JP6382491B2 - Touch panel and image display device including the same - Google Patents

Description

  The present invention relates to a touch panel in which generation of Newton rings is suppressed, and an image display device using the touch panel.

  2. Description of the Related Art In recent years, touch-input type image display devices have been rapidly spread mainly in mobile phones (particularly smartphones) and tablet-type portable information terminals. In the touch input type image display device, a touch panel for detecting touch position information is arranged on the viewing side of the image display element. As the image display element in this case, a liquid crystal cell, an organic electroluminescence (EL) display element, or the like is often used. On the other hand, there are various types of touch panels, but currently the mainstream are the resistive film type and the capacitive type.

  The resistive film type touch panel is arranged so that two substrates having transparent electrodes are kept in a gap and each transparent electrode faces each other, and the two transparent electrodes are brought into contact with each other by pressing with a finger or the like. Thus, the touch position is detected. Examples thereof include those described in JP-A-2005-11312 (Patent Document 1) and JP-A-2012-59245 (Patent Document 2). As described above, a resistive film type touch panel always has a gap between two substrates.

  On the other hand, a capacitive touch panel detects a touch position by detecting a change in surface charge of a portion touched by a finger. Examples thereof include those described in JP 2012-48279 A (Patent Document 3) and JP 2012-181828 A (Patent Document 4). In a capacitive touch panel, although a gap is not essential, a gap may be provided between the display element side substrate (see FIG. 7 of Patent Document 3).

  In particular, when there is a gap (gap) between the substrates, interference fringes called Newton rings are generated when the screen is touched with a finger or the like for operation. If the Newton ring is a resistive film type touch panel, the screen is pressed and the gap between the upper and lower transparent electrodes is eliminated to bring them into contact with each other. In the case of a capacitive touch panel, this occurs due to interference of multiple reflected light in the gap when the distance of the gap changes or when the touch input element comes into contact with the display element side substrate. When Newton rings occur, the visibility is reduced, and countermeasures are required.

  In Patent Document 2, an image display element such as a liquid crystal panel and a front plate (indicated as “window” in the same document) disposed on the forefront of the touch panel are directly bonded to each other with an adhesive layer. The above-mentioned Newton ring is generated by accommodating a touch panel composed of two substrates in the space formed thereby, and preventing a gap between the image display element and the image display element side substrate. Is suppressed. Patent Document 2 also discloses a capacitive touch panel as a second embodiment.

  In addition, as a measure for preventing the occurrence of Newton's ring, a method is known in which the surfaces of electrodes and image display elements are roughened to scatter reflected light from the surface. For example, in JP 2008-155387 A (Patent Document 5), a transparent conductive film is formed on one surface of a resin molded body having a thickness of 0.1 to 1 mm obtained by curing a photopolymerizable composition. A laminated body in which the transparent conductive film forming surface of the resin molded body is an uneven surface having an arithmetic average roughness Ra of 50 to 150 nm is disclosed, and Newton's ring is suppressed by forming such surface unevenness It is supposed to be possible. It is also disclosed that this laminate is used as a substrate with a transparent electrode for a touch panel. However, Newton's ring may not always be effectively suppressed by controlling the arithmetic average roughness Ra, particularly when the average roughness is 100 nm or less.

  In addition, when the surface is roughened, scattering generally increases, so that there is a problem that the screen becomes whitish or the contrast is lowered. In order to prevent whitishness, it is necessary to reduce haze or surface roughness. However, in that case, a sufficient Newton ring prevention effect may not be obtained.

  On the other hand, it is also conceivable to provide an antireflection layer on the surface of the electrode or image display element to reduce multiple reflections and prevent Newton rings from occurring. However, although the antireflection layer is effective in preventing whitishness and reduction in contrast, there is a problem that the cost is increased.

Japanese Patent Laid-Open No. 2005-11312 JP 2012-59245 A JP 2012-48279 A JP 2012-181828 A JP 2008-155387 A

  An object of the present invention is to suppress the occurrence of Newton rings in a touch panel having a gap between two substrates by disposing an optical film having a specific surface shape on the gap side surface.

  As a result of repeated research under such a problem, an optical film having fine irregularities on the surface and having a small absolute value of skewness Psk, which is an index representing the degree of distortion or distortion of the probability density function of the cross-sectional curve, It is found that it is effective to suppress the Newton ring by arranging the uneven surface on the gap side, and further, reducing the arithmetic average inclination angle Δa of the optical film surface further suppresses the Newton ring. I found it effective. The present invention has been completed based on these findings and further various studies.

  That is, according to the present invention, the display element side substrate and the touch input element are arranged with a gap therebetween, and the transparent support is provided on at least one of the gap side surface of the display element side substrate and the gap side surface of the touch input element. And an optical film formed thereon having a fine surface irregularity shape having an absolute value of the skewness Psk of the cross-sectional curve of 0.3 or less, the coating layer side in the above gap A touch panel is provided that is oriented toward.

  In this touch panel, in one preferred embodiment, the optical film is disposed only on the gap side surface of the display element side substrate. In another preferred embodiment, the optical film is disposed on each of the gap side surface of the display element side substrate and the gap side surface of the touch input element. In any of these forms, the display element side substrate may be a polarizing plate, and the above optical film may be disposed on the surface thereof.

  In these touch panels, the coating layer of the optical film preferably has an arithmetic average inclination angle Δa of 1 ° or less. The coating layer of the optical film preferably has an arithmetic average roughness Ra of 100 nm or less. Further, the above optical film preferably has a total haze of 3% or less, and preferably has an external haze of 3% or less.

  Moreover, according to this invention, a touch input type image display apparatus provided with the image display element represented by the liquid crystal cell and the organic EL display element, and one of the said touchscreens arrange | positioned at the visual recognition side is also provided.

  The touch panel of the present invention has a gap between the display element side substrate and the touch input element, and has a specific surface on at least one of the gap side surface of the display element side substrate and the gap side surface of the touch input element. The optical film on which fine unevenness having a shape is formed is arranged so that the uneven surface is on the gap side. And this optical film has a Newton ring that is likely to occur at the time of touch input even if the external haze is reduced or the surface roughness is reduced in order to suppress whitishness and decrease in contrast. It can be effectively suppressed. Similarly, the touch-input type image display device in which the touch panel is incorporated in the image display element is effectively suppressed from generating Newton rings.

