Laminate, manufacturing method thereof, and display device

Abstract

To provide a method for evaluating fingerprint resistance, which is applicable to an on-vehicle display device, a laminate excellent in the fingerprint resistance satisfying an evaluation standard by the evaluation method, a manufacturing method thereof, and a display device having the laminate.SOLUTION: Disclosed is a method for evaluating fingerprint resistance of the surface of an object, in which a measurement value difference Δ L*(θ) between a portion on the surface of the object to which artificial fingerprint liquid has been transferred and a portion to which it has not been transferred, which is determined by an equation (1) defined in the specification using a variable angle colorimeter, is used. Provided are a laminate which has the surface on which the Δ L*(θ) is 0.1 or less, a manufacturing method thereof, and a display device having the laminate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a method for evaluating fingerprint resistance, a laminate, a method for manufacturing the same, and a display device. [Background technology]

[0002] In recent years, there has been an increasing need to operate various electronic devices by physically touching display devices such as touch panel displays with one's fingers. To prevent a decrease in display image performance due to fingerprints, such display devices require fingerprint resistance.

[0003] Furthermore, the surface of in-vehicle display devices is usually treated with various processes such as anti-glare, anti-reflection, and anti-fingerprint coatings to suppress the effects of reflections from sunlight, etc. However, these processes can sometimes make fingerprints more noticeable and reduce fingerprint resistance.

[0004] As a method for evaluating fingerprint resistance, Patent Document 1 describes the process of applying a diluted oleic acid solution to the surface of the object to be evaluated and then comparing the results with CIE1976L * a * b * Lightness L measured by a simultaneous photometric spectrophotometer specified by the display system * The technology that uses this as an indicator is disclosed. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-34416 [Overview of the project] [Problems that the invention aims to solve]

[0006] When display devices are used inside vehicles, such as in-vehicle display devices, the evaluation results obtained using the evaluation method described in Patent Document 1 may differ from the results of sensory evaluations by humans inside the vehicle, indicating that the evaluation method itself may not be able to reproduce the actual in-vehicle environment. In this context, since users typically wipe the display screen if fingerprints or other marks are present, developing a method for evaluating fingerprint resistance after wiping the surface of an in-vehicle display device is also extremely important.

[0007] Therefore, the object of the present invention is to provide a method for evaluating fingerprint resistance that takes into account wipeability and is applicable to in-vehicle display devices, a laminate with excellent fingerprint resistance that satisfies the evaluation criteria of the evaluation method, a method for manufacturing the same, and a display device having the laminate. [Means for solving the problem]

[0008] The present invention provides a method for evaluating fingerprint resistance, a laminate, a method for manufacturing the same, and a display device having the following configurations [1] to

[12] . [1] A method for evaluating the fingerprint resistance of an object surface, wherein the difference in measured values ​​ΔL is determined by the following formula (1) using a variable angle colorimeter between an area on the object surface that has been wiped off after an artificial fingerprint solution has been transferred and an area that has not been transferred. * A method for evaluating fingerprint resistance, characterized by using (θ): Formula (1) ΔL * (θ) = L of the area wiped after artificial fingerprint transfer * -L of the non-transferable area of ​​the artificial fingerprint solution * However, the angle of incidence of light shall be -70° with respect to the normal to the surface of the object, and the measurement angle shall be -5° with respect to the normal to the surface of the object. [2] The evaluation method according to [1], wherein the method for transferring the artificial fingerprint solution involves applying the artificial fingerprint solution to a transfer substrate by a spin coating method to produce a transfer foil having a haze value of 7±2%, pressing a simulated finger against the transfer foil with a load of 60N, and then pressing the simulated finger against the surface of the object with a load of 60N for 2 seconds. [3] The evaluation method according to [1] or [2], wherein when evaluating the fingerprint resistance of the surface of the object, the squalene adhesion amount on the surface of the object is further used. [4] The measurement value difference ΔL obtained from the following formula (1) by a variable-angle colorimeter between a site wiped once after the artificial fingerprint liquid is transferred and a site where the artificial fingerprint liquid is not transferred: * A laminate having a surface with (θ) of 0.1 or less: Formula (1) ΔL * (θ) = L of the wiped part after the transfer of the artificial fingerprint liquid * - L of the non-transferred part of the artificial fingerprint liquid * However, the light incident angle is -70° with respect to the normal of the surface of the measurement object, and the measurement angle is -5° with respect to the normal of the surface of the measurement object. [5] A laminate having a base material, a predetermined layer disposed on the base material, and a outermost layer disposed on the predetermined layer, The predetermined layer includes a first predetermined layer on the base material side and a second predetermined layer on the outermost layer side, The laminate according to [4], wherein the refractive index of the first predetermined layer is 2.00 or less. [6] A laminate having a base material, a predetermined layer disposed on the base material, and a outermost layer disposed on the predetermined layer, The predetermined layer includes a first predetermined layer on the base material side and a second predetermined layer on the outermost layer side, The laminate according to [4] or [5], wherein the refractive index of the second predetermined layer is 1.43 or more and 1.49 or less. [7] On the surface of the laminate, the angle dependence of ΔL * (θ) has a negative peak in the specular reflection region and a positive peak at angles other than the specular reflection region, The laminate according to any one of [4] to [6], wherein the squalene adhesion amount on the surface of the laminate after the artificial fingerprint liquid is transferred and before being wiped is less than 40 μg. [8] On the surface of the laminate, the angle dependence of ΔL * (θ) does not have a positive peak at angles other than the specular reflection region, the laminate according to any one of [4] to [6]. [9] The laminate according to [8], wherein the outermost layer is arranged on a second predetermined layer, and the distance from the surface of the outermost layer to the second predetermined layer is 60 nm or less.

[10] The laminate according to any one of [4] to [9], wherein the method for transferring the artificial fingerprint solution involves attaching the artificial fingerprint solution to a transfer substrate by a spin coating method to produce a transfer foil having a haze value of 7±2%, pressing a simulated finger against the transfer foil with a load of 60N, and then pressing the simulated finger against the surface of the laminate with a load of 60N for 2 seconds. A display device characterized by having a laminate as described in any of

[11] [4] to

[10] .

[12] On the surface of the laminate, the difference in measured values ​​ΔL obtained by the following formula (1) using a variable angle colorimeter between an area where the artificial fingerprint solution has been transferred and then wiped off and an area where the solution has not been transferred. * A method for manufacturing a laminate, characterized by manufacturing the laminate such that (θ) is 0.1 or less: Formula (1) ΔL * (θ) = L of the area wiped after artificial fingerprint transfer * -L of the non-transferable area of ​​the artificial fingerprint solution * However, the angle of incidence of light shall be -70° with respect to the normal to the surface of the object being measured, and the measurement angle shall be -5° with respect to the normal to the surface of the object being measured. [Effects of the Invention]

[0009] The present invention provides a method for evaluating fingerprint resistance that takes into account wipeability and is applicable to in-vehicle display devices, a laminate with excellent fingerprint resistance that satisfies the evaluation criteria of the evaluation method, a method for manufacturing the same, and a display device having the laminate. [Brief explanation of the drawing]

