JP6521149B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device.

  Image display devices are widely put to practical use in mobile phones, tablet terminals, personal computers, televisions, PDAs, electronic dictionaries, car navigation systems, music players, digital cameras, digital video cameras and the like. The use of the image display apparatus is no longer limited to offices and indoors with the progress of downsizing and weight reduction of the image display apparatus, and the use outdoors while traveling on a car or a train is also expanding.

  Under such circumstances, opportunities for visualizing an image display device through a polarizing filter such as sunglasses are increasing. In connection with the use of such an image display device, Patent Document 1 discloses a screen through a polarizing plate when a polymer film having a retardation of less than 3000 nm is used on the viewing side of the polarizing plate on the viewing side of the liquid crystal display device. It has been reported that a strong interference color appears when observing. And as a means to solve the said problem, patent document 1 is describing that the retardation of the polymer film used for visual recognition sides from the polarizing plate on the visual recognition side shall be 3000-30000 nm.

WO2011 / 058774

  As described above, in Patent Document 1, when the liquid crystal display device is viewed in sunglasses by controlling the retardation of the polymer film used on the viewing side of the liquid crystal display device on the viewing side to 3000 to 30000 nm. It is described to eliminate the appearance of the interference color of. That is, Patent Document 1 describes that the appearance of interference color is eliminated by replacing the alignment film on the viewing side with respect to the polarizing plate on the viewing side with an alignment film having a specific retardation. However, many of the currently distributed films have a retardation value of less than 3000 nm, and the method has a problem that such films can not be used for an image display device. Therefore, the present invention enables the use of a general-purpose oriented film having a retardation value of less than 3000 nm, while using the interference color (i.e., iridescence) when viewed through a polarizing film such as sunglasses. Aim to improve the

  The present inventors repeated day-and-night research in order to solve the above problems, and it was found that by combining an alignment film whose retardation is not particularly controlled and an alignment film whose retardation is controlled to 3000 nm or more and 150000 nm or less I found that a solution was possible. Then, the present inventors adopt an orientation film in which retardation is not controlled as a light source side scattering prevention film of the image display device, and an orientation film having retardation of 3000 nm or more and 150000 nm or less as a base film. It reached. The present inventors have made further studies and improvements based on such findings to complete the present invention.

The representative invention is as follows.
Item 1.
(1) White light source having continuous emission spectrum,
(2) Image display cell,
(3) A polarizer disposed closer to the viewer than the image display cell
(4) a shatterproof film disposed closer to the visual side than the polarizer, and (5) a base film on which a transparent conductive layer is disposed closer to the visual side than the shatterproof film,
The anti-scattering film is an oriented film,
The base film is an oriented film having a retardation of 3000 nm or more and 150000 nm or less.
Image display device.
Item 2.
Item 2. The image display device according to item 1, wherein the substrate film is disposed such that the alignment main axis thereof is 45 degrees with respect to the polarization axis of the polarizer.
Item 3.
Item 3. The image display device according to item 1 or 2, wherein the anti-scattering film is disposed such that the alignment main axis thereof and the polarization axis of the polarizer are substantially perpendicular or substantially parallel.
Item 4.
The image display device according to any one of Items 1 to 3, wherein a ratio (Re / Rth) of retardation (Re) to retardation in a thickness direction (Rth) of the base film is 0.2 or more and 1.2 or less. .
Item 5.
Item 5. The image display device according to any one of Items 1 to 4, wherein the white light source having a continuous emission spectrum is a white light emitting diode.

  According to the present invention, the visibility of the image display device is improved. In particular, the reduction in image quality represented by rainbow marks that occurs when viewed through a polarizing filter is reduced. In the present specification, "rainbow spot" is a concept including "color spot", "color shift" and "interference color".

It is a typical schematic diagram of the image display apparatus provided with the touch panel. It is a chart which shows the visibility measured about the case where the angle which the polarization axis of the visual recognition side polarizer and the polarization axis of a polarization filter form is 0 degree. In FIG. 2, (I) to (IV) are as follows: (I) no rainbow spots are seen (II) thin rainbow spots are visible, (III) clear rainbow spots are visible, (IV) ) The screen looks dark due to the decrease in luminance. It is a chart which shows the visibility measured about the case where the angle which the polarization axis of a visual recognition side polarizer and the polarization axis of a polarization filter form is 90 degrees. In FIG. 3, (I) to (IV) are as follows: (I) no rainbow spots are seen (II) thin rainbow spots are visible, (III) clear rainbow spots are visible, (IV) ) The screen looks dark due to the decrease in luminance. It is a chart which shows the visibility measured about the case where the angle which the polarization axis of a visual recognition side polarizer and the polarization axis of a polarization filter form is 45 degrees. In FIG. 4, (I) to (IV) are as follows: (I) no rainbow spots are seen (II) thin rainbow spots are visible, (III) clear rainbow spots are visible, (IV) ) The screen looks dark due to the decrease in luminance.

  The image display device typically has an image display cell and a polarizing plate. A liquid crystal cell or an organic EL cell is typically used for the image display cell. A representative schematic view of an image display apparatus using a liquid crystal cell as the image display cell is shown in FIG.

  The liquid crystal display device (1) has a light source (2), a liquid crystal cell (4), and a touch panel (6) as a functional layer. Here, in this document, the side on which the image of the liquid crystal display device is displayed (the side on which the human views the image) is referred to as the “viewing side”, and the side opposite to the viewing side (that is, in the liquid crystal display device, usually back light) The side on which a light source called a light source is set is referred to as the “light source side”. In FIG. 1, the right side is the viewing side, and the left side is the light source side.

  Polarizers (a light source-side polarizer (3) and a viewer-side polarizer (5)) are provided on both the light source side and the viewer side of the liquid crystal cell (4). Each polarizing plate (3, 5) typically has a structure in which polarizer protective films (9a, 9b, 10a, 10b) are laminated on both sides of a film called polarizers (7, 8). The image display device (1) of FIG. 1 is provided with a touch panel (6) as a functional layer on the viewing side with respect to the viewing side polarizing plate (5). The touch panel shown in FIG. 1 is a resistive touch panel. The touch panel (6) has a structure in which two transparent conductive films (11, 12) are disposed via a spacer (13). The transparent conductive films (11, 12) are obtained by laminating the base films (11a, 12a) and the transparent conductive layers (11b, 12b). Moreover, the scattering prevention film (14, 15) which is a transparent substrate is provided in the light source side and visual recognition side of a touch panel (6) through an adhesive layer.

  In addition, in FIG. 1, although the touch panel (6) was described as a functional layer provided in the visual recognition side of the visual recognition side polarizing plate (5), it is not limited to a touch panel, What is a layer which has a film It may be a layer. Moreover, although the resistive film type touch panel was described as a touch panel, it is also possible to use the touch panel of other types, such as a projection type electrostatic capacitance type. The touch panel in FIG. 1 has a structure having two transparent conductive films, but the structure of the touch panel is not limited to this. For example, the number of the transparent conductive film and / or the shatterproof film is one. Good. In the liquid crystal display device (1), the anti-scattering film does not necessarily have to be disposed on both sides of the touch panel (6), but may be disposed on either one side or the anti-scattering film is not disposed on both sides It may be a configuration. The shatterproof film may be disposed on the touch panel via the adhesive layer, or may be disposed on the touch panel without the adhesive layer.

