Cover panel, decorative sheet, and display device

Abstract

[Problem] To improve visibility of the display screen, the cover panel or the decorative sheet of a display device in a place where a pattern layer, a transparent or translucent mat layer and a transparent or translucent glossy layer overlap. [Solution] The pattern layer 22 has a pattern colored with an interference pigment 22p which develops color by interference of the reflected light of second visible light entering a surface exposure region EX from the outside. The glossy layer 24 is located on a layer surface 23s of the mat layer 23. The glossy layer 24 is a layer for forming a protrusion 24p and a recess 24r in the surface exposure region EX and increasing the surface roughness of the surface exposure region EX as compared with the case where the glossy layer 24 is absent, and constituted so that the Haze value of the surface exposure region EX is 40% to 85% inclusive.

Description

Cover panel, decorative sheet and display device

[0001] The present invention relates to a cover panel having an interference pigment, a decorative sheet having an interference pigment, and a display device having an interference pigment.

[0002] Conventional display devices use a pattern layer having a pattern colored with an interference pigment, as described in, for example, Patent Document 1 (Japanese Patent No. 6839319) and Patent Document 2 (Japanese Patent No. 5725581). The pattern colored with the interference pigment is difficult to see with transmitted light but easily visible with reflected light. In such display devices, when visible light emitted from the display screen passes through the pattern colored with the interference pigment, the display on the display screen is visible without being obstructed by the pattern. Naturally, when no visible light is emitted from the display screen of the display device, the pattern colored with the interference pigment is visible solely by visible light incident on the pattern layer from outside the display device. It is conceivable to apply a gloss layer and a matte layer, as described in, for example, Patent Document 3 (Japanese Patent Laid-Open No. 2000-62081), to such display devices to impart a desired tactile feel to the exposed surface area of ​​the display screen on which the image is projected.

[0003] Japanese Patent No. 6839319 Japanese Patent No. 5725581 Japanese Patent Laid-Open No. 2000-62081

[0004] However, when a pattern (pattern layer) colored with an interference pigment, a gloss layer (shiny layer), and a matte layer are superimposed, the display screen becomes difficult to see compared to when there is no pattern (pattern layer) colored with an interference pigment. The reason why the display screen becomes difficult to see and visibility decreases is thought to be due to the unevenness caused by the matte layer and gloss layer and the interference pigment in the pattern layer.

[0005] The object of the present invention is to improve the visibility of the display screen, cover panel, or decorative sheet of a display device at the location where a pattern layer having an interference pigment, a transparent or translucent matte layer, and a transparent or translucent glossy layer overlap.

[0006] Several aspects will be described below as means for solving the problems. These aspects can be combined as desired. A cover panel according to a first aspect of the present invention is provided for a display screen that radiates first visible light to visually display information or images, and is disposed in an exposed surface area of ​​the display device that transmits the first visible light radiated from the display screen. The cover panel includes a transparent or translucent base film, a pattern layer, a transparent or translucent matte layer, and a transparent or translucent gloss layer. The transparent or translucent base film has a first main surface onto which the first visible light radiated from the display screen is incident, and a second main surface from which the first visible light is emitted. The pattern layer is disposed on the first main surface side of the base film, and has a pattern colored with an interference pigment that develops color due to interference of reflected light of second visible light that is incident on the exposed surface area from the outside. The matte layer is disposed on the second main surface side of the base film, and is a layer for matting the exposed surface area. The gloss layer is disposed on the surface of the matte layer. The gloss layer is a layer for forming convex portions and concave portions in the exposed surface region to increase the surface roughness of the exposed surface region compared to a case where the gloss layer is not present, and is configured so that the haze value of the exposed surface region is 40% or more and 85% or less. According to the cover panel of the first aspect, by setting the haze value of the cover panel including the pattern layer colored with an interference pigment to 40% or more and 85% or less, the gloss layer can impart a tactile feel of the concave portions and convex portions to the exposed surface region, and can also make the boundaries between the convex portions and the concave portions less noticeable, improving the visibility of the cover panel.

[0007] A cover panel according to a second aspect is configured such that the recesses and protrusions of the cover panel according to the first aspect are made of a gloss layer having a wave-like shape in which recesses and protrusions are repeated. In the cover panel according to the second aspect, the gloss layer can provide a difference in haze value between the protrusions and recesses, making it possible to easily set the haze value of the cover panel to an appropriate value and facilitating improvement of visibility. In the cover panel according to a third aspect, the gloss layer of the cover panel according to the second aspect is configured such that the gradation of the recesses is 30% or more and 60% or less. In the cover panel according to the third aspect, the gradation of the recesses is 30% or more and 60% or less, making it easy to appropriately set the difference in haze value between the protrusions and recesses and facilitating improvement of visibility.

[0008] A cover panel according to a fourth embodiment is the cover panel according to the third embodiment, wherein the bottom surface of the recess is formed by the surface of a matte layer. In the cover panel according to the fourth embodiment, the haze value of the bottom surface of the recess can be set to the haze value of the matte layer, making it easier to set the haze value of the recess and to improve visibility. In the cover panel according to a fifth embodiment, in the cover panel according to the fourth embodiment, the region of the laminate consisting of the base film and the matte layer has a haze value of 65% or more and 80% or less. In the cover panel according to the fifth embodiment, by setting the haze value of the region of the laminate consisting of the base film and the matte layer to 65% or more and 80% or less, blurring of the display on the display screen can be suppressed and visibility can be significantly improved. The cover panel of the sixth aspect is the cover panel of the first to fifth aspects, in which the haze value of the cover panel is 60% or more and 70% or less, and therefore the visibility of the boundary between the concave and convex portions is suppressed while suppressing a decrease in the contrast of the display on the display screen, thereby significantly improving visibility.