[0010] [Figure 1] (a) is a schematic plan view showing how sunlight is shone on the display device from outside the vehicle, either directly or through glass, and (b) is a schematic diagram showing the angle of incidence and measurement angle of sunlight on the display device. [Figure 2]This graph shows an example of the correlation between the ΔL*(θ) value and the user's sensory evaluation results. [Figure 3] This graph shows an example of the correlation between the ΔL*(SCI) value and the results of sensory evaluations by users. [Figure 4] This graph shows an example of the angular dependence of ΔL*(θ) at a light incidence angle of -70° in a laminated material, after artificial fingerprint solution transfer and before the wiping operation. [Figure 5] This graph shows another example of the angular dependence of ΔL*(θ) at a light incidence angle of -70° in a laminate after artificial fingerprint solution transfer and before the wiping operation. [Modes for carrying out the invention]

[0011] In the evaluation method described in Patent Document 1, the CIE1976L of the surface of the object to be evaluated is measured before and after application of the diluted oleic acid solution. * a * b * Brightness L as defined by the display system * The fingerprint resistance of the object being evaluated is assessed using this as an indicator. In addition, Patent Document 1 describes the brightness L * A simultaneous photometric spectrophotometer is used for the measurement, and furthermore, sensory evaluation under three-wavelength fluorescent lighting is used to evaluate the accuracy of the evaluation method. However, under these conditions, the angle of incidence and the measurement angle are not defined, so it is not possible to evaluate the fingerprint resistance of the display device in the in-vehicle environment, and there were discrepancies between the evaluation results obtained by the method in Patent Document 1 and the sensory evaluation results in the actual vehicle. Furthermore, the evaluation method described in Patent Document 1 uses a diluted oleic acid solution obtained by dissolving oleic acid in ethanol to evaluate fingerprint resistance, but the adhesion state of this diluted solution to the display device sometimes differed from that of actual fingerprints. In particular, for display devices equipped with an oil-repellent coating, it was sometimes difficult to accurately evaluate fingerprint resistance due to the effect of droplet repellency of the diluted oleic acid solution. Furthermore, in the evaluation method described in Patent Document 1, a diluted oleic acid solution is applied using a finger cot to evaluate fingerprint resistance. However, in this method, it was sometimes not possible to apply a simulated fingerprint with good reproducibility.

[0012] On the other hand, the fingerprint resistance evaluation method of the present invention is similar to the method described in Patent Document 1, and CIE1976L * a * b * Brightness L as defined by the display system * Although a simultaneous photometric spectrophotometer is used as the measuring device, a variable-angle colorimeter that applies specific light incidence angles and measurement angles is used. Thus, in this invention, assuming an in-car environment, and considering the position of the sun, the position of the display device, and the viewpoint of the user such as the driver, the measurement conditions of the variable-angle colorimeter are set to incidence angle: -70° and measurement angle: -5°, and the variable-angle brightness L before and after application of artificial fingerprint solution, taking into account the wipeability, is measured. * The change in (θ) is used as an indicator of fingerprint resistance. Therefore, the present invention can provide a highly accurate method for evaluating fingerprint resistance (fingerprint visibility) that can obtain evaluation results equivalent to those obtained from sensory evaluations conducted inside actual vehicles. Furthermore, in this invention, instead of a diluted oleic acid solution, for example, a conventionally known artificial fingerprint solution can be used for evaluation. Some artificial fingerprint solutions take into account solid components such as dirt and sebum, and by using such an artificial fingerprint solution, it is possible to perform evaluations that take into account actual fingerprint adhesion more accurately than with a diluted oleic acid solution. In addition, by using such an artificial fingerprint solution containing solid components, the fingerprint resistance evaluation method of the present invention can be easily applied to display devices equipped with an oil-repellent coating. Furthermore, in this invention, since it is possible to evaluate fingerprint resistance after applying an artificial fingerprint solution using a specific transfer method and wiping it off, evaluation can be performed under conditions that more accurately reflect the actual vehicle environment.

[0013] The present invention will be described in detail below. However, the present invention is not limited to the following embodiments. Also, in order to clarify the explanation, the following description and drawings have been simplified as appropriate. In the following description, the "~" indicating a numerical range means that the numbers written before and after it are included as the lower and upper limits. Furthermore, (meth)acrylic acid means either methacrylic acid or acrylic acid, or both.

[0014] <Method for evaluating fingerprint resistance> The present invention's method for evaluating fingerprint resistance (hereinafter sometimes referred to as "this evaluation method") is a method for evaluating the fingerprint resistance of an object (object to be measured) surface after wiping, and the difference in measured values ​​ΔL obtained from the following formula (1) using a variable angle colorimeter between the area on the object surface that has been wiped after the artificial fingerprint solution has been transferred and the area that has not been transferred. * (θ) is used. Various materials can be used as the wiping material for the surface of the object, but for example, Scotch-Brite No. 5000 (product name, manufactured by 3M Japan) can be used. Formula (1) ΔL * (θ) = L of the area wiped after artificial fingerprint transfer * -L of the non-transferable area of ​​the artificial fingerprint solution * However, the angle of incidence of light shall be -70° with respect to the normal to the surface of the object, and the measurement angle shall be -5° with respect to the normal to the surface of the object.

[0015] As shown in Figure 1(a), this evaluation method assesses the visibility of fingerprints after wiping (fingerprint resistance) when light from a light source 1, such as the sun, is shone directly from outside the vehicle or through a light-transmitting object 2, such as glass, on the surface of a display device 3 mounted inside the vehicle, and the user visually inspects the display device in a vehicle environment. Furthermore, it is expected that fingerprint resistance under such conditions will be greatly affected by light shone through the windshield or side windows at an angle of 45° or more relative to the normal to the surface of the display device. In this evaluation method, as shown in Figure 1(b), in particular, the fingerprint resistance after wiping is evaluated when light from a light source 1, such as the sun, is shone at an incident angle of -70° relative to the normal N of the surface of the display device 3, and the user visually inspects the display device at an angle of -5° (measurement angle) relative to the normal, thereby obtaining evaluation results that more accurately reflect the fingerprint resistance of the display device after wiping in a vehicle environment.

[0016] In this evaluation method, from the viewpoint of obtaining excellent fingerprint resistance after wiping, the above ΔL * (θ) is preferably 0.1 or less, more preferably 0.10 or less, and even more preferably 0.0 or less. Also, ΔL * (θ) is preferable as small as possible. Note that ΔL * A value of (θ) of 0 means that the measurement values ​​obtained by the bevel colorimeter are the same (no difference) between the area on the surface of the object where the artificial fingerprint solution was transferred and then wiped off, and the area where it was not transferred. Therefore, ΔL * The closer (θ) is to 0, the better. Therefore, fingerprint wiping ability refers not to the physical removal of fingerprints, but to the fact that they are not optically visible (optical invisibility). ΔL * The detailed method for measuring (θ) will be described later.