<Positional relationship of oriented film>
Oriented films may be used for image display devices for various purposes. In the present specification, the oriented film means a polymer film having birefringence. In the liquid crystal display device of FIG. 1, the oriented film is typically a film on the viewing side of the polarizer (8) (hereinafter referred to as “the viewing side polarizer”) located on the viewing side of the liquid crystal cell (4) That is, a polarizer protective film (10b) (hereinafter referred to as "visible side polarizer protective film") located on the viewing side from the viewing side polarizer (8), a transparent conductive film (11) located on the light source side from the spacer (13) Substrate film (11a) (hereinafter referred to as "light source side substrate film"), a substrate film (12a) of a transparent conductive film (12) located on the viewing side from the spacer (13) (hereinafter referred to as Anti-scattering film (14) (hereinafter referred to as "light-source-side anti-scattering film") which is between the visible-side polarizer protective film (10b) and the light source-side base film (11a) And shatterproof film (15) on the viewing side from the visible side substrate film 12a (hereinafter, referred to as "viewing side shatterproof film") may be used.

The image display apparatus includes an alignment film as a light source side scattering prevention film (14), and an alignment film having a retardation of 3000 nm or more and 150,000 nm or less as a light source side base film (11a) and / or a viewing side base film (12a). It is preferable to have. In this specification, an oriented film having a retardation of 3000 nm or more and 150000 nm or less is referred to as a "high retardation oriented film". The retardation of the oriented film used as the light source side shatterproof film (14) is not particularly limited, but is preferably less than 3000 nm. In this document, an oriented film having a retardation of less than 3000 nm is referred to as a "low retardation oriented film".

  It is assumed that the angle (the low retardation alignment film and the polarizer are in the same plane) formed by the alignment main axis of the low retardation alignment film and the polarization axis of the viewing side polarizer (axis parallel to the vibration direction of the outgoing polarized light). Is optional, but from the viewpoint of reducing rainbow marks, it is preferable that the angles are substantially parallel or perpendicular. From such a point of view, the angle is preferably 0 degrees or 90 degrees ± 5 degrees or less, preferably 0 degrees or 90 degrees ± 4 degrees or less, and preferably 0 degrees or 90 degrees ± 3 degrees or less It is preferably 0 degrees or 90 degrees ± 2 degrees or less, preferably 0 degrees or 90 degrees ± 1 degrees or less, preferably 0 degrees or 90 degrees. Here, the term "below" applies only to the next numerical value of "±".

  On the other hand, when producing an oriented film industrially, it is difficult to align the direction of the orientation main axis across the entire film, such as the end and center of the film due to the bowing phenomenon etc. Control in parallel or perpendicular to the polarization axis of the viewing side polarizer is not necessarily preferable from the viewpoint of production efficiency. On the other hand, as described above, by combining with the high retardation alignment film, even if the alignment main axis of the low retardation alignment film and the polarization axis of the viewing side polarizing plate are not completely parallel, the occurrence of iridescence occurs. Is suppressed. Therefore, in consideration of these circumstances comprehensively, in one embodiment, an angle formed by the alignment main axis of the low retardation alignment film and the polarization axis of the viewing side polarizer (the low retardation alignment film and the polarizer are in the same plane) It is preferred that the upper side is slightly off parallel or perpendicular). Based on the parallel or vertical state (0 degree), the deviation of the angle is preferably 1 degree or more, preferably 2 degrees or more, preferably 3 degrees or more, preferably 4 degrees or more, preferably 5 degrees or more as the lower limit. The upper limit is preferably 45 degrees or less, preferably 44 degrees or less, preferably 43 degrees or less, preferably 42 degrees or less, preferably 41 degrees or less, preferably 40 degrees or less. These upper and lower limits can be arbitrarily combined.

  As described above, when the angle formed by the alignment main axis of the low retardation alignment film and the polarization axis of the viewing side polarizer is not completely parallel or perpendicular, the polarization axis of the polarizing filter such as polarizing sunglasses and the viewing side polarizer When the polarization axis is parallel or perpendicular, a preferable image in which rainbow spots are more suppressed can be viewed. Therefore, in such a case, in consideration of the polarization axis when a polarization filter such as polarization sunglasses is usually used, the polarization axis of the viewing side polarizer and the polarization axis of the polarization filter are parallel or perpendicular to each other. Preferably, the child is arranged in the image display device.

  The angle formed by the orientation main axis of the high retardation orientation film and the polarization axis of the viewing side polarizer (assuming that the high retardation orientation film and the polarizer are in the same plane) is not particularly limited, but it reduces iridescence It is preferable that the angle is close to 45 degrees from the viewpoint of For example, the angle is 45 degrees ± 20 degrees or less, preferably 45 degrees ± 15 degrees or less, preferably 45 degrees ± 10 degrees or less, preferably 45 degrees ± 5 degrees or less, preferably 45 degrees ± 3 degrees or less, 45 degrees ± 2 degrees or less, 45 degrees ± 1 degrees or less, 45 degrees. As used herein, the term "below" means that it only applies to the next value of "±". Therefore, for example, the term "45 degrees ± 20 degrees or less" means that fluctuations in the range of 20 degrees above and below around 45 degrees are allowed.

  Arranging the high retardation alignment film so as to satisfy the above conditions can be achieved, for example, by arranging the cut high retardation alignment film so that the alignment main axis is at a specific angle with the polarization axis of the polarizer, or It can be carried out by a method in which the high retardation alignment film is obliquely stretched to be at a specific angle with the polarization axis of the polarizer.

In one embodiment, the angle formed by the alignment main axis of the low retardation alignment film and the high retardation alignment film is preferably substantially parallel or substantially perpendicular from the viewpoint of rainbow mark suppression.

  The image display device may have two or more high retardation alignment films. When the image display apparatus includes two or more high retardation alignment films, the position at which the remaining high retardation alignment films are provided as long as at least one high retardation alignment film is used as a base film on the light source side or the viewing side. Is not particularly limited. When two high retardation alignment films are both provided on the viewing side of the low retardation alignment film, it is preferable that the alignment main axes of the two high retardation alignment films be close to each other in parallel. For example, the angle formed by the alignment main axes of two high retardation alignment films (assuming that the two high retardation alignment films are in the same plane) is preferably 0 ° ± 15 ° or less, preferably 0 ° ± 10 degrees or less, preferably 0 degrees ± 5 degrees or less, preferably 0 degrees ± 3 degrees or less, preferably 0 degrees ± 2 degrees or less, preferably 0 degrees ± 1 degrees or less, preferably 0 degrees. When the angle deviates from substantially 0 degree, it is preferable to provide a retardation difference of at least 1800 nm, preferably at least 2500 nm, preferably at least 3500 nm, preferably at least 4000 nm to the two high retardation alignment films.

  The image display device may be provided with two or more low retardation alignment films. When the image display device includes two or more low retardation alignment films, the position at which the remaining low retardation alignment films are provided is not particularly limited as long as at least one low retardation alignment film is used as a light source side shatterproof film. When two low retardation alignment films are both provided on the light source side with respect to the high retardation alignment film, the low retardation alignment film on the most light source side has the alignment main axis and the polarization axis of the viewing side polarizer as described above. It is preferable to arrange so that the angle to form may become small. On the other hand, the direction in which another low retardation alignment film provided between the low retardation alignment film closest to the light source and the high retardation alignment film is provided is not particularly limited.