[0009] A decorative sheet according to a seventh aspect is provided for a display screen that radiates first visible light to visually display information or images, and is disposed in an exposed surface region of a display device that transmits the first visible light radiated from the display screen. This decorative sheet includes a transparent or translucent base film, a pattern layer, a transparent or translucent matte layer, and a transparent or translucent gloss layer. The base film has a first main surface onto which the first visible light radiated from the display screen is incident and a second main surface from which the first visible light is emitted. The pattern layer is disposed on the first main surface side of the base film and has a pattern colored with an interference pigment that develops color due to interference of reflected light of second visible light that is incident on the exposed surface region from the outside. The matte layer is disposed on the second main surface side of the base film and serves to matte the exposed surface region. The gloss layer is disposed on the surface of the matte layer. The gloss layer is a layer for forming convex portions and concave portions in the exposed surface region to increase the surface roughness of the exposed surface region compared to a case where the gloss layer is not present, and is configured so that the haze value of the portion corresponding to the exposed surface region is 40% or more and 85% or less. In the decorative sheet according to the seventh aspect, by setting the haze value of the decorative sheet including the pattern layer colored with an interference pigment to 40% or more and 85% or less, the gloss layer can impart a tactile feel of the concave portions and convex portions to the exposed surface region, and the boundaries between the convex portions and the concave portions can be made less noticeable, improving the visibility of the decorative sheet.

[0010] A display device according to an eighth aspect includes a display screen that emits first visible light to visually display information or images, and a cover panel that is disposed on an exposed surface area of ​​the display screen and transmits the first visible light emitted from the display screen. The cover panel of this display device includes a transparent or translucent base film, a pattern layer, a transparent or translucent matte layer, and a transparent or translucent glossy layer. The base film has a first main surface onto which the first visible light emitted from the display screen is incident and a second main surface from which the first visible light is emitted. The pattern layer is disposed on the first main surface side of the base film and has a pattern colored with an interference pigment that develops color due to interference of reflected light of second visible light that is incident on the exposed surface area from the outside. The matte layer is disposed on the second main surface side of the base film and serves to matte the exposed surface area. The glossy layer is disposed on the surface of the matte layer. The gloss layer is a layer for forming convex portions and concave portions in the exposed surface region to increase the surface roughness of the exposed surface region compared to a case where the gloss layer is not present, and is configured so that the haze value of the exposed surface region of the cover panel is 40% or more and 85% or less. According to the display device of the eighth aspect, by setting the haze value of the cover panel including the pattern layer colored with an interference pigment to 40% or more and 85% or less, the gloss layer can impart a tactile feel of the concave portions and convex portions to the exposed surface region, and can also make the boundaries between the convex portions and the concave portions less noticeable, improving the visibility of the cover panel.

[0011] The cover panel, decorative sheet or display screen of the display device according to the present invention has improved visibility.

[0012] 1 is a plan view of a smartphone according to an embodiment; FIG. 2 is a schematic cross-sectional view showing an example of a cover panel according to the first embodiment; FIG. 3 is a diagram for explaining the relationship between the gradation of recesses and the haze value; FIG. 4 is a partial plan view showing a part of the design of the design layer; FIG. 5 is a partial plan view showing a part of an example of a pattern of the gloss layer; FIG. 6 is a partial plan view showing a part of a display screen of a smartphone; FIG. 7 is a schematic cross-sectional view showing an example of an interference pigment forming the design; FIG. 8 is a schematic cross-sectional view showing a change in appearance due to the interference pigment; FIG. 9 is a schematic cross-sectional view showing an example of a cover panel according to a second embodiment; FIG. 10 is a schematic cross-sectional view showing lamination of a decorative sheet according to one modified example; FIG. 11 is a schematic cross-sectional view showing a part of the configuration of a smartphone using a decorative sheet; FIG. 12 is a schematic cross-sectional view showing lamination of a decorative sheet according to another modified example; FIG. 13 is a schematic cross-sectional view showing a part of the configuration of a smartphone using a decorative sheet; FIG. 14 is a plan view for explaining air bubbles that may occur during lamination of a decorative sheet; FIG. 15 is a schematic cross-sectional view showing an example of a cover panel according to modified example C; FIG. 16 is a schematic cross-sectional view showing an example of a cover panel according to modified example D; FIG. 17 is a schematic cross-sectional view showing another example of the cover panel according to modified example D; and FIG. 18 is a process diagram showing a manufacturing process of a cover panel according to modified example E. 1 is a photograph, substituted for a drawing, showing an enlarged view of an icon on the display screen of a conventional smartphone having a geometric pattern formed on a gloss layer; FIG. 1 is a photograph, substituted for a drawing, showing an enlarged view of an icon on the display screen of a smartphone having a geometric pattern formed on a gloss layer according to the first embodiment; FIG. 2 is a photograph, substituted for a drawing, showing an enlarged view of an icon on the display screen of a smartphone having a geometric pattern formed on a gloss layer according to the second embodiment; FIG. 2 is a photograph, substituted for a drawing, showing an enlarged view of an icon on the display screen of a conventional smartphone having a wood grain pattern formed on a gloss layer; FIG. 3 is a photograph, substituted for a drawing, showing an enlarged view of an icon on the display screen of a smartphone having a wood grain pattern formed on a gloss layer according to the first embodiment; FIG. 3 is a photograph, substituted for a drawing, showing an enlarged view of an icon pattern of a conventional concealing layer having a wood grain pattern formed on a gloss layer; FIG. 4 is a photograph, substituted for a drawing, showing an enlarged view of an icon pattern of a concealing layer according to the first embodiment having a wood grain pattern formed on a gloss layer.10 is a photograph showing an enlarged icon pattern of a concealing layer according to a second embodiment in which a wood grain pattern is formed in a glossy layer;