It is a cross-sectional schematic diagram which shows embodiment at the time of applying this invention to a resistive film type touch panel. It is a cross-sectional schematic diagram which shows embodiment at the time of applying this invention to a capacitive touch panel. It is a schematic diagram of a cross-sectional curve showing how to obtain the arithmetic average inclination angle Δa of the cross-sectional curve. It is a cross-sectional schematic diagram which shows a preferable form about the method of manufacturing an optical film continuously. It is a cross-sectional schematic diagram which shows an example of a touch input type image display apparatus.

  In the present invention, the display element side substrate and the touch input element are arranged with a gap therebetween, and at least one of the gap side surface of the display element side substrate and the gap side surface of the touch input element has a specific An optical film on which fine unevenness having a surface shape is formed is arranged so that the uneven surface is on the gap side, thereby forming a touch panel. FIG. 1 is a schematic cross-sectional view showing an embodiment of a resistive film type touch panel to which the present invention is applied. FIG. 2 is a schematic cross-sectional view showing an embodiment of a capacitive touch panel to which the present invention is applied.

  First, with reference to FIG. 1 showing an embodiment of a resistive film type touch panel, a configuration common to each of the forms (a), (b) and (c) will be described. The display element side substrate 10 and the touch input element 20 are disposed with a gap 50 therebetween, and transparent conductive layers 15 and 25 serving as electrodes are formed on the outermost surface on the gap 50 side of the display element side substrate 10 and the outermost surface on the gap 50 side of the touch input element 20, respectively. ing. The transparent conductive layers 15 and 25 play a role for detecting the position of the touch input element 20 when the touch input element 20 side is pressed with a finger or the like, and the two come into contact with each other.

  In the first embodiment shown in FIG. 1 (a), a transparent support 31 and a coating layer 32 having fine irregularities formed thereon are formed on the gap 50 side of the display element side substrate 10. The optical film 30 is disposed with the uneven surface on the coating layer 32 side set to the gap 50 side. In this case, the transparent conductive layer 15 on the display element side is formed on the uneven surface on the coating layer 32 side of the optical film 30.

  In the second mode shown in FIG. 1 (b), the touch input element 20 is formed of a transparent support 41 and a coating layer 42 having fine irregularities formed thereon on the gap 50 side. The optical film 40 is disposed such that the uneven surface on the coating layer 42 side is the gap 50 side. In this case, the transparent conductive layer 25 on the touch input element side is formed on the uneven surface on the coating layer 42 side of the optical film 40.

  In the third embodiment shown in FIG. 1C, the transparent element 31 and the coating layer 32 having fine irregularities formed thereon are formed on the gap 50 side of the display element side substrate 10. The optical film 30 is disposed with the uneven surface on the coating layer 32 side set to the gap 50 side, and the transparent support 41 and the fine support formed thereon are also formed on the gap 50 side of the touch input element 20. An optical film 40 composed of an uneven coating layer 42 is arranged with the uneven surface on the coating layer 42 side facing the gap 50. In this case, the transparent conductive layer 15 on the display element side is formed on the uneven surface on the coating layer 32 side of the optical film 30, and the transparent conductive layer 25 on the touch input element side is formed on the uneven surface on the coating layer 42 side of the optical film 40. Is done.

  Next, with reference to FIG. 2 showing an embodiment of a capacitive touch panel, a configuration common to each of the forms (a), (b), and (c) will be described. The input element 20 is disposed with a gap 50 therebetween. In the capacitance type shown in FIG. 2, only the touch input element 20 shown in FIG. 2 may be referred to as a touch panel. In the present invention, the touch input element 20 and the touch input element 20 are arranged with a gap therebetween. A combination of the display element side substrates 10 is referred to as a touch panel.

  In the first embodiment shown in FIG. 2A, the transparent support 31 and the coating layer 32 having fine irregularities formed thereon are formed on the gap 50 side of the display element side substrate 10. The optical film 30 is disposed with the uneven surface on the coating layer 32 side set to the gap 50 side.

  In the second mode shown in FIG. 2B, the touch input element 20 includes a transparent support 41 and a coating layer 42 having fine irregularities formed thereon on the gap 50 side. The optical film 40 is disposed such that the uneven surface on the coating layer 42 side is the gap 50 side.

  In the third embodiment shown in FIG. 2C, the transparent support 31 and the coating layer 32 having fine irregularities formed thereon are formed on the gap 50 side of the display element side substrate 10. The optical film 30 is disposed with the uneven surface on the coating layer 32 side set to the gap 50 side, and the transparent support 41 and the fine support formed thereon are also formed on the gap 50 side of the touch input element 20. An optical film 40 composed of an uneven coating layer 42 is arranged with the uneven surface on the coating layer 42 side facing the gap 50.

  In any of the above forms, an image display element (not shown) is arranged on the opposite side (lower side in each figure) of the display element side substrate 10 to the touch input type image display device. Hereinafter, each member constituting the touch panel of the present invention will be described in order, a suitable manufacturing method of the optical film defined in the present invention will be described, and then a supplementary explanation on the touch panel and a description on the touch input type image display device will be given. Go ahead.

[Display element side substrate]
The display element side substrate 10 can be composed of a glass plate or various transparent resin films. In particular, when a liquid crystal cell or an organic EL display element is employed as the image display element, the polarizing plate disposed on the viewing side can be used as the display element side substrate 10 in FIGS. The polarizing plate is composed of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin and linear polarization ability is imparted, and preferably a protective film made of a transparent resin is bonded on both sides. be able to. A retardation plate may be further arranged on the display element side of the polarizing plate. In addition, one protective film of the polarizing plate, in particular, the protective film on the display element side can be formed of a retardation plate provided with a retardation. When the image display element is a liquid crystal cell, a retardation plate having a predetermined retardation value is used according to the type of the liquid crystal cell. On the other hand, when the image display element is an organic EL display element, the retardation plate is composed of a quarter-wave retardation plate and combined with a polarizing film to form a circularly polarizing plate also serves as an antireflection function. Are preferably used.

Retardation plate, an optical film in which the phase difference is imparted by such stretching, the optical characteristics, the direction perpendicular to the refractive index in the in-plane slow axis direction n _x, the slow axis in the plane (phase advancing The in-plane retardation value Ro defined by the following formula (I) and the following formula (n), where n _{y is} the refractive index in the axial direction), n _{z is} the refractive index in the thickness direction, and d is the thickness of the film: It can be expressed by the thickness direction retardation value Rth defined in II).