[0017] The artificial fingerprint solution used in this evaluation method can be any conventionally known solution, but as mentioned above, one that takes into account solid components such as dirt and sebum is more preferable. Fingerprints are mainly composed of water and sebum components, and the proportion of sebum components increases as the water evaporates. Therefore, in most cases, it is acceptable to consider fingerprints as sebum. Components that make up sebum include, for example, fatty acids, glycerolipids, fatty acid esters, wax esters, cholesterol derivatives, and squalene. Examples of the aforementioned fatty acids include oleic acid, stearic acid, linolenic acid, palmitic acid, nonanoic acid, adipic acid, tridecanoic acid, myristoleic acid, tetradecanoic acid, and palmitoleic acid. Examples of glycerolipids include monoolein, trimiristin, monocaprylin, triolein, monolaurin, monopalmitin, monostearin, tristearin, tripalmitin, and tricaproin. Examples of the aforementioned fatty acid esters include butyl n-octanoate, benzyl octanoate, isobutyl decanoate, ethyl undecanoate, ethyl stearate, ethyl palmitate, ethyl pentadecanoate, benzyl laurate, amyl n-octanoate, and butyl myristate. Examples of the aforementioned wax esters include dodecyl stearate, decyl decanoate, hexadecyl palmitate, 3-isoamyl-6-methyl-2-heptyl myristate, myricyl palmitate, cecil palmitate, and myricyl cerotate. Examples of the cholesterol derivatives include cholesterol, 7-dehydrocholesterol, vitamin D, cholic acid, chenodeoxycholic acid, deoxycholic acid, lithocholic acid, progesterone, aldosterone, and cortisol. Furthermore, the artificial fingerprint solution may contain one or more particulate materials selected from inorganic fine particles such as silica fine particles, alumina fine particles, and iron oxide fine particles, as well as organic fine particles such as keratin fine particles, chitin fine particles, chitosan fine particles, acrylic fine particles, styrene fine particles, divinylbenzene fine particles, polyamide fine particles, polyimide fine particles, polyurethane fine particles, and melamine fine particles. The artificial fingerprint solution may also contain Kanto loam (JIS test powder 1) as a particulate material. The average particle size of the particulate material can be set as appropriate and is not particularly limited, but for example, the average particle size can be 0.05 μm or more and 100 μm or less. In addition, the artificial fingerprint solution may also contain thickeners such as carrageenan and gum arabic, and surfactants such as quaternary ammonium salts and alkylbenzene sulfonates. The blending ratio of each component constituting the artificial fingerprint solution can be set as appropriate within the range in which the effects of the present invention are obtained, and is not particularly limited. The artificial fingerprint solution used in this evaluation method can be diluted with an organic solvent as appropriate when preparing the thin film (transfer film). Any conventionally known organic solvent can be used, such as isopropyl alcohol, methyl ethyl ketone, methoxypropanol, or ethanol.

[0018] For example, the following formulations can be used as artificial fingerprint solutions. - An artificial fingerprint solution obtained by adding 1.0 g of triolein to 10 g of methoxypropanol as a diluent, and then adding 400 mg of Kanto loam (Type 11 test powder as defined in JIS Z8901) and stirring. - An artificial fingerprint solution obtained by adding 200 mg of triolein to 5 g of methoxypropanol as a diluent, then adding 200 mg of keratin (derived from human epithelium, manufactured by Wako Pure Chemical Industries, Ltd.), stirring vigorously, letting it stand for 10 seconds, and then gently collecting the supernatant portion that does not contain large-particle keratin.

[0019] Here, it is preferable to use an artificial fingerprint solution that can reproduce the fingerprint components described above. Specifically, in this invention, it is preferable to use an artificial fingerprint solution that is solid at 20°C and dispersed at 40°C. For example, by adding a substance (for example, one of the components that make up sebum described above) with a melting point higher than room temperature to the artificial fingerprint solution described above, an artificial fingerprint solution that is solid at 20°C and dispersed at 40°C can be produced. An artificial fingerprint solution having these properties adheres more easily to the coating surface than conventional oleic acid dilutions using oleic acid alone, can be used for evaluation that takes into account actual fingerprint adhesion, and has excellent adhesion and evaluation reproducibility.

[0020] Furthermore, when evaluating the amount of squalene adhering to the artificial fingerprint solution, it is preferable that the squalene content in the artificial fingerprint solution be 10 to 15% by mass, from the viewpoint of performing the evaluation appropriately.

[0021] It is known that the components and their ratios that make up sebum vary from person to person and with age. However, the refractive index of sebum should be between the minimum and maximum refractive indices of the components it contains. Among the above sebum components, the substance with the lowest refractive index is n-butyl octanoate, with a refractive index of 1.42. Among these sebum components, the substance with the highest refractive index is benzyl octanoate, with a refractive index of 1.49. Therefore, the refractive index of fingerprints is thought to be in the range of 1.42 to 1.49.

[0022] While conventionally known methods can be applied to the transfer method of the artificial fingerprint solution, the following method is preferable. Specifically, it is preferable to use a method in which the artificial fingerprint solution is attached to a transfer substrate by a spin coating method to create a transfer foil with a haze value of 7±2%, a simulated finger is pressed against the transfer foil with a load of 60N, and then the simulated finger is pressed against the surface of the target object with a load of 60N for 2 seconds. In this method, the artificial fingerprint solution is dropped onto a rotating transfer substrate by the spin coating method, and a uniform thin film is formed by centrifugal force, thus enabling the transfer of the artificial fingerprint solution with good reproducibility. Here, conventionally known materials can be used as the transfer substrate, but for example, a polycarbonate plate can be used. Also, conventionally known materials can be used as the simulated finger, but for example, natural rubber (rubber hardness: Shore E60, Shore E70 according to JIS K 6253 standard) can be used. Furthermore, as mentioned above, it is preferable to use an artificial fingerprint solution that is solid at 20°C and dispersed at 40°C.

[0023] Furthermore, this evaluation method can also utilize the difference in measured values ​​Δluminance, which is obtained by the following formula (2) using a luminance meter (e.g., product name: SR-UL1R, manufactured by Topcon Techno House Co., Ltd.) between areas on the display device surface where the artificial fingerprint solution has been transferred and then wiped off, and areas where the solution has not been transferred. Formula (2) ΔBrightness = Brightness of the area wiped after artificial fingerprint transfer - Brightness of the area not transferred with artificial fingerprint. However, the angle of incident light shall be 85° upward with respect to the normal to the surface of the measurement sample, the measurement angle shall be 25° upward and 30° to the right with respect to the normal to the surface of the measurement sample, the measurement distance shall be 650 mm, and the measurement range shall be 0.2° (solid angle). Furthermore, the wiping material and wiping conditions shall be as described above for ΔL * The same conditions as when measuring (θ) can be used. However, since measuring luminance is difficult to perform in a defined environment due to issues with installation angle and ambient light, and the evaluation is not highly reproducible, it is desirable to use the evaluation method of the present invention using a variable-angle colorimeter, or to use the evaluation of luminance and the evaluation of the present invention in combination.

[0024] In this evaluation method, from the viewpoint of obtaining excellent fingerprint resistance after wiping, the above Δ brightness is 0.1 [cd / m²]. 2 It is preferable that Δluminance and ΔL are less than or equal to Δluminance and ΔL. * A certain correlation can be observed between (θ) and Δluminance and ΔL. * By setting both (θ) and (θ) to good values, it is possible to provide better fingerprint resistance after wiping.

[0025] When evaluating the fingerprint resistance of the object surface after wiping, it is preferable to further use the amount of squalene (amount of fingerprint components) adhering to the object surface (for example, assuming fingerprints are present). In particular, if the object surface is oil-repellent, a squalene adhering amount of less than 40 μg results in less noticeable fingerprints and superior fingerprint resistance. A detailed method for measuring the squalene adhering amount will be described later.