[0013] First Embodiment (1) Overall Configuration FIG. 1 illustrates a smartphone 1 as an example of a display device according to a first embodiment of the present invention. Here, the smartphone 1 is used as an example of a display device. However, display devices to which the present invention is applicable are not limited to the smartphone 1. Examples of such display devices include display devices built into mobile computers, display devices for automobiles, and monitors for various devices. Examples of display devices for automobiles include monitors for automobile navigation systems and heat control panels. The smartphone 1 includes a display screen 10. Information or images are visually displayed on the display screen 10. Information displayed on the display screen 10 includes, for example, text information, information conveyed by symbols such as graphic symbols, and visualized information such as graphs. The images displayed on the display screen 10 may be still images or moving images. Examples of images displayed on the display screen 10 include photographs, illustrations, and maps. For example, an icon 11 displayed on the smartphone 1 is both information and an image. When the display screen 10 is displaying information, the display screen 10 becomes bright, and when the display screen 10 is not displaying information, the display screen 10 becomes dark. In other words, when display screen 10 is displaying, first visible light is emitted from display screen 10, and when display is not displaying, first visible light is not emitted from display screen 10. For example, if display screen 10 is a liquid crystal screen, the first visible light is light emitted from a backlight. For example, if display screen 10 is an organic EL screen, the first visible light is light emitted from the organic EL screen. Here, EL is an abbreviation for electroluminescence.

[0014] A cover panel 20 is provided for the display screen 10. Specifically, the display screen 10 is covered with the cover panel 20. The cover panel 20 is transparent or translucent. Therefore, the first visible light emitted from the display screen 10 passes through the cover panel 20. FIG. 2 shows an example of the configuration of the cover panel 20. The cover panel 20 includes a base film 21, a pattern layer 22, a matte layer 23, and a glossy layer 24. The base film 21 is transparent or translucent. The base film 21 has a first main surface 21a onto which the first visible light emitted from the display screen 10 is incident and a second main surface 21b from which the first visible light exits. In other words, the first visible light emitted from the display screen 10 enters the base film 21 through the first main surface 21a, passes through the base film 21, and exits through the second main surface 21b. In FIG. 2, the first visible light enters and exits in the direction indicated by an arrow AR1, and the second visible light enters and exits in the direction indicated by an arrow AR2.

[0015] The design layer 22 is disposed on the first main surface 21a of the base film 21. The design layer 22 is disposed, for example, on a transparent or translucent molded resin 19, which is one of the components of the display screen 10. The molded resin 19 is, for example, a resin substrate that constitutes the display screen 10. The resin used for the molded resin 19 is, for example, polymethyl methacrylate (PMMA) or polycarbonate (PC). A glass substrate may be used instead of the molded resin 19. The design layer 22 has, for example, a design colored with an interference pigment, or a design colored with an interference pigment and a metallic ink design. The binder resin for holding the interference pigment in the design layer 22 is transparent or translucent. The interference pigment in the design layer 22 develops its color due to interference of reflected light of second visible light incident on the cover panel 20 from outside the smartphone 1. Therefore, the interference pigment does not develop color in the first visible light transmitted through the design layer 22, or if it does, the color is extremely weak. Therefore, when a display is being displayed on the display screen 10 of the smartphone 1, the design of the design layer 22 does not substantially affect the display on the display screen 10. In other words, when a display is being displayed on the display screen 10 of the smartphone 1, the operator 100 of the smartphone 1 does not recognize the design of the design layer 22, but recognizes the design of the design layer 22 when the display screen 10 is not displaying. The design layer 22 having a metallic ink design reflects a relatively large amount of incident light incident from the surface of the metallic ink design and can transmit a portion of incident light incident from the back surface. The thickness of the metallic ink is, for example, 0.5 μm to 5 μm. The metallic ink is, for example, an ink in which metal powder is uniformly dispersed in a transparent binder resin. By providing a metallic ink pattern, more light is reflected on the surface of the cover panel 20 than when no metallic ink pattern is provided, making the pattern of the pattern layer 22 look brighter.