_{Ro = (n x -n y)} × d (I)
Rth = _{[(n x + n y) /} 2-n z ] × d (II)

  What is necessary is just to employ | adopt the phase difference plate which shows a suitable phase difference value in combination with a liquid crystal cell or an organic EL display element. A film formed by the melt extrusion method has an optical axis formed in the extrusion direction and a slight retardation is developed in the plane. A film formed by the solution casting method has an optical axis in the thickness direction. Is formed, and a certain amount of phase difference appears in that direction. There is also a commercially available film in which such inevitable retardation is further reduced and the in-plane and thickness direction retardation values are almost zero. Thus, the in-plane and thickness direction retardation values are almost zero. The film formed may be referred to as a retardation plate.

[Touch input element]
The touch input element 20 can also be comprised with a glass plate and various transparent resin films. In the resistive film type touch panel shown in FIG. 1, the touch input element 20 is bent by touching, and a transparent conductive layer 25 provided on the back surface thereof is provided on the surface of the display element side substrate 20. The touch input element 20 is often made of a flexible transparent resin film such as a polyethylene terephthalate film because the touch position is detected by touching the transparent conductive layer 15. On the other hand, in the capacitive touch panel shown in FIG. 2, flexibility is not particularly required. Therefore, both the glass plate and the transparent resin film can be used as the touch input element 20.

[Optical film with irregularities]
In the present invention, the display element side substrate 10 and the touch input element 20 are arranged with a gap 50 between them, and the surface of the display element side substrate 10 on the gap 50 side and the gap 50 of the touch input element 20 are arranged. The optical films 30 and 40 having fine irregularities formed on at least one of the side surfaces and having a specific surface shape are arranged so that the irregular surfaces are on the gap side, and generation of Newton rings is suppressed. Touch panel. The optical film 30 provided on the display element side substrate 10 is composed of a transparent support 31 and a coating layer 32 having fine irregularities formed thereon. The optical film 40 provided on the touch input element 20 is also composed of a transparent support 41 and a coating layer 42 having fine irregularities formed thereon.

<Transparent support>
The transparent supports 31 and 41 only need to be translucent, and for example, glass or a transparent resin film can be used. The resin film should just have moderate transparency and mechanical strength. Specific examples of resins constituting the transparent supports 31 and 41 include cellulose acetate resins represented by triacetyl cellulose, acrylic resins, polycarbonate resins, and polyester resins represented by polyethylene terephthalate. Can be used. The thickness of the transparent supports 31 and 41 can be, for example, in the range of about 10 to 500 μm, and preferably in the range of 20 to 300 μm.

<Coating layer>
The coating layers 32 and 42 having fine irregularities are formed on the surfaces of the transparent supports 31 and 41 to obtain optical films 30 and 40 having a Newton ring prevention function. The coating layers 32 and 42 can be formed by application of a translucent resin. The surfaces of the coating layers 32 and 42 are set so that the absolute value of the skewness Psk of the sectional curve is 0.3 or less. The formation of a fine concavo-convex surface can be achieved by adding fine particles in the translucent resin, or by attaching a mold having an concavo-convex surface (embossed type) to the coating layer of the translucent resin, and making the concavo-convex surface the coating layer. It can be performed by a transfer method or the like.

  The translucent resin used for forming the coating layers 32 and 42 only needs to be translucent, and for example, curing of an active energy ray curable resin such as an ultraviolet curable resin or an electron beam curable resin. Product, a cured product of a thermosetting resin, a thermoplastic resin, a cured product of a metal alkoxide, and the like. Among these, active energy ray-curable resins are preferable because they can impart high hardness and high scratch resistance. When an active energy ray-curable resin, a thermosetting resin, or a metal alkoxide is used, the resin is cured by irradiation with active energy rays or heating to form the coating layers 32 and 42.

  Examples of the active energy ray-curable resin include polyfunctional (meth) acrylates such as acrylic acid or methacrylic acid ester of polyhydric alcohol; terminal isocyanato group urethane prepolymer obtained by reaction of diisocyanate and polyhydric alcohol, acrylic acid or methacrylic acid. Examples thereof include polyfunctional urethane (meth) acrylates such as those synthesized by reacting a hydroxyalkyl ester of an acid. Here, “(meth) acrylate” means acrylate or methacrylate. In addition to these, polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can also be active energy ray curable resins.

  Examples of the thermosetting resin include a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, and a silicone resin in addition to a thermosetting urethane resin composed of an acrylic polyol and an isocyanate prepolymer.

  Thermoplastic resins include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose; vinyl acetate homopolymers or copolymers, vinyl chloride homopolymers or copolymers, and chlorides. Vinyl resins such as vinylidene homopolymers or copolymers; Acetal resins such as polyvinyl formal and polyvinyl butyral; Acrylic resins or acrylate copolymers, and methacrylic resins or methacrylate copolymers Examples thereof include acrylic resins such as coalescence; polystyrene resins; polyamide resins; polyester resins; polycarbonate resins.

  As the metal alkoxide, an alkoxysilane-based material can be used, and a silicon oxide-based matrix is formed by hydrolysis or dehydration condensation. Specifically, it is tetramethoxysilane, tetraethoxysilane, or the like, and forms an inorganic or organic-inorganic composite matrix by hydrolysis or dehydration condensation to become a translucent resin.

  Among these, active energy ray curable resins and thermosetting resins (both before curing) are prepared in a liquid state, and metal alkoxides are often liquid. As described above, the resin prepared in a liquid state can be used as it is as a coating solution for forming the coating layers 32 and 42, but if necessary, the coating solution may be diluted with a solvent or the like. . On the other hand, a resin prepared as a solid containing a thermoplastic resin is used as a coating solution in a state dissolved in an appropriate solvent. The coating liquid containing these active energy ray-curable resins, thermosetting resins, metal alkoxides, or thermoplastic resins may contain appropriate additives such as leveling agents and dispersants.

  In a coating liquid containing a translucent resin, for example, a coating liquid containing an active energy ray curable resin, translucent fine particles may be added in order to impart internal haze for the purpose of reducing glare and the like. . In addition, translucent fine particles may be used to form surface irregularities. As the light-transmitting fine particles to be added, those conventionally known in the field such as an antiglare film can be used for this purpose. For example, organic fine particles made of acrylic resin, melamine resin, polyethylene, polystyrene, organic silicone resin, acrylate-styrene copolymer, calcium carbonate, silica, aluminum oxide, barium carbonate, barium sulfate, titanium oxide, glass Inorganic fine particles composed of the above are used as translucent fine particles. Organic polymer balloons and glass hollow beads can also be used. These translucent fine particles may be used individually by 1 type, and may mix and use 2 or more types. The shape of the translucent fine particles may be any of a spherical shape, a flat shape, a plate shape, a needle shape, an indefinite shape, and the like.

