer)
As the antiglare layer, a conventionally known layer may be appropriately employed, and it is generally formed as a layer in which an antiglare agent is dispersed in a resin. As the antiglare agent, inorganic or organic fine particles are used. These fine particles have a spherical shape, an elliptical shape, or the like. The fine particles are preferably transparent. Examples of such fine particles include silica beads as inorganic fine particles and resin beads as organic fine particles. Examples of the resin beads include styrene beads, melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, and benzoguanamine-formaldehyde beads. The fine particles are usually added in an amount of 2 to 30 parts by mass, preferably about 10 to 25 parts by mass with respect to 100 parts by mass of the resin.

  The above resin for dispersing and holding the antiglare agent is preferably as hard as possible as in the hard coat layer. Therefore, as the resin, for example, a curable resin such as an ionizing radiation curable resin or a thermosetting resin described in the hard coat layer can be used.

  The thickness of the antiglare layer may be an appropriate thickness, and is usually about 1 to 20 μm. The antiglare layer can be formed by appropriately adopting various known coating methods. In addition, it is preferable to add well-known anti-settling agents such as silica to the coating liquid for forming the anti-glare layer in order to prevent precipitation of the anti-glare agent.

(Antireflection layer)
As the antireflection layer, a conventionally known layer may be appropriately employed. In general, the antireflection layer is composed of at least a low refractive index layer, and a low refractive index layer and a high refractive index layer (having a higher refractive index than the low refractive index layer) are alternately stacked adjacent to each other and the surface side has a low refractive index. It consists of multiple layers as the rate layer. Each thickness of the low-refractive index layer and the high-refractive index layer may be an appropriate thickness according to the application, and is about 0.1 μm when adjacent layers are stacked, and about 0.1 to 1 μm when the low-refractive index layer alone is used. It is preferable.

  As a low refractive index layer, a layer containing a low refractive index material such as silica or magnesium fluoride in a resin, a layer of a low refractive index resin such as a fluorine-based resin, or a low refractive index material in a low refractive index resin A thin film formed by a thin film forming method (for example, physical or chemical vapor deposition such as vapor deposition, sputtering, CVD, or the like), an oxidation layer, or a layer made of a low refractive index material such as silica or magnesium fluoride. Examples thereof include a film formed by a sol-gel method in which a silicon oxide gel film is formed from a silicon sol solution, or a layer in which void-containing fine particles are contained in a resin as a low refractive index substance.

  The void-containing fine particles are fine particles containing gas inside, fine particles having a porous structure containing gas, etc., and with respect to the original refractive index of the fine particle solid portion, It means fine particles whose refractive index is apparently lowered. Examples of such void-containing fine particles include silica fine particles disclosed in JP-A No. 2001-233611. Examples of the void-containing fine particles include hollow polymer fine particles disclosed in JP-A No. 2002-805031, in addition to inorganic substances such as silica. The particle diameter of the void-containing fine particles is, for example, about 5 to 300 nm.

  As the high refractive index layer, a layer containing a high refractive index material such as titanium oxide, zirconium oxide or zinc oxide in a resin, a layer of a high refractive index resin such as a fluorine-free resin, or a high refractive index material is highly refracted. A layer formed of a high-refractive-index material such as titanium oxide, zirconium oxide, or zinc oxide in a thin film forming method (for example, vapor deposition, sputtering, CVD, etc., physical or chemical vapor deposition) Method).

(Antistatic layer)
As the antistatic layer, a conventionally known layer may be employed as appropriate, and it is generally formed as a layer containing an antistatic layer in a resin. As the antistatic layer, an organic or inorganic compound is used. For example, examples of the antistatic layer of an organic compound include a cationic antistatic agent, an anionic antistatic agent, an amphoteric antistatic agent, a nonionic antistatic agent, and an organometallic antistatic agent. The inhibitor is used not only as a low molecular compound but also as a high molecular compound. As the antistatic agent, conductive polymers such as polythiophene and polyaniline are also used. Further, as the antistatic agent, for example, conductive fine particles made of a metal oxide are used. The particle diameter of the conductive fine particles is, for example, about 0.1 nm to 0.1 μm in average particle diameter in terms of transparency. Examples of the metal oxide include ZnO, CeO ₂ , Sb ₂ O ₂ , SnO ₂ , ITO (indium doped tin oxide), In ₂ O ₃ , Al ₂ O ₃ , ATO (antimony doped tin oxide), AZO (aluminum doped zinc oxide) etc. are mentioned.

  Examples of the resin containing the antistatic layer include curable resins such as ionizing radiation curable resins and thermosetting resins as described in the hard coat layer. When the layer is formed as a layer and the surface strength of the antistatic layer itself is unnecessary, a thermoplastic resin or the like is also used. The thickness of the antistatic layer may be set appropriately, and is usually about 0.01 to 5 μm. The antistatic layer can be formed by appropriately adopting various known coating methods.