[0016] The matte layer 23 is disposed on the second main surface 21b of the substrate film 21. FIG. 2 shows an example in which the matte layer 23 is provided directly on the substrate film 21. However, the matte layer 23 does not have to be provided directly on the substrate film 21; another transparent or translucent layer may be provided between the matte layer 23 and the substrate film 21. The matte layer 23 is a layer for matting the cover panel 20. The matte layer 23 contributes to suppressing reflection of the second visible light in the cover panel 20 and uniformly diffusing the first visible light, thereby improving the visibility of the display screen 10. Therefore, the haze value of the region of the laminate in which the matte layer 23 is provided on the substrate film 21 is larger than the haze value of the substrate film 21 alone. The haze value is measured in accordance with the test method described in JIS-K7136. Because the cover panel 20 includes other components, such as the pattern layer 22 and the glossy layer 24, in addition to the base film 21 and the matte layer 23, it may be difficult to measure the haze value of the portion of the cover panel 20 consisting only of the base film 21 and the matte layer 23 using the test method described in JIS-K7136. Therefore, the concept of a laminate consisting of the base film 21 and the matte layer 23 is introduced. Such a laminate is, for example, a film in which the matte layer 23 is formed on the entire surface of a single base film 21. The haze value of the region of the laminate consisting of the base film 21 and the matte layer 23 is the haze value excluding all other components other than the base film 21 and the matte layer 23. In other words, the haze value of such a region of the laminate can be obtained, for example, by measuring the haze value of the material of the cover panel 20 in which only the matte layer 23 is formed on the base film 21. The glossy layer 24 is disposed on the layer surface 23s of the matte layer 23. The gloss layer 24 is a layer for forming the convex portions 24p and the concave portions 24r in the exposed surface area EX of the cover panel 20. The exposed surface area EX is the portion of the cover panel 20 of the smartphone 1 shown in FIG. 1 other than the edge 2. Here, the exposed surface area EX extends to the periphery of the display screen 10, but the exposed surface area EX may be limited to the display screen 10. Furthermore, the area in which the convex portions 24p and the concave portions 24r are formed may be limited to a portion of the display screen 10.The repeated formation of convex portions 24p and concave portions 24r in the surface-exposed region EX increases the surface roughness of the surface-exposed region EX. As a result, when an operator's finger touches the surface-exposed region EX, the finger feels the roughness of the surface-exposed region EX due to the gloss layer 24. If the gloss layer 24 were not formed in the surface-exposed region EX, the surface-exposed region EX of the cover panel 20 would be smoother than if the gloss layer 24 were formed. For example, in areas of the cover panel 20 that are not exposed, such as the edge 2 of the smartphone 1, there is no need to impart the desired feel, so the gloss layer 24 may not be provided, or the gloss layer 24 may be provided but the pattern formed by the convex portions 24p and concave portions 24r may not be formed. If the gloss layer 24 is provided but the pattern formed by the convex portions 24p and concave portions 24r is not formed, for example, the gloss layer 24 under the edge 2 may consist of only the convex portions 24p, only the concave portions 24r, or the matte layer 23.

[0017] The haze value of the cover panel 20 is set to 40% or more and 85% or less. However, to ensure good visibility, the haze value of the cover panel 20 is preferably set to 60% or more and 70% or less. When the haze value of the cover panel 20 is set within the above-mentioned range, the haze value of the region of the laminate consisting of two layers, the base film 21 and the matte layer 23, is set to 70% or more and 90% or less. The haze value of the region of the laminate consisting of three layers, the base film 21, the matte layer 23, and the glossy layer 24, is set to 40% or more and 65% or less. When the glossy layer 24 has this haze value, the entire surface is smooth and free of irregularities; in other words, the recesses 24r are not formed and the same state as the protrusions 24p is spread throughout. For example, if a sheet prepared as the material for the cover panel 20 includes a base film 21, a matte layer 23, and a glossy layer 24, the haze value of the region of the laminate consisting of the three layers of the base film 21, the matte layer 23, and the glossy layer 24 can be easily measured. The haze value of the glossy layer 24 formed to have only the recesses 24r is greater than that of the glossy layer formed to have only the protrusions 24p. In other words, as shown in FIG. 3 , if the glossy layer 24 is formed with a uniform thickness over the entire surface, the smaller the gradation of the recesses 24r, the greater the haze value. The haze value of the cover panel 20 is set to 40% or more and 85% or less, taking into account the influence of the pattern of the alternatingly arranged protrusions 24p and recesses 24r. Here, the gradation of the recesses 24r will be described. For example, a large number of dots D1 are printed in the recesses 24r. When a portion of the recess 24r is extracted and enlarged in a plan view, the numerous dots D1 may be separated from one another or may be in contact with one another depending on the type of printing plate used to print the recess 24r and the protrusion 24p. In this specification, a gradation of 100% is defined as a case where all dots D1 are stuck together and the amount of resin per unit volume is the same as that of the protrusion 24p, a gradation of 0% is defined as a case where no dots D1 are present, and a gradation of 50% is defined as a density of dots D1 where the amount of resin per unit volume is half that of the protrusion 24p.If the convex portions 24p are printed using the same method as the concave portions 24r, the gradation of the dots D1 in the concave portions 24r reaching 100% means that the entire surface is printed with the same maximum density of dots D1, resulting in a flush surface and making the convex portions 24p and the concave portions 24r indistinguishable. For example, if the gloss layer 24 is formed by printing and dots of the same shape are used for the concave portions 24r and the convex portions 24p, the convex portions 24p can be printed with the maximum dot density and the concave portions 24r with a lower dot density than the convex portions 24p, thereby forming a surface on the cover panel 20 that gives the impression of alternating convex portions 24p and concave portions 24r. As long as the amount of resin per unit area can be changed between the convex portions 24p and the concave portions 24r, the convex portions 24p and the concave portions 24r may be formed by methods other than dot printing. For example, the concave portions 24r and the convex portions 24p may be formed by pressing a textured plate against the surface. The haze value of the cover panel 20 is preferably set to 50% or more and 85% or less to obtain even better visibility. When the haze value of the cover panel 20 is set within the aforementioned range, the haze value of the region of the laminate consisting of two layers, the base film 21 and the matte layer 23, is set to 80% or more and 90% or less. The haze value of the region of the laminate consisting of three layers, the base film 21, the matte layer 23, and the glossy layer 24, is set to 50% or more and 65% or less. When the glossy layer 24 forms irregularities in the surface-exposed region EX, if the difference in haze value between the convex portions 24p and the concave portions 4r of the glossy layer 24 is too large, visibility is reduced. However, if the haze value of the cover panel 20 is too low, the contrast of the irregular pattern is lost, reducing the design. The haze value range of the cover panel 20, 40% or more and 85% or less, is a range that achieves both design and visibility. The difference in haze value between the region of the laminate consisting only of the base film 21, the matte layer 23, and the glossy layer 24 and the region of the laminate consisting only of the base film 21 and the matte layer 23 is preferably set to 20% or more and 40% or less. The haze value of the region of the laminate consisting only of the base film 21 and the matte layer 23 can be obtained, for example, by measuring the haze value of a film in which the matte layer 23 is formed on the base film 21 as a material for producing the cover panel 20.The haze value of the region of the laminate consisting of only the base film 21, the matte layer 23, and the glossy layer 24 can be obtained, for example, by measuring the haze value of a film in which the matte layer 23 and the glossy layer 24 are formed on the base film 21 used as a material for producing the cover panel 20. The region in which only the matte layer 23 and the glossy layer 24 are formed on the base film 21 used as a material for producing the cover panel 20 and the region in which only the matte layer 23 is formed on the base film 21 may each have a continuous portion over a large area. In such a case, if the haze value of each large area can be measured using the film, the haze values ​​of the region in the laminate consisting of only the matte layer 23 and the glossy layer 24 on the base film 21 and the region in which only the matte layer 23 is formed on the base film 21 may be measured directly using the cover panel 20. It is more preferable that the difference in haze value between the region in the laminate consisting of only the base film 21, the matte layer 23, and the glossy layer 24 and the region in the laminate consisting of only the base film 21 and the matte layer 23 be set to 20% or more and 30% or less.