  When translucent fine particles are contained in a translucent resin, for example, an active energy ray-curable resin, the particle diameter and refractive index of the translucent fine particles to be used are not particularly limited. Also when it aims at surface unevenness formation, it is preferable that the particle diameter exists in the range of 0.5-20 micrometers. If the particle diameter is within this range, the internal haze can be effectively expressed. For the same reason, when the purpose is to develop internal haze, the difference between the refractive index after curing of the active energy ray-curable resin and the refractive index of the translucent fine particles is in the range of 0.04 to 0.15. It is preferable that it exists in. The content of the translucent fine particles is usually 3 to 60 parts by weight, preferably 5 to 50 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin. When the content of the light-transmitting fine particles is less than 3 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin, it is difficult to obtain a sufficient internal haze for reducing glare. On the other hand, when the content exceeds 60 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin, the transparency of the obtained optical films 30 and 40 may be impaired, and this optical film is incorporated. When the touch panel is applied to the image display element, light scattering is too strong. For example, light that leaks obliquely with respect to the front direction of the image display device in the black display is directed to the front direction by the coating layers 32 and 42. The contrast may be lowered due to strong scattering.

<Surface shape of optical film>
In the present invention, as the optical films 30 and 40 disposed on the gap 50 side of the display element side substrate 10 and / or the touch input element 20, the coating layers 32 and 42 have an absolute value of the skewness Psk of the cross-sectional curve of 0. .3 or less surface shape shall be adopted. Here, the skewness Psk of the cross-sectional curve is JIS B0601: 2013 “Product Geometric Specification (GPS) —Surface Properties: Contour Curve Method—Terms, Definitions, and Surface Properties Parameters” (ISO 4287: 1997, Amd.1: 2009 4.2.3), which is defined by the following formula (III).

  Where Z (x) is the height of the cross section curve at an arbitrary position x, Lp is the reference length of the cross section curve (equal to the evaluation length), and Pq is the root mean square height of the cross section curve. Therefore, it is defined as the following formula (IV) in 4.2.2 of JIS B0601: 2013.

  As can be seen from these equations, the skewness Psk of the cross-sectional curve is the root mean square of Z (x) at the reference length Lp made dimensionless by the cube of the root mean square height Pq of the cross-sectional curve. In the above JIS B0601: 2013, the standard length L is displayed in lowercase italic el (l), but in this specification, in order to make it easier to distinguish from the number 1 (1), Displayed in L (L).

  The skewness Psk of the cross-sectional curve is a parameter that defines the degree of distortion (distortion) of the distribution state of the peaks and valleys constituting the cross-sectional curve, that is, a parameter indicating the degree of asymmetry of the probability density function of the cross-sectional curve. In statistical terms, it is called “degree of distortion”. If the distribution is normal, the skewness Psk of the cross-sectional curve is zero (0).

  If the absolute value of the skewness Psk of the cross-sectional curve defined in this way is 0.3 or less, the Newton ring becomes difficult to be visually recognized when the touch input element 20 of the touch panel is pressed with a finger or the like. If the value exceeds 0.3, the Newton ring will be visible. The absolute value of the skewness Psk of the cross-sectional curve is preferably closer to zero (0), and more preferably, for example, 0.2 or less.

Moreover, it is preferable that the coating layers 32 and 42 of the optical films 30 and 40 have a surface shape in which the arithmetic average inclination angle Δa in the cross-sectional curve is 1 ° or less. Here, the arithmetic average inclination angle Δa is a value obtained by dividing the cross-section curve in the horizontal direction at a constant interval ΔX, and obtaining the absolute value of the slope (angle) of the line segment connecting the start point and end point of the cross-section curve in each section. (Refer to the Internet <URL: http://www.fujimfg.co.jp/benri/roughness_del-a.htm>, retrieved on June 17, 2013). Referring to FIG. 3 which is a schematic diagram of a cross-sectional curve showing how to obtain the arithmetic average inclination angle Δa of the cross-sectional curve, there are n separations for measurement at the reference length L [measurement location is (n−1 )], And the vertical height of the cross-sectional curve in the i-th measurement section ΔX is ΔYi, the inclination angle in each measurement section ΔX is tan ⁻¹ (ΔYi / ΔX), and the arithmetic average inclination angle Δa is It calculates | requires by the following Formula (V).

  When the absolute value of the skewness Psk of the cross-sectional curve described above is 0.3 or less, and the arithmetic average inclination angle Δa is 1 ° or less, the Newton ring is further less visually recognized.

  Furthermore, the coating layers 32 and 42 preferably have a surface shape with an arithmetic average roughness Ra of 100 nm or less. The arithmetic average roughness Ra here is also a value defined in 4.2.1 of JIS B0601: 2013, and means an average value of absolute values of the height Z (x) at the reference length. The absolute value of the skewness Psk of the cross-sectional curve described above is 0.3 or less, or the arithmetic average inclination angle Δa is 1 ° or less and the arithmetic average roughness Ra is 100 nm or less. , Newton's ring will be less visible.

  The skewness Psk of the cross-sectional curve, which is a surface shape parameter, or its absolute value, the arithmetic average inclination angle Δa, and the arithmetic average roughness Ra can be measured using a commercially available three-dimensional shape measuring device, a roughness meter, or the like. In Examples described later, the measurement was performed using a three-dimensional microscope “PLμ 2300” manufactured by SENSOFAR. This apparatus is designed to automatically calculate specified parameters for the measurement sample.

  As described above, in order to suppress the occurrence of Newton rings, the coating layers 32 and 42 make the absolute value of the skewness Psk of the cross-sectional curve approach zero (0), and the arithmetic average inclination angle Δa and / or It is preferable to reduce the arithmetic average roughness Ra, but it is necessary to have fine irregularities. Therefore, as a measure of having a fine surface irregularity shape, the arithmetic average inclination angle Δa is preferably 0.3 ° or more, and the arithmetic average roughness Ra is preferably 30 nm or more.

<How to adjust the surface shape>
The optical films 30 and 40 employed in the present invention have the specific surface shape described above. The surface shape itself is used, for example, to prevent reflection of external light and glare due to surface unevenness. It is well known in the field of antiglare films, and the surface shapes of the coating layers 32 and 42 may be adjusted according to them. As an example of surface shape adjustment, when using a coating liquid containing translucent fine particles, the design of the coating liquid, that is, the particle size of the fine particles, the resin constituting the coating layer, for example, active energy ray curing There are methods for adjusting the amount of fine particles added to the functional resin, the thickness of the coating layer, the solvent, the drying conditions, and the like. Further, when the surface shape is transferred by pressing a mold having a surface irregularity shape against a resin coating layer, a mold having a predetermined surface shape may be employed as the mold.