[0026] <Laminate> The laminate of the present invention (hereinafter sometimes referred to as "this laminate") has a measurement difference ΔL in the evaluation method described above. * Because the surface has a (θ) of 0.1 or less, it exhibits excellent fingerprint resistance after wiping, and fingerprints adhering to the surface can be made less noticeable. Furthermore, it is preferable to use the spin-coating method described above for transferring the artificial fingerprint solution used in the evaluation. Furthermore, the laminate may comprise a base material, a predetermined layer disposed on the base material, and an outermost layer disposed on the predetermined layer. The predetermined layer may include a first predetermined layer on the base material side and a second predetermined layer on the outermost layer side. In addition, other layers (intermediate layers) may be present between the base material and the first predetermined layer, between the first predetermined layer and the second predetermined layer, between the outermost layer and the second predetermined layer, etc., to the extent that the effects of the present invention can be obtained. Examples of intermediate layers include a desired functional layer, an adhesive layer, an ultraviolet absorbing layer, an infrared absorbing layer, an anti-reflective layer, a soft (impact-resistant) layer, a hard coat layer, a conductive layer, an antistatic layer, a heat insulating layer, a reflective layer, and a primer layer. The outermost layer is placed in a situation where it comes into contact with human hands during use. The outermost layer may include, for example, an oil-repellent coating layer or an oil-lipophilic coating layer, as described later. The laminate may be used on the operating surface of a touch panel, or on the display surface of a display panel or on protective members such as cover panels that cover it. However, the applications of this laminate are not limited to these.

[0027] Here, the refractive index of the first predetermined layer is preferably greater than 1.49, more preferably 1.60 or greater, preferably 2.00 or less, and more preferably 1.80 or less, from the viewpoint of providing excellent fingerprint resistance after wiping. Furthermore, the refractive index of the second predetermined layer is preferably 1.43 or higher, more preferably 1.45 or higher, more preferably 1.49 or lower, and more preferably 1.47 or lower, from the viewpoint of providing excellent fingerprint resistance after wiping. As mentioned above, the refractive index of fingerprints is considered to be between 1.42 and 1.49, so it is more preferable that the refractive index of the second predetermined layer be close to its average value of 1.46. If the refractive index of the second predetermined layer is between 1.43 and 1.49, the interfacial reflectance between the fingerprint and the laminate surface will be reduced, the difference between the fingerprint-covered area and the other areas will be reduced, and the fingerprint will become less noticeable. Here, the refractive index of the substrate can be set as appropriate, but for example, a substrate with a refractive index of 1.50 can be used. The refractive index of each layer can be measured using an ellipsometer or the like.

[0028] The material constituting the substrate is not particularly limited, and conventionally known materials can be used as appropriate. For example, the substrate may be a transparent resin film or laminated film (laminated board) made of TAC (triacetylcellulose), PMMA (polymethyl methacrylate), PC (polycarbonate), PET (polyethylene terephthalate), etc., i.e., a resin substrate. Alternatively, a conventionally known glass substrate (glass substrate) may be used as the substrate.

[0029] Furthermore, the materials constituting the first predetermined layer, the second predetermined layer, and the outermost layer are not particularly limited, but may be composed of layers made of active energy ray curable resins or thermosetting resins, or of thin films obtained by, for example, vacuum deposition, sputtering, or wet coating of metal oxides (e.g., ZrO2, Al2O3, SiO2). These layers can be given different properties depending on the additives they contain and the type of resin they contain.

[0030] Furthermore, in this laminate, ΔL at an incident light angle of -70° * When the surface (outermost layer) has an oil-repellent coating whose angle dependence of (θ) has a negative peak in the specular reflection region and a positive peak at angles other than the specular reflection region, it is preferable that the amount of squalene adhering to the surface of the laminate after the artificial fingerprint solution has been transferred and before wiping (i.e., when it is assumed that a fingerprint has been attached) is less than 40 μg. For example, ΔL * The angular dependence of (θ) is calculated by taking the incident light angle as -70° and the measurement angle as -60° to +85°, and then determining ΔL for each angle. * This can be measured by calculating (θ). By satisfying these conditions, the ΔL*(θ) due to fingerprint adhesion can be reduced, making fingerprints less noticeable. If the outermost layer is oleophobic, its refractive index can be, for example, 1.30 to 1.50. The specular reflection region at a light incidence angle of -70° is set to +70 ± 10°. Here, Figure 4 shows the ΔL at a light incidence angle of -70° in a laminate having an oleophobic coating on its surface, after artificial fingerprint solution transfer and before wiping. *A graph showing an example of the angle dependence of (θ) is shown. In the graph shown in Figure 4, ΔL at an incident light angle of -70° * The angle dependence of (θ) has a negative peak in the specular reflection region (+70±10°). Furthermore, the graph shows a positive peak at angles outside the specular reflection region. It can also be interpreted that having a negative peak in the specular reflection region means that the angle (°) at the peak of that negative peak falls within the specular reflection region (70° in Figure 4). Similarly, having a positive peak at angles outside the specular reflection region means that the angle (°) at the peak of that positive peak falls within the range outside the specular reflection region (55° in Figure 4).

[0031] Furthermore, in this laminate, ΔL at an incident light angle of -70° * It is also preferable that the surface (outermost layer) has a lipophilic coating whose angle dependence of (θ) does not have a positive peak at angles other than the specular reflection region. * In the angle dependence of (θ), a positive peak can be observed only in the specular reflection region. By having such a lipophilic coated surface, ΔL due to fingerprint adhesion can be reduced. * (θ) can be reduced, making fingerprints less noticeable. Note that with a lipophilic coating, specular reflection increases, but by bringing the refractive index of the second predetermined layer closer to the refractive index of the fingerprint component, the visibility of fingerprints can be easily suppressed. When the outermost layer is lipophilic, its refractive index can be, for example, 1.30 to 1.50. Here, Figure 5 shows ΔL at a light incidence angle of -70° in a laminate having a lipophilic coating on its surface, after artificial fingerprint solution transfer and before wiping. * A graph showing an example of the angle dependence of (θ) is shown. In the graph shown in Figure 5, ΔL at an incident light angle of -70° * The angle dependence of (θ) does not have a positive peak at angles other than the specular reflection region (+70±10°), and has a positive peak only in the specular reflection region. Furthermore, the angle (°) at the position of the apex of this positive peak is within the range of the specular reflection region (70° in Figure 5). Furthermore, the wipeability of the surface of this laminate does not depend on the properties of the outermost layer (e.g., oil repellency or lipophilicity). Also, the aforementioned angle of change ΔL * The angle dependence of (θ) is not limited to the incident light angle of -70°; similar behavior is observed even at the incident light angle of -30°.

[0032] In the laminate having the above-described lipophilic coating, the distance from the surface of the outermost layer disposed on the second predetermined layer to the second predetermined layer is preferably 60 nm or less. If this distance is 60 nm or less, optical interference due to the difference between the refractive index of the lipophilic outermost layer and the refractive index of fingerprints (sebum) adhering to its surface can be suppressed, making fingerprints less noticeable. When the lipophilic outermost layer is laminated directly on the second predetermined layer, it is preferable that the thickness of the outermost layer be 60 nm or less. Furthermore, when other layers are disposed between the outermost layer and the second predetermined layer, it is preferable that the total thickness of the outermost layer and the other layer be 60 nm or less. By doing so, the lipophilicity of the surface of the outermost layer can be maintained while reducing the optical influence due to its refractive index. In other words, this allows the fingerprints to be considered to be substantially directly attached to the second predetermined layer.