[0018] The haze value varies depending on the location in the exposed surface region EX due to the pattern formed by the recesses 24r and protrusions 24p of the gloss layer 24. When the minimum area measurable by a haze value measuring device is smaller than the area of ​​the exposed surface region EX, if the measured haze value of any location in the exposed surface region EX satisfies the condition of 40% or more and 85% or less, it can be determined that the visibility of the location that satisfies this condition is improved.

[0019] (2) Structure of Each Part of the Cover Panel 20 (2-1) Substrate Film 21 The substrate film 21 is, for example, a transparent or translucent resin film, a transparent or translucent elastomer film, or transparent or translucent glass. Examples of resin films constituting the substrate film 21 include thermoplastic resin films made of a single resin, thermoplastic resin films made of a mixture of multiple resins, and films made of multiple layers of thermoplastic resin films. Examples of resin films include resin films made of polyester resin, polyethylene terephthalate (PET) resin, acrylic resin, polycarbonate resin, polybutylene terephthalate (PBT) resin, triacetyl cellulose resin, styrene resin, or ABS resin, multilayer films of acrylic resin and ABS resin, and multilayer films of acrylic resin and polycarbonate resin. The thickness of the substrate film 21 is selected, for example, from a range of 10 μm to 1000 μm.

[0020] (2-2) Design Layer 22 The design of the design layer 22 is, for example, a geometric pattern as shown in FIG. 4 . The design layer 22 includes a design (here, a geometric pattern) that is visible when the display screen 10 is off. The geometric pattern shown in FIG. 4 is a grayscale pattern in which multiple areas separated by straight lines are expressed in different gradations. While FIG. 4 shows a geometric pattern as the design of the design layer 22, the design is not limited to geometric patterns and may be a natural pattern, such as a wood grain pattern, that imitates the shapes or patterns of plants, animals, terrain, etc. that exist in nature. The thickness of the design layer 22 is selected, for example, from a range of 1 μm to 50 μm. The design layer 22 is formed on the base film 21 by, for example, screen printing, offset printing, flexographic printing, gravure printing, or digital printing using inkjet or toner. The binder of the design layer 22 is made of, for example, one or more of vinyl chloride-vinyl acetate copolymer resin, acrylic resin, thermoplastic urethane resin, and polyester resin.

[0021] FIG. 7 schematically illustrates an example of the cross-sectional structure of an interference pigment particle 22p. The interference pigment 22p includes, for example, a core portion 201 and a thin shell portion 202 covering the core portion 201. Both the core portion 201 and the shell portion 202 transmit visible light. The core portion 201 and the shell portion 202 are made of materials with different refractive indices. For example, the refractive index of the core portion 201 is smaller than that of the shell portion 202. Arrows AR2 and AR3 indicate incident light (second visible light) that enters the shell portion 202 of the interference pigment 22p. A portion of the incident light indicated by arrow AR3 travels through the shell portion 202 and is reflected by the core portion 201 to become reflected light indicated by arrow AR31. Furthermore, a portion of the incident light indicated by arrow AR2 is reflected by the surface of the shell portion 202 to become reflected light indicated by arrow AR21. The reflected light indicated by arrow AR21 and the reflected light indicated by arrow AR31 interfere constructively with each other, resulting in a strong visible interference light of a specific wavelength. For example, a blue interference pigment can be obtained by adjusting the thickness of the shell portion 202 so that the wavelength strengthened by interference is a blue wavelength. First visible light irradiated from the display screen 10 is also incident on the interference pigment 22p. The light incident on the interference pigment 22p indicated by arrow AR1 in FIG. 7 is the first visible light. The visible light indicated by arrow AR1 enters the interference pigment 22p, passes through the interference pigment 22p, and exits the interference pigment 22p in the opposite direction. This first visible light that passes through the interference pigment 22p is the transmitted light indicated by arrow AR11. The transmitted light indicated by arrow AR11 displays, for example, an icon 11 on the display screen 10.