<Optical properties of optical film>
In the optical films 30 and 40 defined in the present invention, when the internal haze is imparted for the purpose of reducing glare as described above, the internal haze can be, for example, more than 20%, and usually 40%. It is preferable to make the following degree. On the other hand, when high transparency is required, the total haze of the optical films 30 and 40 is preferably 3% or less. The haze is divided into an external haze caused by surface irregularities of the film and an internal haze caused by an interface between substances having different refractive indexes existing inside the film. The optical films 30 and 40 defined in the present invention have a certain degree of external haze because fine irregularities are provided on the coating layers 32 and 42 side, but high transparency is required. The external haze is preferably 3% or less.

  The haze of the film can be measured using a commercially available haze meter, and the haze measured with the film as it is or with a smooth surface attached to a transparent glass substrate is the total haze. In addition, in order to cancel the influence of the surface unevenness, the haze measured in a state where a transparent adhesive is pasted on the uneven surface or immersed in an organic liquid having almost the same refractive index together with the film having the surface unevenness, Since the internal haze is obtained, the external haze can be obtained as a value obtained by subtracting the internal haze from the total haze.

[Method for producing optical film]
As described above, the optical film employed in the present invention removes the solvent after applying a coating liquid in which translucent fine particles are blended in a translucent resin on the transparent supports 31 and 41 (thermoplastic). If resin is used), or if necessary, dry to remove the solvent, irradiation with active energy rays (when using active energy ray curable resin) or heating (when using thermosetting resin or metal alkoxide) Thus, the resin is cured, and the unevenness based on the translucent fine particles is expressed on the coating layers 32 and 42, or the coating liquid containing the translucent resin is applied on the transparent supports 31 and 41. And it can manufacture by the method etc. which closely_contact | adhere the type | mold (embossing type | mold) which has an unevenness | corrugation to the application layer, and transcribe | transfer the uneven surface to an application layer.

Among these, the latter method is preferable. Then, next, the method of manufacturing the optical film prescribed | regulated by this invention by transferring an unevenness | corrugation to the coating layer of translucent resin using an emboss type | mold is demonstrated. Even when the unevenness is transferred using an embossing mold, it is possible to mix translucent fine particles in the coating liquid for forming the coating layers 32 and 42. This method basically undergoes the following steps (A) and (B).
(A) A step of applying a coating liquid containing a translucent resin on the transparent supports 31 and 41, and
(B) The process of transferring the uneven | corrugated surface of a transfer type | mold (emboss type | mold) to the surface of the layer to which the said coating liquid was apply | coated.

  The coating liquid used in the step (A) includes a light-transmitting resin or a resin forming the same (for example, an ionizing radiation curable resin, a thermosetting resin, or a metal alkoxide). In addition, other components such as a solvent are included as necessary. In the case where an ultraviolet curable resin is used as the resin that forms the translucent resin, the coating liquid further contains a photopolymerization initiator (radical polymerization initiator). Examples of the photopolymerization initiator include acetophenone photopolymerization initiator, benzoin photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone photopolymerization initiator, triazine photopolymerization initiator, and oxadiazole photopolymerization initiator. An initiator or the like is used. Also, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 10- Butyl-2-chloroacridone, 2-ethylanthraquinone, benzyl, 9,10-phenanthrenequinone, camphorquinone, methyl phenylglyoxylate, titanocene compounds, and the like can also be used as a photopolymerization initiator. The usage-amount of a photoinitiator is 0.5-20 weight part normally with respect to 100 weight part of ultraviolet curable resin contained in a coating liquid, Preferably it is 1-5 weight part. In the case of using a coating liquid containing translucent fine particles, the dispersion of the translucent fine particles in the coating liquid is isotropically dispersed in order to make the optical properties and surface shape of the obtained optical films 30 and 40 uniform. It is preferable that

  Application of the coating liquid onto the transparent supports 31 and 41 is performed by, for example, a gravure coating method, a micro gravure coating method, a rod coating method, a knife coating method, an air knife coating method, a kiss coating method, or a die coating method. Can do.

  Various surface treatments may be applied to the coated surfaces of the transparent supports 31 and 41 for the purpose of improving the coating properties of the coating liquid or improving the adhesion to the resulting coating layers 32 and 42. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, acid surface treatment, alkali surface treatment, and ultraviolet irradiation treatment. Further, another layer such as a primer layer may be formed on the transparent supports 31 and 41, and a coating solution may be applied thereon.

  The optical film 30 disposed on the display element side substrate 10 may function as a protective film for a polarizing film. In this case, in order to improve the adhesion between the transparent support 31 and the polarizing film, the surface of the transparent support 31 (the surface opposite to the coating layer 32) is hydrophilized by various surface treatments. Is preferred.

  In the said process (B), the uneven | corrugated surface of a metal mold | die is transcribe | transferred to the surface of the layer obtained by apply | coating the coating liquid demonstrated above. Specifically, the uneven surface of a mold having an uneven surface (embossed type) is brought into close contact with the surface of the layer obtained by applying the coating liquid, and the uneven surface is transferred. By thus transferring the embossed uneven surface to the surface of the coating layer, the coating layers 32 and 42 having a desired surface shape can be formed.

  When using an active energy ray curable resin, a thermosetting resin or a metal alkoxide as a resin for forming a translucent resin, after forming a coating layer from the above coating liquid and drying to remove the solvent if necessary By applying an active energy ray (when using an active energy ray curable resin) or heating (when using a thermosetting resin or a metal alkoxide) with an embossed uneven surface in close contact with the surface of the coating layer The coating layer is cured. The active energy ray can be appropriately selected from an electron beam, an ultraviolet ray, a near ultraviolet ray, a visible light, a near infrared ray, an infrared ray, an X-ray and the like according to the type of resin contained in the coating liquid. Among these, ultraviolet rays or electron beams are preferable, and ultraviolet rays are preferably used because they are easy to handle and high energy is obtained.

  When ultraviolet rays are employed, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, or the like can be used. An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used. Among these, mercury lamps, xenon lamps, or metal halide lamps including ultra-high pressure, high pressure, medium pressure and low pressure are preferably used.