  When using an oriented film as a polarizer protective film, it is preferable to provide an antistatic layer on the surface layer. When laminating the antistatic layer, it is preferable to laminate the antistatic layer and the antiglare layer on top of each other, or add an antistatic agent to the antiglare layer and laminate a layer that combines both layers. When assembling the image display device, a polarizing plate protective film (a member that is not incorporated in the liquid crystal display device and discarded in the manufacturing process) is usually used as a process member on the surface of the polarizing plate. It is preferable to provide an antistatic layer on the side where the polarizing plate protective film is in contact with the polarizing plate or on the opposite side.

(Anti-fouling layer)
As the antifouling layer, a conventionally known layer may be appropriately employed. Generally, in the resin, a silicon compound such as silicone oil or silicone resin; a fluorine compound such as fluorine surfactant or fluorine resin. It can be formed by a known coating method using a paint containing a stain-proofing agent such as wax. The thickness of the antifouling layer may be set appropriately, and can usually be about 1 to 10 μm.

  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.

Test Example 1: Evaluation of rainbow spots In an image display device having the following configuration, a polarizing film was placed on the viewing side surface so as to be parallel to the viewing side surface, and a white screen was displayed. While maintaining the parallel state, the angle formed by the polarization axis of the polarizing film and the polarization axis of the viewing-side polarizer of the image display device is rotated 360 degrees, and a white image is viewed to confirm the presence and extent of rainbow spots. Evaluation was made according to the following criteria.

<Evaluation criteria>
○: When observed from the front, no rainbow spots are observed and the visibility is good.
X: When observed from the front, rainbow spots are observed.

<Configuration of image display device>
(1) Backlight light source: white LED or cold cathode tube (2) Light source side polarizing plate: TAC film is provided as a protective film on both sides of a polarizer made of PVA and iodine.
(3) Image display cell: Liquid crystal cell (4) Viewing-side polarizing plate: Polarizing plate (tape film with a thickness of 80 μm manufactured by Fuji Film Co., Ltd.) as a protective film on both sides of a polarizer made of PVA and iodine ( 5) Visual side scattering prevention film (front protective film): the following oriented films 1 to 5

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).)

Oriented film 1
After drying at reduced pressure (1 Torr) for 6 hours at 135 ° C. without containing particles, the PET (A) resin pellets were 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.

  The unstretched film was guided to a tenter stretching machine and 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 3% relaxation treatment in the width direction to obtain a uniaxially oriented film 1 having a film thickness of about 200 μm. It was. Re of the oriented film 1 was 20500 nm.

Oriented film 2
By changing the thickness of the unstretched film, a uniaxially oriented oriented film 2 was obtained in the same manner as the oriented film 1 except that the thickness of the film was about 300 μm. Re of the oriented film 2 was 31000 nm.

Oriented film 3
A uniaxially oriented alignment film 3 was obtained in the same manner as the alignment film 1 except that the thickness of the unstretched film was changed to about 400 μm. Re of the oriented film 3 was 40500 nm.

Oriented film 4
By changing the thickness of the unstretched film, a uniaxially oriented oriented film 4 was obtained in the same manner as the oriented film 1 except that the thickness of the film was about 500 μm. Re of the oriented film 4 was 51000 nm.

Oriented film 5
A uniaxially oriented alignment film 5 was obtained in the same manner as the alignment film 1 except that the thickness of the unstretched film was changed to about 20 μm. Re of the oriented film 5 was 1900 nm.

  The retardation (Re) was 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).

  The evaluation results are shown in Table 1 below.

  As shown in Table 1 above, it was confirmed that by disposing a high retardation alignment film on the viewer side from the polarizer, deterioration in image quality due to color tone disturbance such as rainbow spots can be suppressed.

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 substrate film E11b Transparent conductive layer E12 Viewing side transparent conductive film E12a Viewing side substrate film E12b Transparent conductive layer E13 Spacer E14 Light source side scattering prevention film E15 Viewing side scattering prevention film 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 protective film L10b Polarizer protective film L10b View Side polarizer protective film L11 Light source side transparent conductive film L11a Light 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 scattering prevention film L15 Viewing side Anti-scattering film E17 Substrate E18 Anode E19 Organic light emitting layer E20 Cathode

Claims (3)

(1) Image display cell,
(2) A polarizer disposed on the viewer side from the image display cell, and (3) a retardation having a thickness of 200 μm or more and 500 μm or less and 3000 nm or more and 150,000 nm or less disposed on the viewer side of the polarizer. An image display device having an alignment film. 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 device is a flexible image display device.

Images