[0022] As shown in FIG. 8 , when the reflection angle of the incident light IL1 and the reflected light RL1 striking the interference pigment 22p differs from the reflection angle of the incident light IL1w and the reflected light RL1w, the light path differs, and therefore the color of the interference light also changes. Furthermore, when the reflection angle of the incident light IL1 and the reflected light RL1 differs from the reflection angle of the incident light IL1w and the reflected light RL1w, the reflectivity also differs, and therefore the magnitude of the spectral components contained in the interference light also changes. Furthermore, when the reflection angle differs, the proportion of spectral components at each frequency contained in the interference light also changes. For example, because the reflection angle of the incident light IL1w and the reflected light RL1w is larger than the reflection angle of the incident light IL1 and the reflected light RL1, the reflected light RL1w is stronger than the reflected light RL1. Furthermore, the magnitude of the spectral components contained in the reflected light RL1w differs at each frequency, resulting in a different color tone compared to the reflected light RL1. The pattern layer 22 may be constructed by stacking multiple layers containing interference pigments 22p that emit different colors.

[0023] (2-3) Matte Layer 23 The matte layer 23 can be formed by dispersing transparent fine particles in a transparent resin. Examples of transparent resins include acrylic resin, silicone resin, polyethylene resin, polypropylene resin, polyester resin, polycarbonate resin, epoxy resin, and polyurethane resin. Examples of transparent fine particles include acrylic crosslinked particles, styrene crosslinked particles, talc, glass beads, and silicone particles. The transparent fine particles used to form the matte layer 23 have an average particle diameter of 2 to 20 μm. The transparent fine particles may include, for example, two or more types of particles with a difference in average particle diameter of 1.5 μm or more. In addition to using transparent fine particles to roughen the surface of the matte layer 23 to cause diffuse reflection, the matte layer 23 may also be configured to roughen the surface of a transparent or translucent layer without using fine particles to cause diffuse reflection.

[0024] (2-4) Gloss Layer 24 As shown in FIG. 2, the gloss layer 24 has convex portions 24p and concave portions 24r. The gloss layer 24 has a wavy shape with repeated concave portions 24r and convex portions 24p. The pattern formed by the repeated concave portions 24r and convex portions 24p is, for example, a geometric pattern as shown in FIG. 5. As shown in FIG. 6, such a pattern formed by the gloss layer 24 is viewed superimposed on the display on the display screen 10. While such a pattern formed by the repeated concave portions 24r and convex portions 24p can impart a predetermined design, it is also important to prevent a decrease in visibility due to the repeated concave portions 24r and convex portions 24p. It is also important to impart a desired tactile feel to the surface-exposed region EX by the repeated concave portions 24r and convex portions 24p of the gloss layer 24. The tactile feel of the concave portions 24r and convex portions 24p of the gloss layer 24 becomes less noticeable as the gradation of the concave portions 24r approaches 100%. Therefore, the gradation of the recesses 24r of the gloss layer 24 is preferably set to 60% or less. To improve visibility, the haze value of the recesses 24r and the protrusions 24p is preferably set to 30% or more. For example, in the example shown in FIG. 3 , the gradation of the recesses 24r of the gloss layer 24 is set to 40%. The gradation of the dots D1 of the recesses 24r can be adjusted by, for example, adjusting the amount of ink used to print the recesses 24r when forming the gloss layer 24 by printing. This printing method allows the recesses 24r and the protrusions 24p of the gloss layer 24 to be printed in one go, saving time and effort. For example, if the amount of ink per unit area where the recesses 24r are printed is half the amount of ink per unit area where the protrusions 24p are printed, the gradation of the dots D1 of the recesses 24r will be 50% (half). Resins used for the gloss layer 24 include, for example, polyvinyl resins, polyamide resins, polyacrylic resins, polyurethane resins, polyvinyl acetal resins, polyester urethane resins, cellulose ester resins, and alkyd resins.

[0025] Second Embodiment (3) Overall Configuration In the smartphone 1 and cover panel 20, which are examples of the display device of the first embodiment, the recesses 24r and the protrusions 24p are formed by adjusting the gradation of the recesses 24r of the gloss layer 24. Therefore, the surfaces of both the recesses 24r and the protrusions 24p are formed with the material forming the gloss layer 24. As shown in FIG. 9 , in the cover panel 20 of the second embodiment, the protrusions 24p are formed with the gloss layer 24. However, the gloss layer 24 is not formed on the recesses 23r. In other words, by setting the gradation of the recesses 24r of the gloss layer 24 of the first embodiment to 0%, the cover panel 20 of the second embodiment has an uneven surface in the surface-exposed region EX. In other words, the bottom surface of the recesses 23r of the cover panel 20 of the second embodiment is formed with the surface of the matte layer 23. The base film 21 and the design layer 22 of the cover panel 20 of the second embodiment can be configured in the same manner as the base film 21 and the design layer 22 of the cover panel 20 of the first embodiment. In the cover panel 20 of the second embodiment, the bottom surface of the recess 23r is the surface of the matte layer 23, so the laminate consisting of the base film 21 and the matte layer 23 has a haze value set to 65% or more and 80% or less. The haze value of the cover panel 20 is configured to be 40% or more and 85% or less. As in the first embodiment, to obtain even better visibility, it is more preferable that the haze value of the cover panel 20 be configured to be 60% or more and 70% or less.