  When viewing an image display device using a polarizing filter from the viewpoint of obtaining better visibility by avoiding rainbow marks and the like, the polarization axis of the polarizing filter and the polarizer on the viewer side (and the light source side polarizer) It is preferable that the angle formed with the polarization axis (assuming that the polarizing filter and the polarizer are in the same plane) is substantially parallel or substantially perpendicular. Here, “substantially parallel or substantially perpendicular” means 0 degree or 90 degrees ± 10 degrees or less, preferably 0 degrees or 90 degrees ± 5 degrees or less, preferably 0 degrees or 90 degrees ± 4 degrees or less It is preferably 0 ° or 90 ° ± 3 ° or less, preferably 0 ° or 90 ° ± 2 ° or less, and preferably 0 ° or 90 ° ± 1 ° or less. Polarization filters, such as polarization sunglasses, are usually designed such that the polarization axis when worn is perpendicular to the horizontal. Therefore, from the viewpoint of obtaining more excellent visibility when looking at the image display device through such a polarizing filter, in the image display device, the polarizer has a rectangular shape with the vertical axis or horizontal axis of the rectangular display. It is preferable to arrange so that it may become parallel.

  The orientation main axis of the high retardation orientation film is preferably arranged in the image display device so as to be parallel to the vertical axis or horizontal axis of the display screen which is rectangular. When the orientation main axis of the high retardation orientation film is substantially parallel to the longitudinal axis of the display, rainbow spots are suppressed and visibility is excellent even when the screen is observed not from the front but from an oblique direction (lateral direction). is there. On the other hand, when the orientation main axis of the high retardation orientation 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 not from the front but from an oblique direction (longitudinal direction). It is for.

<Retardation of oriented film>
The retardation of the high retardation alignment film is preferably 3000 nm or more and 150000 nm or less from the viewpoint of reducing rainbow marks. The lower limit value of the retardation of the high retardation alignment film is preferably 4500 nm or more, preferably 6000 nm or more, preferably 8000 nm or more, preferably 10000 nm or more. On the other hand, the upper limit of the retardation of the high retardation alignment film is substantially no improvement in the visibility even if a polyester film having a retardation higher than that is used, and the orientation according to the retardation height is Since the thickness of the film also tends to rise, it is set to 150000 nm from the viewpoint of not being in contradiction to the demand for thinning, but it can be set to a still higher value. When the image display device has two or more high retardation oriented films, their retardations may be the same or different.

  From the viewpoint of more effectively suppressing rainbow marks, the high retardation alignment film preferably has a ratio (Re / Rth) of retardation (Re) to retardation in the thickness direction (Rth) of 0.2 or more, Preferably it is 0.5 or more, preferably 0.6 or more. The retardation in the thickness direction means an average value of retardations obtained by multiplying the two birefringence ΔNxz and ΔNyz respectively by the film thickness d when viewed from the cross section in the film thickness direction. As Re / Rth is larger, the action of birefringence is more isotropic, and the occurrence of rainbow marks on the screen can be suppressed more effectively. In addition, in this document, when only describing as "retardation", it means in-plane retardation.

  Although the maximum value of Re / Rth is 2.0 (that is, a perfect uniaxial symmetry film), the mechanical strength in the direction orthogonal 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, 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, about 120 degrees up and down) required for the image display device.

  The retardation of the low retardation alignment film is not particularly limited as long as it is less than 3000 nm. The lower limit value of the retardation of the low retardation alignment film suitably used in the present invention is 50 nm or more, 100 nm or more, 200 nm or more, 300 nm or more, 400 nm or more, from the viewpoint that iridescence may occur when it is used alone. Or 500 nm or more. In terms of effectively improving rainbow marks, it is preferably 800 nm or more, preferably 1000 nm or more, preferably 1300 nm or more. In addition, the upper limit of the retardation of the low retardation alignment film is less than 3000 nm, less than 2500 nm, or less than 2300 nm from the viewpoint that suppression of rainbow marks is possible in combination with the high retardation alignment film. When the image display device has two or more low retardation alignment films, the retardations thereof may be the same or different.

  The low retardation oriented film may be a uniaxially stretched oriented film or a biaxially stretched oriented film, but is preferably a biaxially stretched oriented film from the viewpoint of reducing the tearability of the film.

  The retardation of the oriented film can be measured according to a known method. Specifically, the refractive index and thickness in the biaxial direction can be measured and determined. It can also be determined using a commercially available automatic birefringence measuring device (for example, KOBRA-21ADH: manufactured by Oji Scientific Instruments).

The high retardation alignment film can be produced by appropriately selecting a known method. For example, a high retardation alignment film may be a polyester resin, a polycarbonate resin, a polystyrene resin, a syndiotactic polystyrene resin, a polyetheretherketone resin, a polyphenylene sulfide resin, a cycloolefin resin, a liquid crystalline polymer resin, and a cellulose resin to a liquid crystal compound. It can manufacture using 1 or more types selected from the group which consists of added resin. Therefore, the liquid crystal compound is added to the polyester film, the polycarbonate film, the polystyrene film, the syndiotactic polystyrene film, the polyetheretherketone film, the polyphenylene sulfide film, the cycloolefin film, the liquid crystalline film, and the cellulose resin in the high retardation alignment film. Film.

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

  The low retardation alignment film can be manufactured by appropriately selecting a known method. For example, the low retardation oriented film is made of polyester resin, acetate resin, polyether sulfone resin, polycarbonate resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin (polyethylene resin, polypropylene resin, cyclic polyolefin etc.), (meth) acrylic resin, polychlorinated A resin selected from the group consisting of vinyl resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin, cellulose acetate resin (triacetyl cellulose etc.) and the like can be obtained as a raw material. Among these, polyester resins and polyolefin resins are preferable, preferably polyester resins, and more preferably polyethylene terephthalate and / or polypropylene resins.

<Method of producing oriented film>
Below, a polyester film is taken as an example and the manufacturing method of the oriented film containing a high retardation oriented film and a low retardation oriented film is demonstrated. A polyester film can be obtained by condensing any dicarboxylic acid and diol. Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenyl carbonic acid Acid, diphenoxy ethane dicarboxylic acid, diphenyl sulfone carboxylic acid, anthracene dicarboxylic acid, 1,3-cyclopentane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid Acid, malonic acid, dimethyl malonic acid, succinic acid, 3, 3-diethyl succinic acid, glutaric acid, 2, 2- dimethyl glutaric acid, adipic acid, 2-methyl adipic acid, trimethyl adipic 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 etc. can be mentioned.

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 and the like, preferably polyethylene terephthalate and polyethylene naphthalate, preferably polyethylene terephthalate. . The polyester resin may contain other copolymerization components. From the viewpoint of mechanical strength, the proportion of the copolymerization components is preferably 3 mol% or less, preferably 2 mol% or less, more preferably 1.5 mol% or less . These resins are excellent in transparency and also excellent in thermal and mechanical properties. Moreover, these resins can control retardation easily by extending | stretching processing.