  Further, as an electron beam, 50 to 1,000 keV emitted from various electron beam accelerators such as a cockroft Walton type, a bandegraph type, a resonance transformation type, an insulating core transformation type, a linear type, a dynamitron type, or a high frequency type. An electron beam having an energy of 100 to 300 keV is preferable.

  Next, the preferable form of the method to manufacture the optical film prescribed | regulated by this invention is demonstrated with reference to FIG. This preferable form is a step of continuously feeding the transparent support 31 wound in a roll shape, applying a coating liquid containing a translucent resin to the surface of the sent transparent support 31, and drying as necessary. A step of curing, a step of curing the layer formed by application of the coating liquid, and a step of winding up the optical film 30 obtained.

  In FIG. 4, a solid single arrow means the traveling direction of the film. First, the transparent support 31 is continuously unwound from the unwinding roll 60. Next, the coating liquid is applied onto the unwound transparent support 31 using the coating means 61 and the backup roll 62 facing the coating means 61. When a solvent is contained in the coating liquid, it is then dried by passing through a dryer 63. The transparent support 31 provided with the coating layer of the coating liquid is wound between the embossing roll 64 and the nip roll 65 so that the coating layer is in close contact with the embossing roll 64. Thereby, the uneven surface of the embossing roll 64 is transferred to the surface of the coating layer. Next, in a state where the transparent support 31 on which the coating layer is formed is wound around the embossing roll 56, the coating layer is cured by irradiating ultraviolet rays from the ultraviolet irradiation means 66, 66 through the transparent support 31. . Since an irradiation surface becomes high temperature by ultraviolet irradiation, it is preferable that the embossing roll 64 includes a cooling means for adjusting the surface temperature between room temperature and about 80 ° C. therein. Only one ultraviolet irradiation means 66 or a plurality of ultraviolet irradiation means 66 may be arranged. FIG. 4 shows an example in which two ultraviolet irradiation means 66 are arranged. The optical film 30 on which the coating layer has been formed is peeled off from the embossing roll 64 by the peeling roll 67. The optical film 30 thus manufactured is taken up by a take-up roll 69. In FIG. 4, after the peeling roll 67, the pinch roll 68 provided in front of the take-up roll 69 is made movable as shown by the broken line double arrows so that no slack or excessive tension is applied to the film. ing. The obtained optical film 30 is wound up with a protective film made of polyethylene terephthalate, polyethylene, or the like attached to the surface of the coating layer via a pressure-sensitive adhesive layer having removability for the purpose of protecting the coating layer. Also good.

  After the optical film 30 on which the coating layer is formed is peeled off from the embossing roll 64 by the peeling roll 67, additional ultraviolet irradiation may be performed. Further, instead of performing ultraviolet irradiation in a state of being wound around the embossing roll 64, the transparent support 31 having a layer coated with an uncured coating liquid is peeled off from the embossing roll 64 and then irradiated with ultraviolet light. A method of curing can also be adopted.

[Embossed molding method]
A mold (embossing mold) used for transferring the surface irregularity shape to the coating layers 32 and 42 has a surface shape corresponding to a shape desired for the optical films 30 and 40. The embossed surface shape can be transferred to the surface of the coating layer by curing the coating layer while pressing the surface shape against the surface of the coating layer containing the translucent resin.

  The uneven pattern in the embossed pattern may be a regular pattern, a random pattern, or a pseudo-random pattern in which one or more types of random patterns of a specific size are spread. However, from the viewpoint of preventing the reflected image from becoming iridescent due to interference of reflected light caused by the surface shape, a random pattern or a pseudo-random pattern is preferable.

  The outer shape of the embossed mold is not particularly limited, and may be a flat plate shape or a cylindrical or cylindrical roll, but it is shown in FIG. 4 from the viewpoint of continuous productivity. Such a columnar or cylindrical mold, that is, an embossing roll is preferable. In this case, a predetermined surface shape is formed on the side surface of the columnar or cylindrical mold.

  The base material constituting the embossing mold is not particularly limited, and can be appropriately selected from, for example, metal, glass, carbon, resin, or a composite thereof, but metal is preferable from the viewpoint of workability. The metal material suitably used for the embossing mold is aluminum, iron, or an alloy mainly composed of aluminum or iron, particularly from the viewpoint of cost.

  The embossing mold can be obtained by, for example, polishing the substrate, sandblasting, and then applying electroless nickel plating (Japanese Patent Laid-Open No. 2006-53371); applying copper plating or nickel plating to the substrate. Then, polishing, then sandblasting, and further chromium plating (Japanese Patent Laid-Open No. 2007-187952); after copper plating or nickel plating, polishing, then sandblasting, and further etching step Alternatively, a method of performing chrome plating after passing through a copper plating step (Japanese Patent Laid-Open No. 2007-237541); applying copper plating or nickel plating to the surface of the substrate, polishing, and then applying a photosensitive resin film to the polished surface Then, the pattern is exposed on the photosensitive resin film, then developed, and etched using the developed photosensitive resin film as a mask to remove the photosensitive resin film. Further, after etching and dulling the uneven surface, a method of applying chromium plating to the formed uneven surface (Example 1 of JP 2010-76385 A or JP 2012-68474 A); lathe For example, a method of cutting a base material to be a mold with a cutting tool using a machine tool (International Publication No. 2007/077892 pamphlet) or the like may be used.

  Embossed surface irregularities consisting of random patterns or pseudo-random patterns include, for example, FM screen method, DLDS (Dynamic Low-Discrepancy Sequence) method, method using micro phase separation pattern of block copolymer, band pass filter method It is possible to form a random pattern formed by, for example, exposing a photosensitive resin film on the photosensitive resin film, developing the random pattern, and performing an etching process using the developed photosensitive resin film as a mask.

[Touch panel]
The optical films 30 and 40 obtained as described above are applied as a Newton ring prevention film in a touch panel. This touch panel is configured as shown in FIG. 1 or 2 described above. For example, as shown in FIG. 1, the transparent electrodes of the resistive film type touch panel are formed by further forming transparent conductive films 15 and 25 on the coating layers 32 and 42 constituting the uneven surfaces of the optical films 30 and 40. Can be used as a board. The transparent conductive films 15 and 25 can be made of well-known ITO (indium tin oxide) or the like in a resistive film type touch panel. In addition, as shown in FIG. 2, optical films 30 and 40 may be applied to surfaces facing each of the display element side substrate 10 and the touch input element 20 in the capacitive touch panel.