[0026] (4) Modifications (4-1) Modification A As shown in FIG. 10 , a cover panel 20 can be formed on a smartphone 1, which is a display device, using a decorative sheet 50. The decorative sheet 50 shown in FIG. 10 includes a base film 21, a pattern layer 22, a matte layer 23, and a glossy layer 24, similar to those in the first embodiment. In forming the cover panel 20, the decorative sheet 50 is cut out from an original roll of the decorative sheet 50 in a size required for the cover panel 20. An adhesive 18 for dry lamination is applied to the pattern layer 22 of the decorative sheet 50. The decorative sheet 50 with the adhesive 18 applied thereto is superimposed on a molding resin 19, and pressure is applied. The decorative sheet 50 and the molding resin 19 are bonded together by the pressure, and as shown in FIG. 11 , the cover panel 20 is provided on the molding resin 19. The molding resin 19 and the cover panel 20 are part of the smartphone 1.

[0027] (4-2) Modification B The decorative sheet 50 shown in FIG. 12 includes the same base film 21, pattern layer 22, matte layer 23, and gloss layer 24 as in the second embodiment. The decorative sheet 50, coated with a dry lamination adhesive 18, is stacked on a molded resin 19 and pressurized to form a cover panel 20 on the molded resin 19, similar to the smartphone 1 shown in FIG. 11 . However, the decorative sheet 50 shown in FIG. 12 has a larger uneven surface caused by the gloss layer 24 than the decorative sheet 50 shown in FIG. 10 . Therefore, the decorative sheet 50 shown in FIG. 10 has a lower risk of air bubbles Bu (see FIGS. 13 and 14 ) remaining than the decorative sheet 50 shown in FIG. 12 . (4-3) Modification C In the first and second embodiments described above, a matte layer 23 is formed on the base film 21. However, as shown in FIG. 15 , the base film 21A may also be configured to function as a matte layer. For example, a matte finish may be imparted to the substrate film 21 by using a substrate film 21 in which transparent fine particles are kneaded. In other words, a substrate film 21A having a matte finish may be used as a laminate consisting of the substrate film 21 and the matte layer 23. (4-4) Variation D In the first and second embodiments described above, the icons 11 displayed on the display screen 10 of the smartphone 1 were described. However, even if the techniques described in the first and second embodiments are applied to a case where an icon is displayed using, for example, a black concealing layer patterned in the shape of an icon, it is possible to prevent the icons from becoming difficult to see due to the unevenness of the matte layer 23 and the glossy layer 24. Figures 16 and 17 show an example in which an icon is displayed using light emitted from an LED 80 toward the matte layer 23 and the glossy layer 24 of the cover panel 20. An icon-shaped pattern 25a is formed on the concealing layer 25 provided between the LED 80 and the matte layer 23 and the glossy layer 24. The light from the LED 80 passes through this pattern 25a, thereby displaying the icon in the surface-exposed region EX. The difference between the cover panels 20 in FIG. 16 and FIG. 17 is whether or not a transparent polycarbonate sheet 26 is provided between the concealing layer 25 and the molding resin 19 .Another transparent sheet may be provided instead of the polycarbonate sheet 26. The concealing layer 25 may be formed, for example, by printing with black ink. Transparent or translucent glass may be used instead of the transparent or translucent molding resin 19. (4-5) Variation E In the second embodiment, the matte layer 23 is formed by laminating it onto the base film 21. However, the cover panel may also be manufactured by transfer printing. Figure 18 schematically shows the process for manufacturing the cover panel 20 by transfer printing. First, a matte ink 61 and a glossy ink 62 are printed on a prepared carrier film 60, for example, by gravure printing. In the example shown in Figure 18, the matte ink 61 is printed on the entire surface of the carrier film 60, and the glossy ink 62 is printed partially so as to overlap the matte ink 61. Next, a transparent resin is coated to form a top layer 63. Furthermore, a design layer 64 is printed on the coated top layer 63, for example, by gravure printing. The top layer 63 and the design layer 64 are transferred to the molding resin 19, while the carrier film 60, the matte ink 61, and the glossy ink 62 do not remain on the cover panel 20. The surface condition of the matte ink 61 is transferred to the convex surface 63x of the top layer 63 included in the cover panel 20. The surface condition of the glossy ink 62 is transferred to the concave surface 63y of the top layer 63. As a result, the haze value of the surface-exposed region EX consisting of the convex surface 63x and the concave surface 63y can be set to 40% or more and 85% or less. The haze value of the convex surface 63x can be set to 65% or more and 80% or less. The haze value of the concave surface 63y can be set to 30% or more and 60% or less. Examples of resins that can be used for the top layer 63 include acrylic resin, silicone resin, polyethylene resin, polypropylene resin, polyester resin, polycarbonate resin, epoxy resin, and polyurethane resin.

[0028] (5) Features (5-1) The cover panel 20 of a smartphone 1, which is a display device, or the decorative sheet 50 used in the smartphone 1, is provided for a display screen 10 that emits first visible light to visually display information or images, and is arranged in an exposed surface region EX that transmits the first visible light emitted from the display screen 10. The cover panel 20 includes a transparent or translucent base film 21, a design layer 22, a transparent or translucent matte layer 23, and a transparent or translucent glossy layer 24. The base film 21 has a first main surface 21a onto which the first visible light emitted from the display screen 10 is incident, and a second main surface 21b from which the first visible light exits. The design layer 22 is arranged on the side of the first main surface 21a of the base film 21, and has a design that is colored with an interference pigment 22p that develops color due to interference of reflected light of second visible light that is incident on the exposed surface region EX from the outside. The matte layer 23 is disposed on the second main surface 21b side of the base film 21 and is a layer for matting the surface exposed region EX. The gloss layer 24 is disposed on the layer surface 23s of the matte layer 23. The gloss layer 24 is a layer for forming convex portions 24p and concave portions 24r in the surface exposed region EX to increase the surface roughness of the surface exposed region EX compared to when the gloss layer 24 is not present, and is configured so that the haze value of the surface exposed region EX is 40% or more and 85% or less. By setting the haze value of the cover panel 20 or decorative sheet 50 including the pattern layer 22 colored with interference pigments 22p to 40% or more and 85% or less, the gloss layer 24 can impart a tactile feel to the surface exposed region EX with the recesses 24r and protrusions 24p, and even for displays where the visibility of transmitted light is slightly reduced by the interference pigments 22p, the boundaries between the protrusions 24p and recesses 24r can be made less noticeable, thereby improving the visibility of the cover panel 20 or decorative sheet 50.