  The polyester film can be obtained according to a general production method. Specifically, the polyester resin is melted, and the non-oriented polyester extruded into a sheet is stretched in the longitudinal direction at a temperature higher than the glass transition temperature using the speed difference of the rolls, and then in the transverse direction by the 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 alignment film may be stretched at an oblique angle of 45 degrees.

  The production 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 stretching ratio is usually 1.0 to 3.5, preferably 1.0 to 3.0. Also, the transverse stretching ratio is usually 2.5 to 6.0 times, preferably 3.0 to 5.5 times.

  Controlling the retardation to a specific range can be performed by appropriately setting the stretching ratio, the stretching temperature, and the thickness of the film. For example, the higher the difference in draw ratio between longitudinal drawing and transverse drawing, the lower the drawing temperature, and the thicker the film, the easier it is to obtain high retardation. Conversely, the lower the stretching ratio difference between longitudinal stretching and transverse stretching, the higher the stretching temperature, and the thinner the film thickness, the easier it is to obtain lower retardation. In addition, as the stretching temperature is higher and the total stretching ratio is lower, it is easier to obtain a film having a low ratio of retardation to retardation in the thickness direction (Re / Rth). Conversely, the lower the stretching temperature, the higher the total stretching ratio, the higher the ratio of retardation to thickness direction retardation (Re / Rth). Furthermore, as for the heat processing temperature, normally 140-240 degreeC is preferable, Preferably it is 180-240 degreeC.

  In order to suppress the fluctuation of retardation in the polyester film, it is preferable that the thickness unevenness of the film be small. If the longitudinal stretching ratio is reduced to give a retardation difference, the value of the longitudinal thickness unevenness may increase. Since there is a region in which the value of the longitudinal thickness unevenness becomes very high in a certain 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 Is particularly preferred. The thickness unevenness of the film can be measured by any means. For example, a continuous tape-like sample (3 m in length) is collected in the film flow direction, and a commercially available measuring instrument (e.g., an electronic micrometer Millitron 1240 manufactured by Seiko I.M.) is used. The thickness of the point is measured, and 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 equation.
Thickness unevenness (%) = ((dmax-dmin) / d) x 100

<Image display cell and light source>
The image display device can typically include a liquid crystal cell or an organic EL cell as an image display cell. Moreover, it is preferable that the image display apparatus has a white light source having a continuous and wide emission spectrum from the viewpoint of suppressing rainbow marks. When the image display device includes a liquid crystal cell, the image display device preferably includes such a light source as a light source independent of the image display cell. On the other hand, in the case of the organic EL cell, since the organic EL cell itself has a function of a light source, it is preferable that the organic EL cell itself emits light having a continuous and wide emission spectrum. The type and structure of the light source having a continuous and broad emission spectrum are not particularly limited, and may be, for example, an edge light type or a direct type. By "continuous and broad emission spectrum" is meant an emission spectrum in which there is no wavelength range in which the light intensity is zero at least in the 450 to 650 nm wavelength range, preferably in the visible light range. 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.

  As a white light source which has a continuous and wide emission spectrum, a white light emitting diode (white LED) can be mentioned, for example. White LEDs include phosphors (that is, devices that emit white light by combining a blue light using compound semiconductor or a light emitting diode that emits ultraviolet light and a phosphor) and an organic light emitting diode (Organic light-emitting diode) : OLED etc. can be mentioned. From the point of view of continuous and broad emission spectrum and excellent luminous efficiency, white light comprising a light emitting element combining a blue light emitting diode using a compound semiconductor and an yttrium aluminum garnet yellow phosphor Light emitting diodes are preferred.

  As the liquid crystal cell, any liquid crystal cell that can be used in the liquid crystal display device can be appropriately selected and used, and the system or structure thereof is not particularly limited. For example, liquid crystal cells such as VA mode, IPS mode, TN mode, STN mode, and bend alignment (π type) can be appropriately selected and used. Therefore, the liquid crystal cell can appropriately select and use a liquid crystal produced from a known liquid crystal material and a liquid crystal material that can be developed in the future. A liquid crystal cell preferred in one embodiment is a transmissive liquid crystal cell.

  An organic EL cell can be used by appropriately selecting an organic EL cell known in the art. The organic EL cell is a light emitter (organic electroluminescent light emitter), and typically has a structure in which a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate. The organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of triphenylamine derivative etc. and a light emitting layer made of a fluorescent organic solid such as anthracene, and such A laminate of a light emitting layer and an electron injection layer comprising a perylene derivative or the like can be mentioned. As described above, since the organic EL cell has a function as an image display cell and a function as a light source, when the image display device includes the organic EL cell, an independent light source is not necessary. That is, the light source and the image display device in the image display device may be independent or integrated as long as their functions are exhibited.

  When using an organic EL cell as an image display cell, the polarizing plate in an image display apparatus is 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 looks like a mirror surface. It may be visible. In order to block such specular reflection of external light, it is preferable to provide a polarizing plate and a 1⁄4 wavelength plate on the viewing side of the organic EL cell. Therefore, when the image display device has an organic EL cell and a polarizing plate, the liquid crystal cell (4) in FIG. 1 is considered as an organic EL cell, and the viewing side polarizing plate (5) is considered as a polarizing plate. The positional relationship of the oriented film in the device (1) can be applied as it is.

<Polarizer and Polarizer Protective Film>
The polarizing plate has a structure in which both sides of a film-like polarizer are sandwiched by two protective films (sometimes referred to as "polarizer protective films"). As the polarizer, any polarizer (or polarizing film) used in the art can be appropriately selected and used. As a typical polarizer, although polyvinyl alcohol (PVA) film etc. which dyed dichroic materials, such as iodine, can be mentioned, it is not limited to this, and it is publicly known and developed from now on. The polarizer to be obtained can be appropriately selected and used.

  A commercially available product can be used as the PVA film, and for example, “KURALE VINYRON (manufactured by Kuraray Co., Ltd.)”, “TOCHERO VINYLON (manufactured by Higashi Cello Co., Ltd.),” (D.) Can be used, etc. Examples of the dichroic material include iodine, diazo compounds, polymethine dyes and the like.

  The polarizer can be obtained by any method, for example, uniaxially stretching a PVA film dyed with a dichroic material in a boric acid aqueous solution, and washing and drying while maintaining the stretched state It can be obtained by The stretching ratio of uniaxial stretching is usually about 4 to 8 but is not particularly limited. Other manufacturing conditions and the like can be appropriately set in accordance with a known method.

  The protective film on the viewer side of the viewer-side polarizer (viewer-side polarizer protective film) may be any film conventionally used as a high retardation alignment film, a low retardation alignment film, or a polarizer protective film. It is not limited.

  The type of the protective film on the light source side of the viewing side polarizer and the protective film on the light source side polarizer are arbitrary, and a film conventionally used as a protective film can be appropriately selected and used. From the viewpoint of handleability and availability, for example, triacetyl cellulose (TAC) film, acrylic film, cyclic olefin film (eg, norbornene film), polypropylene film, polyolefin film (eg, TPX), etc. It is preferred to use one or more non-birefringent films selected from the group consisting of

  In one embodiment, the light source side protective film of the visible side polarizer and the visible side protective film of the light source side polarizer are preferably an optical compensation film having an optical compensation function. Such an optical compensation film can be appropriately selected in accordance with each type of liquid crystal, and, for example, a resin in which a liquid crystal compound (for example, a discotic liquid crystal compound and / or a birefringence compound) is dispersed in triacetyl cellulose 1 type selected from the group consisting of 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, etc. What is obtained from the above can be mentioned.