  In any case, by arranging the optical films 30 and 40, when touch input is performed by pressing the touch input element 20 of the touch panel with a finger or the like, between the display element side substrate 10 and the touch input element 20. It is possible to effectively prevent Newton's rings, which are likely to occur with changes in the length (distance) of the existing gap 50, and to prevent deterioration in display quality. In both of the resistance film method and the capacitance method, as shown in FIG. 1 (c) and FIG. 2 (c), by providing the optical films 30 and 40 defined in the present invention on both sides of the gap, Generation of Newton rings can be effectively prevented.

[Touch input image display device]
In the touch input type image display device of the present invention, the touch panel described above is arranged on the viewing side of the image display element. The image display element can be composed of a liquid crystal cell or an organic EL display element. FIG. 5 is a schematic cross-sectional view showing an example of a touch input type image display device according to the present invention. In this example, the capacitive touch panel shown in FIG. Has been applied. In FIG. 5, reference numeral 70 is assigned to the entire touch panel shown in FIG. In this example, the display element side substrate 10 also serves as a front side (viewing side) polarizing plate 73 in the liquid crystal display device.

  As described above, in this example, the liquid crystal cell 71 is employed as the image display element, and the touch panel 70 having the front polarizing plate 73 is disposed on the viewing side. The liquid crystal cell 71 sandwiches a liquid crystal layer between two transparent substrates and controls the alignment state of the liquid crystal layer by applying a voltage to enable display. A liquid crystal cell that is well known in the field of liquid crystal display is adopted. be able to. When the liquid crystal cell is used as an image display element in this manner, the back side polarizing plate 74 is disposed on the back side, and the backlight 76 for supplying display light is disposed on the back side.

  Even if the touch panel shown in (a), (b) or (c) of FIG. 1 or (b) or (c) of FIG. 2 is arranged instead of the touch panel 70 in FIG. An image display device can be obtained.

  On the other hand, when an organic EL display element is employed as the image display element, the organic EL display element is a self-luminous type, and therefore, instead of the liquid crystal cell 71, the back side polarizing plate 74 and the backlight 76 in FIG. May be arranged. In this case, as described above, the display element side substrate 10 can be formed of a polarizing plate or a transparent substrate other than the polarizing plate. The organic EL display element includes a light emitter including an organic light emitting material sandwiched between a pair of electrodes, and a well-known one in this field can also be employed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.

[Example 1]
(A) Production of optical film (A1) Production of mold for optical film In accordance with the method described in Example 1 (B) of JP 2012-68474 A, the etching amount for forming irregularities is changed. And the metal mold | die for providing an uneven | corrugated shape to an optical film was produced. That is, first, an aluminum roll having a diameter of 200 mm (A5056 according to JIS) having a copper ballad plated thereon was prepared. The copper ballad plating was composed of a copper plating layer / thin silver plating layer / surface copper plating layer, and the total plating layer thickness was about 200 μm. The copper plating surface was mirror-polished, a positive photosensitive resin was applied to the polished copper plating surface, and dried to form a photosensitive resin film. Next, the photosensitive resin film was exposed to laser light so that a predetermined pattern (the pattern shown in FIG. 16 of the same publication) was repeated, and then developed. Laser light exposure and development were performed using “Laser Stream FX” manufactured by Sink Laboratories.

  After the development, a first etching process was performed with a cupric chloride aqueous solution. Next, the photosensitive resin film was removed from the roll after the first etching treatment, and a second etching treatment was again performed with a cupric chloride aqueous solution. At this time, in order to adjust the skewness Psk and arithmetic mean inclination angle Δa of the cross-sectional curve of the optical film obtained by the subsequent processing to predetermined values, the first etching processing amount (thickness cut by etching) is 4 μm, The amount of etching treatment No. 2 (also the thickness cut by etching) was set to 12 μm. Thereafter, chrome plating was performed. The thickness of the chrome plating was set to 4 μm. Thus, a mold roll having fine irregularities on the surface was produced.

(A2) Preparation of UV curable resin composition The following were prepared as raw materials for the UV curable resin composition.
UV curable resin: a mixture of 60 parts of pentaerythritol triacrylate and 40 parts of polyfunctional urethanized acrylate (reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate).
Photopolymerization initiator: “Lucirin TPO” (chemical name: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) sold by BASF.

  To 100 parts of the ultraviolet curable resin, 5 parts of the photopolymerization initiator and 150 parts of ethyl acetate as a diluent solvent were mixed to prepare an ultraviolet curable resin composition for forming a coating layer.

(A3) Production of optical film The ultraviolet curable resin composition prepared above was coated on a transparent support made of a triacetyl cellulose film with a die coater so that the film thickness after drying was 5 μm, and the transparent support was prepared. And a laminate composed of a coating layer of the ultraviolet curable resin composition was obtained. After drying this laminated body in a drying furnace, it was pressed and adhered to the mold roll produced in (A1) above with a nip roll so that the coating layer side was in contact with the mold. In this state, the ultraviolet curable resin composition was cured by irradiating ultraviolet rays from the transparent support side so that the maximum illuminance was 700 mW / cm ² and the integrated light amount was 300 mJ / cm ² . Thereafter, the laminate was peeled off from the mold roll to produce an optical film having a coating layer having irregularities on the surface.

(B) Measurement of surface shape of optical film
Using the SENSOFAR 3D microscope “PLμ 2300”, the objective lens magnification is 50 times, and the confocal mode, the surface shape of the optical film obtained above (the absolute value of the skewness Psk of the cross-sectional curve, arithmetic The average inclination angle Δa and the arithmetic average roughness Ra) were determined. The measurement area was 255 μm × 185 μm. In addition, in order to prevent the sample from warping, an optically transparent adhesive is used, and the surface opposite to the concave / convex surface of the optical film is bonded to the glass substrate (the concave / convex surface becomes the surface) and measured. Went. As a result, the absolute value of the skewness Psk of the cross-sectional curve was 0.187, the arithmetic average inclination angle Δa was 0.52 °, and the arithmetic average roughness Ra was 65 nm.

(C) Measurement of optical properties (haze) of optical film Using an optically transparent adhesive, the surface opposite to the concavo-convex surface of the optical film obtained above is bonded to a glass substrate, and JIS K 7136: 2000 “Haze meter“ HM-150 ”manufactured by Murakami Color Research Laboratory Co., Ltd. Asked for all haze. Moreover, the transparent adhesive layer side of the triacetyl cellulose film in which the transparent adhesive layer is formed is bonded to the uneven surface of the film bonded to the glass substrate in the same manner as above, and the transmitted light is scattered by the uneven surface (external About the film of the state which eliminated the haze, the haze by internal scattering (internal haze) was measured with the same haze meter as above, and the external haze of the optical film was determined by subtracting the value of the internal haze from the total haze. As a result, the total haze was 0.7% and the external haze was 0.5%.