[0033] In this laminate, from the viewpoint of providing excellent fingerprint resistance after wiping, the Δluminance on the surface calculated from the above-mentioned formula (2) is 0.1 [cd / m²]. 2 It is preferable that it be less than or equal to the following:

[0034] The above-mentioned values ​​are based on simulation results by the inventors. The simulations were performed under various conditions in which the refractive index (including the refractive index of air) and thickness of each component of the laminate were appropriately changed, and the desired numerical range was determined based on the results. For example, in the simulation in which the distance from the surface of the outermost layer, which is placed on the second predetermined layer, to the second predetermined layer was determined to be 60 nm or less in this laminate having a lipophilic coating, only the thickness of the lipophilic outermost layer of the laminate was changed. Also, while the thickness of a fingerprint is usually 10 to several hundred nm in actual measurements, 50 nm was used as a representative value in this simulation. The optical interference ΔY in the simulation is given by ΔY = ∫ A -R B )dλ, where R A : Intensity reflectance on the surface of the laminate, R B : This is the intensity reflectance of a fingerprint attached to the surface of a laminate. Y is the lightness L. * Since it is proportional to ΔY, if ΔL is a small value, * (θ) is also a small value in a similar manner.

[0035] In the simulation, the intensity reflectance Rm is given by the following equation I.

[0036]

number

[0037] In equation I, ηa is the refractive index of air, ηs is the refractive index of the substrate, and m is a component of the characteristic matrix [M]. The characteristic matrix [M] is expressed by equation II below.

[0038]

number

[0039] In Equation II, n is the number of layers stacked on the substrate, j is the order of each layer stacked on the substrate from the outermost layer (topmost layer), η is the optical admittance, and φ is the optical path length. If a fingerprint is present on the surface of the laminate, the fingerprint is assumed to be the outermost layer of the laminate. Furthermore, η is expressed by Equation III below, and φ is expressed by Equation IV below.

[0040]

number

[0041]

number

[0042] In equations III and IV, N is the refractive index of each layer, and φ is the angle of incidence to each layer. Also, in equation IV, d is the thickness of each layer, and λ is the wavelength of light.

[0043] In this embodiment, the distance from the surface of the laminate to the second predetermined layer, and the refractive index of each layer, can be measured non-destructively using an ellipsometer. Alternatively, the laminate may be cut, and the cut surface may be observed or analyzed after ion milling or FIB (Focused Ion Beam) processing. For example, qualitative analysis may be performed using XPS (X-ray photoelectron spectroscopy) to identify elements and structures. The number of layers and film thickness may also be confirmed using an electron microscope. By comparing the measurement results from the ellipsometer with other observation or analysis results, it is possible to confirm the structure with higher accuracy.

[0044] <Method for manufacturing laminates> In the method for manufacturing a laminate of the present invention (hereinafter sometimes referred to as "this manufacturing method"), the above-mentioned ΔL is applied to the surface of the laminate. * The laminate is fabricated such that (θ) is 0.1 or less. The laminate obtained by this manufacturing method can have excellent fingerprint resistance, taking into account wipeability. In this manufacturing method, ΔL *The surface of the laminate can also be surface-treated so that (θ) is 0.1 or less. The surface treatment method is not particularly limited as long as the effects of the present invention can be obtained, and conventionally known methods can be used. For example, an AG (Anti-Glare) coating can be applied to the surface of the substrate. The AG coating diffuses reflected light by creating very fine irregularities on the surface of the substrate, thereby suppressing reflection and glare.

[0045] The laminate of the present invention can be manufactured, for example, by the following procedure. First, a coating solution containing an active energy ray-curable resin is applied to a substrate such as a resin substrate or a glass substrate using a bar coater or the like, and dried by heating as needed (for example, 80°C for 90 seconds). Then, active energy ray curing is performed in an inert gas atmosphere (for example, nitrogen gas) to form a hard coat film of a predetermined thickness (for example, 5 μm).

[0046] Active energy ray curable resins contain polymerizable compounds that undergo a curing reaction upon irradiation with active energy rays to form a cured product. Polymerizable compounds can include monofunctional monomers, polyfunctional monomers, oligomers, and polymers having vinyl or (meth)acryloyl groups.

[0047] Examples of monofunctional monomers include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cetyl (meth)acrylate, isovonyl (meth)acrylate, cyclohexyl (meth)acrylate, tricyclodecyl (meth)acrylate, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and pentamethylpropyl (meth)acrylate. Peridyl, ethyl hexahydrophthalate (meth)acrylate, ethyl 2-hydroxypropylphthalate (meth)acrylate, 2-hydroxybutyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and other (meth)acrylate esters, styrene, α-methylstyrene, p-methoxystyrene, m-methoxystyrene, di-t-butyl fumarate, di-n-butyl fumarate, diethyl fumarate, mono(di)methyl itaconate, mono(di)ethyl itaconate, N-isopropylacrylamide, N-vinyl-2-pyrrolidone, etc. can be used.

[0048] Examples of polyfunctional monomers include polyfunctional polymerizable compounds containing two or more (meth)acryloyl groups, such as esters of polyhydric alcohols and (meth)acrylic acid, and urethane-modified acrylates. Examples of polyhydric alcohols include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, 2,2'-thiodiethanol, and 1,4-cyclohexanedimethanol; and trihydric or higher alcohols such as trimethylolpropane, glycerol, pentaerythritol, diglycerol, dipentaerythritol, and ditrimethylolpropane.

[0049] Urethane-modified acrylates can be obtained by a urethane reaction between an organic isocyanate having multiple isocyanate groups in one molecule and a (meth)acrylic acid derivative having hydroxyl groups. Examples of organic isocyanates having multiple isocyanate groups in one molecule include hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, xyleline diisocyanate, and dicyclohexylmethane diisocyanate, which have two isocyanate groups in one molecule, as well as organic isocyanates having three isocyanate groups in one molecule obtained by isocyanurate modification, adduct modification, or biuret modification of these organic isocyanates.

[0050] Examples of oligomers having vinyl groups or (meth)acryloyl groups include polyester oligomers, epoxy oligomers, urethane oligomers, polyether oligomers, alkyd oligomers, polybutadiene oligomers, polythiol polyene oligomers, and spiroacetal oligomers, as well as oligomers obtained by adding vinyl groups or (meth)acryloyl groups to oligomers made from polyhydric alcohol polyfunctional (meth)acrylic acid esters. Examples of polymers having vinyl groups or (meth)acryloyl groups include polymer types of the above-mentioned oligomers having vinyl groups or (meth)acryloyl groups.

[0051] Furthermore, the coating solution may contain additives as needed, such as diluent solvents, beads, fillers, photodegradable or thermally degradable polymerization initiators, metal oxides, surfactants, UV absorbers, infrared absorbers, antioxidants, photosensitizers, light stabilizers, and silane coupling agents.

[0052] Examples of diluent solvents include toluene, xylene, ethyl acetate, propyl acetate, butyl acetate, methyl cellsolve, ethyl cellsolve, ethyl cellsolve acetate, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, hexane, heptane, octane, decane, dodecane, propylene glycol monomethyl ether, and 3-methoxybutanol.

[0053] Examples of polymerization initiators include benzophenones, acetophenones, α-amyloxime esters, Michler-benzoylbenzoate, tetramethyl thurum monosulfide, and thioxanthones. Specifically, these include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-molpherinopropan-1-one, and 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl Examples include 1-propan-1-one, benzoin, 2,2-dimethoxy-1,2-diphenylethane-1-one, benzophenone, [4-(methylphenylthio)phenyl]phenylmethanone, 4-hydroxybenzophenone, 4-phenylbenzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, α-amyloxime ester, Michler-benzoylbenzoate, and tetramethylthurum monosulfide.

[0054] Examples of metal oxides include silica, hollow silica, aluminum oxide (alumina), titanium oxide, antimony oxide, zinc oxide, tin oxide, and zirconium oxide.