  Since the optical compensation film is commercially available, it is also possible to select and use them appropriately. For example, "Wide View-EA" and "Wide View-T" (manufactured by Fujifilm Corporation) for TN systems, "Wide View-B" (manufactured by Fujifilm Corporation) for VA systems, VA-TAC (Konica Minolta Corporation) ), “Zeonor Film” (Nippon Zeon Co., Ltd.), “Arton” (JSR Co., Ltd.), “X-plate” (Nitto Denko Corp.), and “Z-TAC” for IPS system (Fuji Film Co., Ltd.) ), “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 through an adhesive layer. It is preferable to laminate via an adhesive from the point of adhesion improvement. The adhesive is not particularly limited, and any adhesive can be used. From the viewpoint of thinning the adhesive layer, it is preferable to use a water-based one (that is, one in which the adhesive component is dissolved in water or one dispersed in water). For example, in the case of 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 needed to improve adhesiveness. The composition can be used as an adhesive. 10 micrometers or less are preferable, as for the thickness of an adhesive bond layer, 5 micrometers or less are more preferable, and 3 micrometers or less are more preferable.

  When using a TAC film as a polarizer protective film, it can bond together using a polyvinyl alcohol-type adhesive agent. 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. As a photocurable resin, the mixture of a photocurable epoxy resin and a photocationic polymerization initiator etc. can be mentioned, for example.

  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, substrate film, scattering prevention film>
The image display apparatus can include a touch panel. The type and method of the touch panel are not particularly limited, and examples thereof include a resistive touch panel and a capacitive touch panel. The touch panel usually has one or more transparent conductive films regardless of the system. The transparent conductive film has a structure in which a transparent conductive layer is laminated on a base film. The image display device preferably comprises one or two base films, and at least one of the base films is preferably a high retardation alignment film. When an image display apparatus is provided with two base films, the base film which is a high retardation orientation film may be a light source side base film or a viewing side base film. When the image display device includes two base films, both of them may be high retardation oriented films, but one base film is a low retardation oriented film or the other conventionally used as a base film. Or a rigid plate such as a glass plate.

  As another film conventionally used as a base film, the various resin films which have transparency can be mentioned. 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 at least one resin selected from the group consisting of resins, polyphenylene sulfide resins and the like can be used. Among these, polyester resins, polycarbonate resins, and polyolefin resins are preferable, and polyester resins are preferable.

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

  The base film may be previously subjected to an etching treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical formation, oxidation, or undercoating treatment on the surface. 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., the surface of a base film may be dust-removed and cleaned by solvent washing | cleaning, ultrasonic cleaning, etc. as needed.

The transparent conductive layer may be laminated directly to the substrate film, but may be laminated via an easy adhesion layer and / or various other layers. As another layer, a hard-coat layer, an index matching (IM) layer, a low refractive index layer etc. can be mentioned, for example. Although the following six patterns can be mentioned as a lamination structure of a typical transparent conductive film, It is not necessarily limited to these.
(1) Base film / adhesive layer / transparent conductive layer (2) base film / adhesive layer / hard coat layer / transparent conductive layer (3) base film / adhesive layer / IM (index matching) layer / Transparent conductive layer (4) base film / easy adhesion layer / hard coat layer / IM (index matching) layer / transparent conductive layer (5) base film / easy adhesion layer / hard coat layer (also having high refractive index and IM) ) / Transparent conductive layer (6) base film / easy adhesion layer / hard coat layer (high refractive index) / low refractive index layer / transparent conductive thin film

The IM layer itself has a laminated structure of a high refractive index layer / a low refractive index layer (a transparent conductive thin film has a low refractive index layer on the side of the transparent conductive thin film). Can be obscured. As in the above (6), the high refractive index layer of the IM layer can be integrated with the hard coat layer, which is preferable from the viewpoint of thinning.

  The configurations (3) to (6) are particularly suitable for use in a capacitive touch panel. Moreover, the structure of said (2)-(6) is preferable at a viewpoint that oligomer can prevent precipitation on the surface of a base film, and it can provide a hard-coat layer also on the other 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 indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, tungsten A conductive metal oxide of at least one selected metal is used. The said metal oxide may contain the metal atom further shown by the said group as needed. Preferred transparent conductive layers are, for example, a tin-doped indium oxide (ITO) layer and an antimony-doped tin oxide (ATO) layer, preferably an ITO layer. In addition, the transparent conductive layer may be Ag nanowire, Ag ink, self-assembled conductive film of Ag ink, mesh electrode, CNT ink, conductive polymer.

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 still more preferably 20 to 30 nm. If the thickness of the transparent conductive layer is 15 nm or more, a good continuous film having a surface resistance of, for example, 1 × 10 ³ Ω / □ or less is easily obtained. Moreover, it can be set as a layer with high 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 evaporation method, a sputtering method, and an ion plating method can be exemplified. The transparent conductive layer may be amorphous or crystalline. As a method of 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 includes a pattern forming portion in which the transparent conductive layer is formed on the base film, and a pattern opening which does not have the transparent conductive layer on the base film. Have. The shape of the pattern forming portion may be, for example, not only a stripe but also a square.

The image display device preferably has one or more shatterproof films on the viewing side of the viewing side polarizer. Among them, the light source side anti-scattering film disposed on the light source side of the base film of the touch panel is preferably the above-described low retardation oriented film. Moreover, the shatterproof film can also use various films (for example, the transparent resin film described about the said base film) conventionally used as a shatterproof film. When two or more shatterproof films are provided, they may be formed of the same material or may be different.

  When using an orientation film as a scattering prevention film of the surface cover plate of an image display apparatus, arrangement of the orientation film may be on the light source side or on the viewing side of the surface cover plate. Moreover, it may be a laminated glass structure in which glass is laminated on both sides of the oriented film. When the alignment film is on the light source side of the surface cover plate, it is preferable to provide an antireflective layer on the side opposite to the surface cover plate of the alignment film. By providing the antireflective layer, a bright and clear image can be obtained.

  When using an oriented film as a scattering prevention film, it is preferable to provide an ultraviolet-ray absorption function to an oriented film. The application of the ultraviolet absorbing function can be performed by adding an ultraviolet absorber to the oriented film, or by applying an ultraviolet absorbing coating on the viewing side of the oriented film. When the oriented film is on the viewing side of the surface cover plate, it is preferable to provide an antireflective layer, an antiglare layer, an antistatic layer, an antifouling layer, etc. on the opposite side of the oriented film to the surface cover plate. In this case, an antireflective layer may be provided on the light source side of the surface cover plate on the outermost surface, or may be bonded to another member on the viewing side with an adhesive.

  A polarizer protective film, a substrate film, and a shatterproof film can contain various additives in the range which does not bar an effect of the present invention. For example, ultraviolet absorbers, inorganic particles, heat resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, light stabilizers, flame retardants, heat stabilizers, thermal stabilizers, antioxidants, antigelling agents And surfactants. In addition, in order to achieve high transparency, it is also preferable that the polyester film does not substantially contain particles. The phrase "does not substantially contain particles" means, for example, in the case of inorganic particles, containing 50 ppm or less by weight, preferably 10 ppm or less, particularly preferably the detection limit or less, when the inorganic element is quantified by fluorescent X-ray analysis. Means quantity.