(D) Production of Polarizing Film A polyvinyl alcohol film having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30 ° C., and then iodine / potassium iodide / Dyeing was performed by dipping in an aqueous solution having a water weight ratio of 0.02 / 100 at 30 ° C. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. for crosslinking. Subsequently, the film was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizing film in which iodine is adsorbed and oriented on polyvinyl alcohol. Stretching was mainly performed in the steps of iodine dyeing and boric acid crosslinking treatment, and the total stretching ratio was 5.3 times.

(E) Preparation of Polarizing Film Adhesive Separately, 1.8 parts of carboxyl group-modified polyvinyl alcohol “Kuraray Poval KL318” (modified degree 2 mol%) sold by Kuraray Co., Ltd. per 100 parts of water Dissolve, and then add 1.5 parts of “Smiles Resin 650” (aqueous solution with a solid content of 30%) sold by Sumika Chemtex Co., Ltd., which is a water-soluble polyamide epoxy resin. An alcohol-based adhesive was prepared.

(F) Production of polarizing plate (display element side substrate provided with optical film) Triacetyl cellulose film on the side opposite to the surface on which the coating layer having the irregularities of the optical film produced in (A3) above is formed After subjecting the surface to saponification treatment, the polyvinyl alcohol-based adhesive prepared in (E) above was applied with a 10 μm bar coater, and the polyvinyl alcohol-iodine polarizing film prepared in (D) above was applied thereon. Pasted. Moreover, as a transparent protective film to be bonded to the other surface of the polyvinyl alcohol-iodine polarizing film, a 40 μm thick triacetyl cellulose film (“KC4UE” sold by Konica Minolta Advanced Layer Co., Ltd., 40 μm thick, Ro = 0.7 nm, Rth = -0.1 nm). After the saponification treatment is applied to this protective film, the polyvinyl alcohol-based adhesive prepared in (C) above is applied to the saponification treated surface with a 10 μm bar coater, and the coated surface is coated with the optical film of the upper polarizing film. It bonded on the surface on the opposite side to the surface where the film was bonded. Thereafter, it was dried at 80 ° C. for 5 minutes and further cured at room temperature for 1 day. Thus, a polarizing plate having a layer structure of (uneven surface) optical film / polyvinyl alcohol-iodine polarizing film / triacetyl cellulose film was produced.

(G) Evaluation of Newton's ring (G1) Single layer configuration A glass substrate provided with a capacitive touch panel on the uneven surface side of the optical film of the polarizing plate produced in (F) above, the glass substrate and the polarizing plate The gap between them was adjusted to be 0.3 mm. We pressed the touch panel with fingers to observe whether Newton rings occurred. This touch panel has a configuration shown in FIG.
(G2) Two-layer configuration On one side of a glass substrate equipped with a capacitive touch panel, the optical film produced in (A3) above is used with an acrylic transparent adhesive so that the uneven surface is on the outside. Pasted. Next, the uneven surface of the polarizing plate prepared in (F) above and the optical film bonding surface of the glass substrate face each other, and the gap between the glass substrate and the polarizing plate is 0. Adjusted to be 3 mm. The touch panel was pressed with a finger and observed whether Newton rings occurred. This touch panel has a configuration shown in FIG.

(G3) Evaluation criteria Each result was evaluated in the following three stages.
○: Newton ring is not observed.
Δ: Newton ring is slightly observed, but at a level where there is no problem in visual recognition.
X: Newton ring is observed remarkably.

[Comparative Example 1]
In this example, the antiglare film “NC-1” sold by Nippon Paper Chemicals Co., Ltd. was used as the optical film. When the surface shape of this film was measured by the same method as in Example 1, the absolute value of the skewness Psk of the cross-sectional curve was 0.559, the arithmetic average inclination angle Δa was 0.57 °, and the arithmetic average roughness Ra was 61 nm. It was. When the haze of this film was measured by the same method as in Example 1, the total haze was 0.8% and the external haze was 0.5%. A polarizing plate was produced in the same manner as in Example 1 except that this film was used. The Newton ring was evaluated in the same manner as in Example 1 for each of the single-layer structure and the two-layer structure.

  The evaluation results of Newton rings performed in Example 1 and Comparative Example 1 are shown in Table 1 together with the physical properties of the optical film used.

10: Display element side substrate,
15 …… Transparent conductive layer,
20 …… Touch input element,
25 …… Transparent conductive layer,
30, 40 ... Optical film,
31, 41 ... Transparent support,
32, 42 ... coating layer,
50 …… Gap,
60: Unwinding roll,
61 …… Coating means,
62 …… Backup roll,
63 …… Dryer,
64 …… Emboss roll,
65 …… Nip roll,
66 …… UV irradiation means,
67 …… Peeling roll,
68 …… Moveable pinch roll,
69 …… Take-up roll,
70 …… Touch panel,
71: Liquid crystal cell (image display element),
73 …… Front side polarizing plate,
74 …… Back side polarizing plate,
76 …… Backlight.

Claims (9)

The display element side substrate and the touch input element are arranged with a gap,
At least one of the gap side surface of the display element side substrate and the gap side surface of the touch input element has a transparent support, and the absolute value of the skewness Psk of the cross-sectional curve formed thereon is 0.3 or less. An optical film comprising a coating layer having a fine surface irregularity shape is disposed with the coating layer side facing the gap ,
The optical film has a total haze of 0.8% or less .   The touch panel according to claim 1, wherein the optical film is disposed only on a gap-side surface of the display element side substrate.   The touch panel according to claim 1, wherein the optical film is disposed on each of a gap side surface of the display element side substrate and a gap side surface of the touch input element.   The touch panel according to claim 2 or 3, wherein the display element side substrate is a polarizing plate, and the optical film is disposed on a surface thereof.   The touch panel according to claim 1, wherein the coating layer of the optical film has a surface shape with an arithmetic average inclination angle Δa of 1 ° or less.   The touch panel according to claim 1, wherein the coating layer of the optical film has a surface shape with an arithmetic average roughness Ra of 100 nm or less. The optical film, external haze is 3% or less, the touch panel according to any one of claims 1-6. Wherein on the optical film, a touch panel according to any one of claims 1 to 7 having a transparent conductive layer. A touch input-type image display device comprising: an image display element; and the touch panel according to any one of claims 1 to 8 disposed on a viewing side thereof.

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