[0055] Surfactants are used for purposes such as compatibilization when various raw materials are blended, and for improving the smoothness of the coating. While not particularly limited, examples include acrylic copolymers (ionic and nonionic), methacrylic copolymers, leveling agents for solvent-based paints, and polysiloxane compounds.

[0056] As the photosensitizer, known compounds for polymerization initiators can be used, such as tertiary amines like tributylamine, triethylamine, polyethyleneimine, poly-n-butylphosphone, ethyl p-dimethylaminobenzoate, and isoamyl p-dimethylaminobenzoate.

[0057] The proportions of these various components can be set as appropriate within the range in which the effects of the present invention can be obtained, and are not particularly limited. By appropriately blending these various components, various properties such as the optical properties, coating properties, and durability of the manufactured laminate can be adjusted. Furthermore, the active energy rays and their irradiation dose can be set according to conventionally known conditions; for example, a metal halide lamp can be used.

[0058] Next, the obtained hard coat film is subjected to plasma treatment, and an AR (Anti-Reflection) coating film, which will be the first predetermined layer (high refractive index layer) and the second predetermined layer (low refractive index layer), is formed by vacuum deposition. Here, the constituent materials of each layer can be appropriately selected according to the desired refractive index and reflectance, and the number of layers and thickness can also be set as appropriate. For example, the first predetermined layer and the second predetermined layer may be formed as single layers each, or they may be laminates in which multiple layers are stacked alternately. Furthermore, the thickness of the first predetermined layer and the second predetermined layer can be, for example, 1 nm to 200 nm each. Furthermore, each layer may be formed using methods such as sputtering or wet coating.

[0059] The first predetermined layer can be made of materials such as niobium pentoxide (Nb2O5), titanium dioxide (TiO2), tungsten oxide (WO3), cerium oxide (CeO2), tantalum pentoxide (Ta2O5), zinc oxide (ZnO), indium oxide (In2O3), tin oxide (SnO2), hafnium oxide (HfO2), indium tin oxide (ITO), zirconium oxide (ZrO2), aluminum oxide (Al2O3), antimony oxide (Sb2O3), neodymium oxide (Nd2O3), or zinc sulfide (ZnS). Furthermore, if conductive properties are to be imparted to the first predetermined layer, for example, ITO or indium zinc oxide (IZO) can be used. Furthermore, the first predetermined layer may also be made of thermosetting resins such as phenolic resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, amino alkyd resin, melamine-urea cocondensation resin, silicon resin, or polysiloxane resin. In this case, the first predetermined layer may also contain inorganic materials such as silica, alumina, zirconia, or titania, or organic materials such as acrylic resin.

[0060] The second predetermined layer preferably contains an oxide of Si, and is preferably a layer mainly composed of SiO2 (an oxide of Si). Here, the main component refers to the component that is present in the largest quantity among the components contained in the target (in this case, the second predetermined layer). In addition to SiO2, the second predetermined layer may contain elements such as Na for the purpose of improving durability, Zr, Al, and N for the purpose of improving hardness, and Zr and Al for the purpose of improving alkali resistance. The second predetermined layer may contain, for example, magnesium fluoride (MgF2), sodium fluoride (NaF), cryolite (Na3AlF6), thiolite (Na5Al3F 14 It can also contain lithium fluoride (LiF), aluminum fluoride (AlF3), calcium fluoride (CaF2), styrene fluoride (SrF2), zirconium fluoride (ZrF4), barium fluoride (BaF2), yttrium fluoride (YF3), etc.

[0061] More specifically, for example, as a first predetermined layer, an AR coating film with a refractive index of 1.70 (e.g., film thickness: 150 nm) can be formed by vacuum deposition using raw materials: ZrO2 / Al2O3. Furthermore, for example, as a second predetermined layer, an AR coating film with a refractive index of 1.46 (e.g., film thickness: 90 nm) can be formed on the first predetermined layer by vacuum deposition using raw materials: SiO2.

[0062] Next, a silane coupling agent (e.g., a perfluoropolyether-based silane coupling agent) is applied to the second predetermined layer by spraying, and cured for a predetermined time (e.g., 12 hours) in a high-temperature, high-humidity environment (e.g., 50°C, 90% relative humidity) to form an AF (Anti-Fingerprint) coating film of a predetermined thickness (e.g., 10 nm) as the outermost layer. Based on the above, the laminate of the present invention can be obtained.

[0063] Furthermore, as the outermost layer, an oil-repellent coating layer can be used, formed using a fluorine compound having at least one functional group selected from the group consisting of fluoroalkyl groups, fluorooxyalkyl groups, fluoroalkenyl groups, fluoroalkanediyl groups, and fluorooxyalkanediyl groups. These functional groups may have some -H groups remaining, or all H groups may be replaced with fluorine (-F) groups. The structure may also be branched, and multiple branched structures may be linked together to form dimers, trimers, oligomers, or polymer structures. In addition, the fluorine compound may have reactive groups such as silyl ether groups, alkoxysilyl groups, silanol groups obtained by hydrolysis of alkoxysilyl groups, carboxyl groups, hydroxyl groups, epoxy groups, vinyl groups, allyl groups, acryloyl groups, and methacryloyl groups.

[0064] As the fluorine compound mentioned above, for example, a compound represented by the following general formula (A) can be used. R f1 -R 2 -D 1 ...General formula (A) (R f1R includes a moiety containing a fluoroalkyl group, a fluorooxyalkyl group, a fluoroalkenyl group, a fluoroalkanediyl group, or a fluorooxyalkanediyl group. 2 D 1 (This indicates the reactive site.)

[0065] Examples of compounds represented by general formula (A) include the following: 2,2,2-trifluoroethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2-perfluorobutyl ethyl acrylate, 3-perfluorobutyl-2-hydroxypropyl acrylate, 2-perfluorohexyl ethyl acrylate, 3-perfluorohexyl-2-hydroxypropyl acrylate, 2-perfluorooctyl ethyl acrylate, 3-perfluorooctyl-2-hydroxypropyl acrylate, 2-perfluorodecyl ethyl acrylate, 2-perfluoro-3-methylbutyl ethyl acrylate, 3- Perfluoro-3-methoxybutyl-2-hydroxypropyl acrylate, 2-perfluoro-5-methylhexylethyl acrylate, 3-perfluoro-5-methylhexyl-2-hydroxypropyl acrylate, 2-perfluoro-7-methyloctyl-2-hydroxypropyl acrylate, tetrafluoropropyl acrylate, octafluoropentyl acrylate, dodecafluoroheptyl acrylate, hexadecafluorononyl acrylate, hexafluorobutyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3,3-Pentafluoropropyl methacrylate, 2-Perfluorobutyl ethyl methacrylate, 3-Perfluorobutyl-2-hydroxypropyl methacrylate, 2-Perfluorooctyl ethyl methacrylate, 3-Perfluorooctyl-2-hydroxypropyl methacrylate, 2-Perfluorodecyl ethyl methacrylate, 2-Perfluoro-3-methylbutyl ethyl methacrylate, 3-Perfluoro-3-methylbutyl-2-hydroxypropyl methacrylate, 2-Perfluoro-5-methylhexyl ethyl methacrylate, 3-Perfluoro-5-methylhexyl Examples include 2-hydroxypropyl methacrylate, 2-perfluoro-7-methyloctylethyl methacrylate, 3-perfluoro-7-methyloctylethyl methacrylate, tetrafluoropropyl methacrylate, octafluoropentyl methacrylate, octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, hexadecafluorononyl methacrylate, 1-trifluoromethyltrifluoroethyl methacrylate, hexafluorobutyl methacrylate, and triacryloyl-heptadecafluorononenyl-pentaerythritol. In addition to these, a conventionally known oil-repellent coating layer can be used as the outermost layer.