  The oriented film may have various functional layers. As such a functional layer, for example, a hard coat layer, an antiglare layer, an antireflective layer, a low reflection layer, a low reflection antiglare layer, an antireflective antiglare layer, an antistatic layer, a silicone layer, an adhesive layer, antifouling 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 the antiglare layer, the antireflective layer, the low reflective layer, the low reflective antiglare layer, and the antireflective antiglare layer, the effect of improving color spots when viewed from an oblique direction can also be expected.

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

(Hard coat layer)
The hard coat layer may be any layer having hardness and transparency, and various types of curability such as ionizing radiation curable resin which is typically cured by ultraviolet light or electron beam, thermosetting resin which is cured by heat, etc. What was formed as a cured resin layer of resin is utilized. In order to appropriately add flexibility and other physical properties to these curable resins, thermoplastic resins may be added as appropriate. Among the curable resins, ionizing radiation curable resins are preferable in that representative and excellent hard coating films can be obtained.

  As the ionizing radiation curable resin, conventionally known resins may be appropriately adopted. In addition, as the ionizing radiation curable resin, radically polymerizable compounds having an ethylenic double bond, cationically polymerizable compounds such as epoxy compounds are typically used, and these compounds are monomers, oligomers, prepolymers, etc. As these, these can be used individually or in combination of 2 or more types suitably. Representative compounds are various (meth) acrylate compounds which are radically polymerizable compounds. As a compound used by comparatively low molecular weight among (meth) acrylate type compounds, for example, polyester (meth) acrylate, polyether (meth) acrylate, acrylic (meth) acrylate, epoxy (meth) acrylate, urethane (meth) ) Acrylate and the like.

  Monomers include, for example, monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like; 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 suitably used. (Meth) acrylate means acrylate or methacrylate.

  When the ionizing radiation curable resin is cured with an electron beam, a photopolymerization initiator is not necessary, but when curing with an ultraviolet ray, a known photopolymerization initiator is used. For example, in the case of a radical polymerization system, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether and 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, an aromatic sulfonium salt, an aromatic iodonium salt, a metatherone compound, a benzoin sulfonic acid ester, etc. 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 is usually 1 to 30 μm. The hard coat layer can be formed by appropriately employing 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 physical properties and the like as appropriate. As a thermoplastic resin or a thermosetting resin, an acrylic resin, a urethane resin, a polyester resin etc. are mentioned, for example.

  In order to impart light resistance to the hard coat layer and to prevent discoloration, strength deterioration, cracking and the like due to ultraviolet rays contained in sunlight and the like, it is also preferable to add an ultraviolet absorber to the ionizing radiation curable resin. When a UV absorber is added, it is preferable to cure the ionizing radiation curable resin with an electron beam in order to surely prevent the curing of the hard coat layer from being inhibited by the UV absorber. As the ultraviolet absorber, organic ultraviolet absorbers such as benzotriazole compounds and benzophenone compounds, fine particle zinc oxide having a particle diameter of 0.2 μm or less, inorganic ultraviolet absorbers such as titanium oxide and cerium oxide, etc. It may be selected from among known ones and used. The amount of the ultraviolet absorber added 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 the ultraviolet light absorber. The electron beam irradiation is performed at an accelerating 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, conventionally known ones may be appropriately adopted, and in general, the layer is 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. The shape of these fine particles is, for example, spherical or elliptical. 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, benzoguanamine-formaldehyde beads and the like. The fine particles can be generally added in an amount of about 2 to 30 parts by mass, preferably about 10 to 25 parts by mass, with respect to 100 parts by mass of the resin component.

  It is preferable that the resin for dispersing and holding the antiglare agent have a hardness as high as possible, as in the hard coat layer. Therefore, as said resin, curable resin etc., such as an ionizing radiation curable resin described in the said hard-coat layer, a thermosetting resin, etc. 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 employing various known coating methods. In order to prevent precipitation of the antiglare agent, it is preferable to appropriately add a known antisettling agent such as silica to the coating solution for forming the antiglare layer.

(Antireflection layer)
As the antireflective layer, conventionally known ones may be adopted appropriately. Generally, the antireflective layer comprises 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 laminated alternately and the surface side has a low refractive index It consists of a multilayer of layers. The thickness of each 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 in adjacent lamination and about 0.1 to 1 μm in the low refractive index layer alone. Is preferred.

  As the low refractive index layer, a layer containing a low refractive index substance such as silica or magnesium fluoride in a resin, a layer of a low refractive index resin such as a fluorine resin, a low refractive index substance 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, etc.), a layer containing a low refractive index substance such as silica, magnesium fluoride or the like, oxidation A film formed by a sol-gel method for forming a silicon oxide gel film from a sol solution of silicon, or a layer containing void-containing fine particles in a resin as a low refractive index substance, and the like can be mentioned.

  The void-containing fine particles are fine particles containing a gas inside, fine particles of a porous structure containing a gas, etc., and the entire refractive index of the solid portion of the fine particles makes it possible for the entire fine particles to It means particles having an apparent decrease in refractive index. Examples of such void-containing fine particles include silica fine particles disclosed in JP-A-2001-233611. Further, as the void-containing fine particles, in addition to inorganic substances such as silica, hollow polymer fine particles disclosed in JP-A-2002-85031 and the like can also be mentioned. The particle diameter of the void-containing fine particles is, for example, about 5 to 300 nm.

  As a high refractive index layer, a layer containing a high refractive index substance 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, a high refractive index substance Thin film forming method (for example, physical or chemical vapor deposition such as vapor deposition, sputtering, CVD, etc.) And thin films formed by

(Antistatic layer)
As the antistatic layer, conventionally known ones may be appropriately adopted, and in general, the resin is formed as a layer in which the antistatic layer is contained. Organic or inorganic compounds are used as the antistatic layer. For example, as an antistatic layer of an organic compound, a cationic antistatic agent, an anionic antistatic agent, an amphoteric antistatic agent, a nonionic antistatic agent, an organometallic antistatic agent, etc. may be mentioned. The inhibitor is used not only as a low molecular weight compound but also as a high molecular weight compound. In addition, as the antistatic agent, conductive polymers such as polythiophene and polyaniline can be used. In addition, conductive fine particles made of, for example, a metal oxide may be used as the antistatic agent. The particle size of the conductive fine particles is, for example, about 0.1 nm to 0.1 μm in average particle size 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) and the like can be mentioned.

  As the above-mentioned resin containing an antistatic layer, for example, as described in the above hard coat layer, a curable resin such as an ionizing radiation curable resin, a thermosetting resin, etc., etc. are used, In the case where the surface strength of the antistatic layer itself is unnecessary by forming it as a layer, a thermoplastic resin or the like is also used. The thickness of the antistatic layer may be appropriately set, and is usually about 0.01 to 5 μm. The antistatic layer can be formed by appropriately employing various known coating methods.

  When using an oriented film as a polarizer protective film, it is preferable to laminate | stack an antistatic layer on the surface layer. When laminating an antistatic layer, it is preferable to overlap and laminate an antistatic layer and an antiglare layer, or to add an antistatic agent to the antiglare layer to laminate a layer having both layers. Incidentally, when assembling the image display device, a polarizing plate protective film as a process member on the surface of the polarizing plate (unlike the polarizer protective film, can not be finally incorporated into the liquid crystal display device, and the liquid crystal display device is manufactured during the manufacturing process) In general, it is preferable to use an antistatic layer on the side of the polarizing plate protective film in contact with the polarizing plate or the opposite side thereof.

(Antifouling layer)
As the antifouling layer, conventionally known ones may be appropriately adopted, and in general, silicon-based compounds such as silicone oil and silicone resin in the resin; fluorine-based compounds such as fluorine-based surfactant and fluorine-based resin It can be formed by a known coating method using a paint containing an anti-stain agent such as wax. The thickness of the antifouling layer may be appropriately set, and can usually be about 1 to 10 μm.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited by the following examples, and is appropriately changed and implemented within the scope that can be adapted to the spirit of the present invention. It is also possible that they are all included in the technical scope of the present invention.

Test Example 1 Evaluation of Irid Spots In an image display having the following configuration, a polarizing film was disposed on the viewing side surface so as to be parallel to the viewing side surface to display a white image. The polarizing film is moved 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 is 0 °, 45 °, or 90 ° while maintaining the parallel state, The white image was viewed through the polarizing film at the points to confirm the presence or absence and degree of occurrence of rainbow marks and evaluated according to the following criteria.

<Evaluation criteria>
:: Rainbow spots are not observed when observed from the front.
Good: When observed from the front, rainbow marks are not observed at two or more points of the above angles of 0 °, 45 °, and 90 °.
X: When observed from the front, rainbow marks (uneven color) are observed at two or more points among the above-mentioned angles of 0 °, 45 °, and 90 °.

<Configuration of Image Display Device>
(1) Back light source: White LED or cold cathode tube (2) Light source side polarizing plate: A 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) Visual recognition side polarizing plate: A TAC film (Fuji Film Co., Ltd., thickness 80 μm) as a light source side protective film of a polarizer comprising PVA and iodine and a visual recognition side protective film Have. (5) Touch panel: A transparent conductive film (viewing side) created by providing a transparent conductive layer made of ITO on any of the orientation films 1 to 11 described later (visible side), and a transparent conductive made of ITO on a glass substrate A resistive film type touch panel having a structure in which an ITO glass (light source side) provided with a layer is disposed via a spacer.
(6) Scattering prevention film: Any of the alignment films A to C shown in Table 1 below was used as the scattering prevention film on the light source side of the touch panel.

Production Example-PET (A)
When the temperature of the esterification reactor reached 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. Then, the temperature was raised under pressure and the pressure esterification reaction was carried out under conditions of a gauge pressure of 0.34 MPa and 240 ° C. Then, the esterification reaction vessel was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Furthermore, the temperature was raised to 260 ° C. over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. Then, after 15 minutes, dispersion treatment was carried out with a high pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can, and a polycondensation reaction was performed at 280 ° C. under reduced pressure.

  After completion of the polycondensation reaction, filtration treatment is carried out with a Naslon (registered trademark) filter with a 95% cut diameter of 5 μm, extruded from the nozzle in a strand, and cooling water previously subjected to filtration treatment (pore diameter: 1 μm or less) The mixture was cooled, solidified, and cut into pellets. The intrinsic viscosity of the obtained polyethylene terephthalate resin (A) was 0.62 dl / g, and substantially no inert particles and internally precipitated particles were contained. (Hereafter, it is abbreviated as PET (A).)

Oriented film 1
Particle-free PET (A) resin pellets were dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours, then supplied to an extruder and dissolved at 285 ° C. This polymer is filtered with a filter material of a stainless steel sintered body (nominal filtration accuracy 10 μm particles 95% cut), extruded into a sheet form from a die and extruded, and then cast onto a casting drum with a surface temperature of 30 ° C. using electrostatic application casting. The film was wound and solidified by cooling to form an unstretched film.

The unstretched film was guided to a tenter stretching machine, and while holding the end of the film with a clip, it was guided to a hot air zone at a temperature of 125 ° C. 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 relaxation treatment of 3% in the width direction is performed to obtain an oriented film 1 having a uniaxial thickness of about 50 μm. The

Oriented film 2
By changing the thickness of the unstretched film, an orientation film 2 of uniaxial orientation was obtained in the same manner as the orientation film 1 except that the thickness of the film was about 100 μm.

Oriented film 3
The unstretched film is heated to 105 ° C. using a heated roll group and an infrared heater, and thereafter stretched 1.5 times in the traveling direction with a roll group having a peripheral speed difference, and then in the same manner as the alignment film 1 A biaxially oriented alignment film 3 having a film thickness of about 50 μm was obtained in the same manner as the alignment film 1 except that the film was stretched 4.0 times in the width direction.

Oriented film 4
A biaxially oriented alignment film 4 having a film thickness of about 50 μm was obtained in the same manner as the alignment film 3 except that the film was stretched 2.0 times in the running direction and 4.0 times in the width direction.

Oriented film 5
A biaxially oriented orientation film 5 having a film thickness of about 75 μm was obtained in the same manner as the orientation 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 6
A polymer solution was prepared by dissolving polycarbonate (manufactured by Aldrich) in 4-fold by weight methylene chloride. The polymer solution was developed with a knife coater into a smooth glass plate 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 from the obtained polycarbonate sheet in a dumbbell shape. The sheet sample cut out was heated at a temperature of about 160 ° C. using Tensilon (manufactured by Orientec) and stretched uniaxially. At that time, by adjusting the draw ratio and the draw speed, an orientation film 6 of uniaxial orientation having a retardation of 9087 nm was obtained.

Oriented film 7
A biaxially oriented alignment film 7 having a film thickness of about 38 μm was obtained in the same manner as the alignment 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 8
An orientation film 8 with a uniaxial orientation of about 10 μm in thickness was obtained in the same manner as the orientation film 1 except that the thickness of the unstretched film was changed.

Oriented film 9
A biaxially oriented alignment film 9 having a film thickness of about 188 μm was obtained in the same manner as the alignment film C except that the film was stretched 3.6 times in the running direction and 4.0 times in the width direction.

Oriented film 10
An orientation film 10 having a uniaxial thickness of about 100 μm was obtained in the same manner as the orientation film 3 except that the film was stretched by 4.0 times in the running direction and 1.0 times in the width direction.

Oriented film 11
An orientation film 11 of uniaxial orientation was obtained in the same manner as the orientation film 10 except that the stretching ratio in the running direction was stretched to 3.6 times.

  Physical properties of the obtained film are shown in Table 2.

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

  The evaluation results are shown in Table 3 below.

  As shown in Table 3, by using a low retardation alignment film as a light source side scattering prevention film and using a high retardation alignment film as a base film, an image is viewed through a polarizing filter while using a low retardation alignment film It was confirmed that the drop in visibility due to the disturbance of the color tone such as rainbow marks can be effectively suppressed. Moreover, this effect is remarkable when the orientation main axis of the low retardation orientation film and the polarization axis of the viewing side polarizer are substantially parallel or perpendicular, and the angle formed by the two axes is 10 degrees or 30 degrees. In the case where an iridescent spot was observed depending on the angle at which the image is viewed, if the image is viewed from an angle at which at least the polarization axis of the polarizing filter and the polarization axis of the viewing side polarizer are substantially parallel or perpendicular, Good visibility was obtained.