[0066] Furthermore, as the outermost layer, for example, a lipophilic coating layer using a hydrolyzable organosilane compound (e.g., one containing a hindered ester group) or a hydrolysis condensate thereof can be used. The organosilane compound may contain a hindered ester group that has excellent lipophilicity and heat resistance, and a hydrolyzable silyl group (e.g., an alkoxysilyl group) or a hydroxyl group-containing silyl group. Conventionally known lipophilic coating layers can be used, but for example, the organosilane compound described in Japanese Patent Application Publication No. 2020-203838 can be used.

[0067] <Display device> The display device of the present invention (hereinafter sometimes referred to as "this display device") is not particularly limited as long as it comprises the laminate, and conventionally known laminates can be appropriately applied. Because this display device having the laminate has excellent fingerprint resistance, it can be suitably used in various electronic devices such as display devices equipped with touch panels, display panels, etc. [Examples]

[0068] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. Examples 1 to 15 described below are examples for evaluating the fingerprint resistance evaluation method of the present invention, and Examples 16 to 30 are examples for evaluating conventional evaluation methods.

[0069] (ΔL * (Confirmation of the correlation between the (θ) value and the sensory evaluation results) (1) Preparation of measurement samples First, a transfer foil of artificial fingerprint solution was prepared by dropping 2.0 g of artificial fingerprint solution onto a colorless, transparent polycarbonate plate measuring 115 mm x 90 mm and 2.0 mm thick, and then spin-coating it to achieve a HAZE value of 7 ± 2%. The HAZE value was measured using a haze meter (product name: NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.) and calculated using the formula: HAZE value (%) = diffuse transmittance ÷ total light transmittance. The artificial fingerprint solution used was solid at 20°C and dispersed at 40°C. Next, a natural rubber pad (natural rubber, rubber hardness: Shore E70) with a diameter of 20 mm and a thickness of 2 mm was pressed onto the transfer foil of the artificial fingerprint solution with a force of 60 N for 2 seconds. Then, the natural rubber pad with the artificial fingerprint solution transferred onto it was pressed onto the sample with a force of 60 N for 2 seconds to transfer the artificial fingerprint solution to the sample, thereby preparing a sample for measurement. In this embodiment, ΔL *Since the purpose is to verify the correlation between (θ) and the sensory evaluation results, a detailed explanation of each sample will be omitted, but for example, the following samples were used in the examples below. Example 1: A glass substrate with an AG coating on its surface, on which a first layer with a refractive index of 2.33 and a second layer with a refractive index of 1.46 were formed, and an oil-repellent coating was applied to the surface (reflectance: 0.3%). Example 2 and Example 3 (Example 3 and Example 17 are the same sample): The glass substrate of Example 1 was changed to a film substrate and a resin plate, respectively (both reflectance: 0.3%). Example 4 (same sample as Example 16): A resin plate with an AG coating on its surface was used as the substrate, and an oil-lipophilic coating was applied to the surface (reflectance: 4.5%). Example 5: A resin plate with an AG coating on its surface, on which a first layer with a refractive index of 2.33 and a second layer with a refractive index of 1.46 were formed (reflectance: 0.4%).

[0070] (2) Diffuse reflection fingerprint resistance ΔL * Measurement of (θ) In the obtained measurement samples, the areas where the artificial fingerprint solution was applied and then wiped, and the areas where it was not applied, i.e., the areas where the artificial fingerprint solution was applied and then wiped, and the areas where it was not applied, were measured using a variable angle colorimeter (product name: VC-2, manufactured by Suga Test Instruments Co., Ltd.) to measure CIE1976L * a * b * Angle of change in brightness L as defined by the display system * The values ​​were measured separately. Then, according to the following equation (1), the difference between the two measured values ​​ΔL * (θ) was calculated. Formula (1) ΔL * (θ) = L of the area wiped after artificial fingerprint transfer * -L of the non-transferable area of ​​the artificial fingerprint solution * However, the angle of incidence of light was set to -70° relative to the normal to the surface of the measurement sample, and the measurement angle was set to -5° relative to the normal to the surface of the measurement sample. Furthermore, Scotch-Brite No. 5000 (product name, manufactured by 3M Japan) was used as the wiping material, and the area to which the artificial fingerprint solution was applied was wiped by passing the Scotch-Brite No. 5000 (product name, manufactured by 3M Japan) over a 40mm x 70mm area with a load of 500g.

[0071] (3) Conducting sensory evaluation For the obtained measurement samples, an evaluation environment was constructed that reproduced the angle of incidence of sunlight in an actual vehicle environment and the positional relationship between the display device and the user. Sensory evaluation was then performed by humans based on the following sensory evaluation criteria. Specifically, artificial sunlight lighting was used as the sunlight, with an illuminance of 30,000 to 60,000 lux, an incidence angle of artificial sunlight lighting of -70°, and an observation angle by the user of -5°. • Sensory evaluation criteria 3: It was wiped off. 2: Some residue remains after wiping. 1: It cannot be wiped off.

[0072] Following the procedure described above, ΔL was applied to 15 measurement samples 1-15. * (θ) value measurement and user sensory evaluation are performed, ΔL * The correlation between the (θ) value and the sensory evaluation results was examined. Table 1 below shows the results for each measurement sample, and Figure 2 shows a graph illustrating the correlation between each measurement sample. [Table 1]

[0073] As shown in Figure 2, ΔL * A certain correlation was found between the (θ) value and the sensory evaluation results. Furthermore, ΔL * When (θ) is 0.1 or less, the sensory evaluation result is 3, indicating that it has excellent fingerprint resistance after wiping.

[0074] (Confirmation of the correlation between conventional fingerprint resistance evaluation methods and sensory evaluation results) (1) Preparation of measurement samples Eight pieces of gauze were laid, and a drop of oleic acid was dripped and left for 10 seconds. Then, silicon rubber was placed on the part where oleic acid was dripped, a load of 500 g was applied, and it was left stationary for 2 seconds. And the said silicon rubber was placed on new eight pieces of gauze, a load of 500 g was applied, and it was left stationary for 2 seconds. Subsequently, the said silicon rubber was transferred onto the sample, a load of 500 g was applied and left stationary for 2 seconds to transfer oleic acid to the sample, and a measurement sample was prepared.

[0075] (2) ΔL * (Measurement of SCI) In the obtained measurement sample, for the site where oleic acid was transferred and the site where it was not transferred, that is, the site where oleic acid adhered and the site where it did not adhere, using a color difference meter (product name: CM-5, manufactured by Konica Minolta), CIE1976L * a * b * the lightness L defined by the display system * was measured respectively. And according to the following formula (3), the difference ΔL * (SCI) between the two measured values was calculated. Formula (3) ΔL * (SCI) = L of the oleic acid transfer part * - L of the non-oleic acid transfer part *

[0076] (3) Conducting sensory evaluation Using the above-mentioned sensory evaluation method, a sensory evaluation by humans was conducted on the obtained measurement sample. According to the above procedure, for 15 measurement samples 16 to 30, the measurement of the ΔL * (SCI) value and the sensory evaluation by users were carried out, and the correlation between the ΔL * (SCI) value and the sensory evaluation result was confirmed. The following were adopted as the sensory evaluation criteria. · Sensory evaluation criteria 5: Fingerprint marks are not visible. 4: Fingerprint marks are hardly visible. 3: Fingerprint marks are slightly visible. 2: Fingerprint marks are visible. 1: Fingerprint marks are clearly visible.