Test Example 2: Visibility Dependent on the Angle Between the Polarization Axis of a Polarizer and a Polarizing Filter A low retardation alignment film, a high retardation alignment film, and a polarizing filter are in this order on the viewing side surface of a liquid crystal display device using a white LED as a light source. And the angle formed by the polarization axis of the viewing side polarizer and the polarization axis of the polarization filter (polarization axis-polarization axis angle) is 0 degrees, 45 degrees, or 9
It was fixed at 0 degrees. Then, at each polarization axis-polarization axis angle, an angle formed by the alignment main axis of each alignment film and the polarization axis of the viewing side polarizer while rotating the low retardation alignment film and / or the high retardation alignment film clockwise The relationship between orientation main axis-polarization axis angle) and the appearance of iridescent spots was evaluated. The evaluations are as follows: (I) no rainbow spots, (II) a thin rainbow spot, (III) a clear rainbow spot, and (IV) a case where the screen appears dark due to a decrease in luminance. It evaluated in four steps. The charts showing the results when the polarization axis-polarization axis angle is 0 degree, 90 degrees and 45 degrees are shown in FIG. 2, FIG. 3 and FIG. 4 respectively.

  As shown in FIG. 2, when the polarization axis-polarization axis angle is 0 degree, the orientation of the high retardation alignment film is centered on the case where the alignment main axis-polarization axis angle of the low retardation orientation film is 45 degrees. A tendency was observed that iridescent spots were observed as the principal axis-polarization axis angle approached 0 degrees or 90 degrees. In particular, if the orientation main axis-polarization axis angle for the low retardation orientation film is about 40 to 50 degrees, then the orientation main axis-polarization axis angle for the high retardation orientation film is about 0 to 25 degrees or about 65 to 90 degrees There was a clear rainbow spot in some cases. In addition, when the alignment main axis-polarization axis angle for the low retardation alignment film is about 30 to 40 degrees or 50 to 60 degrees, the alignment main axis-polarization axis angle for the high retardation alignment film is about 0 to 35 degrees or about Thin iridescent spots were seen at 60-90 degrees. From this result, when the angle formed by the polarization axis of the polarization filter such as polarization sunglasses and the polarization axis of the image display device is substantially parallel, low retardation is produced in the area other than the angle area where the above-mentioned rainbow marks are observed. It has been shown that it is preferable to arrange oriented films and high retardation oriented films.

  As shown in FIG. 3, when the polarization axis-polarization axis angle is 90 degrees, the alignment main axis-polarization axis angle for the low retardation alignment film is 0 degree or near 90 degrees, and the high retardation alignment film It was confirmed that the screen becomes dark when the orientation main axis-polarization axis angle is near 0 or 90 degrees. In addition, except for the area where the screen becomes dark, iridescence was observed when the alignment main axis-polarization axis angle for the high retardation alignment film was 0 degrees or near 90 degrees. In particular, an alignment main axis for a high retardation alignment film-a clear rainbow mark is observed when the polarization axis angle is about 0 to 10 degrees or about 80 to 90 degrees, and an alignment main axis-polarization axis for a high retardation alignment film Thin iridescent spots were observed at angles of about 10 to 20 degrees or about 70 to 80 degrees. From this result, when the angle formed by the polarization axis of the polarization filter such as polarization sunglasses and the polarization axis of the image display device is approximately 90 degrees, the alignment main axis-polarization axis angle for the high retardation alignment film is 10 degrees to It has been shown that it is preferable to arrange the high retardation alignment film so as to be 80 degrees, preferably 20 to 70 degrees.

  As shown in FIG. 4, when the polarization axis-polarization axis angle is 45 degrees, the screen does not become dark regardless of the alignment main axis-polarization axis angle. On the other hand, iridescence was observed in the two regions divided by three points represented by the following alignment main axis-polarization axis angle: (A) Alignment main axis-polarization axis angle for low retardation alignment film, and (B The alignment main axis-polarization axis angle for the high retardation alignment film is (A) about 30 degrees · (B) about 20 degrees, (A) about 60 degrees · (B) about 15 degrees, and (A) 70 degrees · (B) A region connecting three points of 45 degrees with a line, (A) 20 degrees · (B) 45 degrees, (A) 30 degrees · (B) 80 degrees, and (A) 50 degrees · (B ) An area where three points of 75 degrees are connected by a line. Also, as the center of the two regions was approached, more distinct rainbow marks were observed. From this result, when the angle formed by the polarization axis of the polarization filter such as polarization sunglasses and the polarization axis of the image display device is about 45 degrees, the low retardation alignment film and the high retardation are set to be other than the above two regions. It has been shown that it is preferable to bond the oriented film.

In Test Example 2, the degree of iridescence was significantly reduced even in the region where iridescence was clearly observed, as compared to the case where only the low retardation alignment film was used.

DESCRIPTION OF SYMBOLS 1 liquid crystal display device 2 light source 3 light source side polarizing plate 4 liquid crystal cell 5 viewing side polarizing plate 6 touch panel 7 light source side polarizer 8 viewing side polarizer 9a polarizer protective film 9b polarizer protective film 10a polarizer protective film 10b viewing side polarized light Child protective film 11 light source side transparent conductive film 11a light source side substrate film 11b transparent conductive layer 12 viewing side transparent conductive film 12a viewing side substrate film 12b transparent conductive layer 13 spacer 14 light source side scattering prevention film 15 viewing side scattering prevention the film

Claims (5)

(1) White light source having continuous emission spectrum,
(2) Image display cell,
(3) A polarizing plate disposed closer to the viewer than the image display cell
(4) It has a scattering prevention film arrange | positioned on visual recognition side rather than the said polarizing plate, and (5) The touch panel arrange | positioned on the visual recognition side rather than the said scattering prevention film,
The touch panel is a structure having a base film on which a transparent conductive layer is laminated and a glass base on which a transparent conductive layer is laminated,
The base film is disposed closer to the viewing side than the glass base,
The anti-scattering film is laminated to the glass substrate via an adhesive layer,
The anti-scattering film is an oriented film having a retardation of less than 3000 nm,
The base film is an oriented film having a retardation of 3000 nm or more and 150000 nm or less,
The base film is disposed such that the alignment main axis thereof is 45 ° ± 20 ° or less with respect to the polarization axis of the polarizer of the polarizing plate.
The anti-scattering film is disposed such that the alignment main axis and the polarization axis of the polarizer of the polarizing plate are 0 ° ± 5 ° or less or 90 ° ± 5 ° or less.
Image display device. The image display device according to claim 1, wherein the base film is disposed such that an alignment main axis thereof is 45 degrees with respect to a polarization axis of a polarizer of the polarizing plate. The said scattering prevention film is arrange | positioned so that the orientation main axis | shaft and the polarization axis of the polarizer of the said polarizing plate may be 0 degree +/- 4 degree or less, or 90 degree +/- 4 degree or less. Image display device. The image display according to any one of claims 1 to 3, wherein a ratio (Re / Rth) of retardation (Re) to retardation in a thickness direction (Rth) of the base film is 0.2 or more and 1.2 or less. apparatus. The image display apparatus according to any one of claims 1 to 4, wherein the white light source having the continuous light emission spectrum is a white light emitting diode.