[0077] Subsequently, the results of each measurement sample are shown in Table 2 below, and a graph showing the correlation of each measurement sample is described in FIG. 3. Note that ΔL * (SCI) is not the value after wiping, but it can be seen from FIG. 3 that the conventional evaluation method cannot obtain results reflecting the actual sensory evaluation in the vehicle environment.

Table 2

[0078] As described above, the optical index ΔL showing the reflection intensity of the total angle integrated by the integrating sphere, which has been conventionally used as an evaluation index for fingerprint resistance * (SCI) was found to be difficult to properly evaluate fingerprint resistance regardless of wiping. Also, in the conventional transfer method described above, there were cases where oleic acid remained on the gauze or droplet repellency occurred, and there were cases where oleic acid could not be transferred to the sample with good reproducibility.

[0079] (Measurement of squalene adhesion amount) Assuming a laminate with fingerprints attached, after transferring artificial fingerprint liquid to the surface of the measurement sample and before the wiping operation, normal hexane was impregnated into quartz wool from which the attached oil was removed by solvent washing for the artificial fingerprint liquid adhering to the surface of the measurement sample, and the surface was rubbed and washed, and then washed away with normal hexane, and the washing liquid was collected in a 40 mL container. Then, after putting the used quartz wool into the container, it was sealed, and a solution subjected to ultrasonic extraction for 5 minutes was measured in a 50 mL volume and used for a measuring device to measure the squalene amount. The calibration curve used for measuring the squalene amount was created from the area values obtained from the adjusted concentration and the measurement results by subjecting a standard solution diluted stepwise with normal hexane to the measuring device. Note that the squalene content in the used artificial fingerprint liquid was 13% by mass. · Measuring device Gas chromatography (GC): Agilent Technologies 7890B (trade name) Mass spectrometer (MS): JEOL JMS-Q1500GC (product name) ·GC conditions Inlet temperature: 280℃ Introduction method: splitless method Volume introduced: 2 μL (using an autosampler) Analytical column: Agilent Technologies (product name) 5% Phenyl-95% Methylsiloxane Carrier gas: Helium Head pressure: 64.50 kPa (constant pressure) Oven conditions: 60°C (3 min) - 20°C / min - 300°C MS conditions Ionization method: EI Measurement method: Scan measurement using electron ionization method Measurement mass range: m / Z = 40~425 Ionization voltage: 70 eV Ion source temperature: 200℃ Interface temperature: 250℃

[0080] As the measurement sample mentioned above, a display device equipped with an oil-repellent coating, specifically, ΔL at a light incidence angle of -70° * We used a (θ) whose angle dependence has a negative peak in the specular reflection region (70±10°) and a positive peak at angles outside the specular reflection region. * The angular dependence of (θ) is the diffuse reflection fingerprint resistance ΔL mentioned above. * In the same method as for measuring (θ), the measurement angle is set to -60° to +85°, and ΔL for each angle is measured. * This was determined by calculating (θ). Below are the amount of squalene attached to the measurement sample after artificial fingerprint solution transfer and before wiping (assuming fingerprints were attached), and ΔL after artificial fingerprint solution transfer and wiping. * The relationship with (θ) is shown in Table 3 below. [Table 3]

[0081] As shown in Table 3 above, in a display device equipped with an oil-repellent coating, if the amount of squalene adhering to the surface after artificial fingerprint solution transfer (assuming fingerprints have been applied) is less than 40 μg, the ΔL after wiping is * (θ) is less than 0.1, indicating excellent fingerprint resistance. Note that ΔL at an incident light angle of -70° * In a display device equipped with an oleophilic coating where the angle dependence of (θ) does not have a positive peak outside the specular reflection region, fingerprint components adhere to the oleophilic surface and blend in, so ΔL * (θ) is not affected by the amount of squalene attached and has excellent fingerprint resistance (for example, even when the amount of squalene attached exceeds 100 μg, ΔL * (θ is -0.09).

[0082] From the above, it can be seen that the fingerprint resistance evaluation method of the present invention is an excellent evaluation method that can also be applied to in-vehicle display devices. It should be noted that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0083] 1 light source 2. Light-transmitting objects 3 Display device N normal

Claims

1. The difference in measurement value ΔL between a portion where the artificial fingerprint liquid has been transferred and then wiped off and a portion where the artificial fingerprint liquid has not been transferred is calculated using a goniochromatic colorimeter using the following formula (1): ＊ A laminate having a surface in which (θ) is 0.1 or less: Formula (1) ΔL ＊ (θ) = L of the wiped area after transfer of the artificial fingerprint liquid ＊ - L of the part where the artificial fingerprint liquid is not transferred ＊ However, the light incident angle is set to −70° with respect to the normal to the surface of the object to be measured, and the measurement angle is set to −5° with respect to the normal to the surface of the object to be measured.

2. a substrate, a predetermined layer disposed on the substrate, and an outermost layer disposed on the predetermined layer; the predetermined layer includes a first predetermined layer on the substrate side and a second predetermined layer on the outermost layer side, The laminate according to claim 1 , wherein the refractive index of the first predetermined layer is 2.00 or less.

3. a substrate, a predetermined layer disposed on the substrate, and an outermost layer disposed on the predetermined layer; the predetermined layer includes a first predetermined layer on the substrate side and a second predetermined layer on the outermost layer side, The laminate according to claim 1 , wherein the refractive index of the second predetermined layer is 1.43 or more and 1.49 or less.

4. On the surface of the laminate, ΔL at the light incident angle of −70° ＊ The angular dependence of (θ) has a negative peak in the specular reflection region and a positive peak at angles other than the specular reflection region, 2. The laminate according to claim 1, wherein the amount of squalene attached to the surface of the laminate after the artificial fingerprint liquid has been transferred and before the liquid is wiped off is less than 40 μg.

5. On the surface of the laminate, ΔL at the light incident angle of −70° ＊ 2. The laminate according to claim 1, wherein the angular dependence of (θ) does not have a positive peak at an angle other than the specular reflection region.

6. The laminate according to claim 5 , wherein the outermost layer is disposed on the second predetermined layer, and the distance from the surface of the outermost layer to the second predetermined layer is 60 nm or less.

7. 2. The laminate according to claim 1, wherein the method for transferring the artificial fingerprint liquid comprises attaching the artificial fingerprint liquid to a transfer substrate by a spin coating method, preparing a transfer foil having a haze value of 7±2%, pressing a false finger against the transfer foil with a load of 60 N, and then pressing the false finger against the surface of the laminate with a load of 60 N for 2 seconds.

8. A display device comprising the laminate according to any one of claims 1 to 7.

9. The difference in measurement value ΔL between a portion of the surface of the laminate where the artificial fingerprint liquid has been transferred and then wiped off and a portion where the artificial fingerprint liquid has not been transferred is calculated using a goniochromatometer according to the following formula (1): ＊ A method for producing a laminate, comprising producing the laminate so that (θ) is 0.1 or less: Formula (1) ΔL ＊ (θ) = L of the wiped area after transfer of the artificial fingerprint liquid ＊ - L of the part where the artificial fingerprint liquid is not transferred ＊ However, the light incident angle is set to −70° with respect to the normal to the surface of the object to be measured, and the measurement angle is set to −5° with respect to the normal to the surface of the object to be measured.

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