[0029] (5-2) The cover panel 20 shown in FIG. 2 or the decorative sheet 50 shown in FIG. 10 is configured such that the recesses 24r and protrusions 24p are formed by a gloss layer 24 having a wavy shape in which the recesses 24r and protrusions 24p are repeated. In the cover panel 20 of FIG. 2 or the decorative sheet 50 of FIG. 10, the gloss layer 24 can provide a difference in haze value between the protrusions 24p and the recesses 24r, making it easy to set the haze value of the cover panel 20 or the decorative sheet 50 to an appropriate value and facilitating improvement of visibility. The cover panel 20 of FIG. 2 or the decorative sheet 50 of FIG. 10 is used, for example, in a smartphone 1, but may also be used in display devices other than the smartphone 1. (5-3) In the cover panel 20 of FIG. 2 or the decorative sheet 50 of FIG. 10, the gloss layer 24 is configured such that the gradation of the recesses 24r is 30% or more and 60% or less. 2 or the decorative sheet 50 of Fig. 10 has a configuration that makes it easy to appropriately set the difference in haze value between the convex portion 24p and the concave portion 24r, and makes it easy to improve visibility. The cover panel 20 of Fig. 2 or the decorative sheet 50 of Fig. 10 is used for, for example, the smartphone 1, but may also be used for display devices other than the smartphone 1.

[0030] (5-4) In the cover panel 20 shown in FIG. 9 or the decorative sheet 50 shown in FIG. 12, the bottom surface of the recess 23r is formed by the surface of the matte layer 23. In the cover panel 20 of FIG. 9 or the decorative sheet 50 of FIG. 12, the haze value of the bottom surface of the recess 23r can be set to the haze value of the matte layer 23, making it easier to set the haze value of the recess 23r and to improve visibility. (5-5) In the cover panel 20 of FIG. 9 or the decorative sheet 50 of FIG. 12, the haze value of the laminate consisting of the base film 21 and the matte layer 23 is set to be 65% or more and 80% or less. Therefore, in the cover panel 20 of FIG. 9 or the decorative sheet 50 of FIG. 12, blurring of the display on the display screen 10 can be suppressed, significantly improving visibility.

[0031] (5-6) The cover panel 20 or the decorative sheet 50 preferably has a haze value of 60% or more and 70% or less. Setting the haze value of the cover panel 20 or the decorative sheet 50 in this manner reduces the visibility of the boundaries between the recesses 24r, 23r and the protrusions 24p while suppressing a decrease in the display contrast of the display screen 10, thereby significantly improving visibility. Figures 19 to 21 show an enlarged view of one icon on a display screen in which the gloss layer forms a geometric pattern. Figure 19 shows an example of a conventional display screen 110. Figure 20 shows the display screen 10 of the smartphone 1 according to the first embodiment. Figure 21 shows the display screen 10 of the smartphone 1 according to the second embodiment. As shown in Figure 19, the uneven pattern caused by the formation of the gloss layer on the icon 111 is visible within the icon, detracting from its aesthetic appearance. Furthermore, the text 112 below the icon in Figure 19 is unclear at the boundary between the convex and concave portions. Comparing Figures 19, 20, and 21, it can be seen that in Figures 20 and 21, the boundary between the convex and concave portions is less visible due to the formation of the gloss layer 24, and the text is easier to read. This indicates that contrast is improved by adopting the configuration of the first or second embodiment. Figures 22 to 24 show an enlarged view of one icon on the display screen when the gloss layer depicts a wood grain pattern. Figure 22 shows an example of a conventional display screen. Figure 23 shows the display screen 10 of the smartphone 1 according to the first embodiment. Figure 24 shows the display screen 10 of the smartphone 1 according to the second embodiment. As can be seen from Figure 22, the formation of the gloss layer on the icon makes the icon and text blurred and difficult to see. 22 with 23 and 24, it can be seen that even with the wood grain pattern of the gloss layer 24 in Figs. 23 and 24, blurring of the outlines of the icons and characters is suppressed, and that contrast is improved by adopting the configuration of the first or second embodiment. Figs. 25 to 27 show enlarged views of an icon when the gloss layer depicts a wood grain pattern and the icon is displayed using a concealing layer. Fig. 25 shows an example of an icon pattern 125a on an automotive panel 170 using a conventional concealing layer.FIG. 26 shows an icon pattern 25a (see FIGS. 16 and 17 ) on an automobile panel 70 having a wood grain pattern created by the gloss layer 24 according to the first embodiment. FIG. 27 shows an icon pattern 25a (see FIGS. 16 and 17 ) on an automobile panel 70 having a wood grain pattern created by the gloss layer 24 according to the second embodiment. As shown in FIG. 25 , the wood grain pattern appears on the icon pattern 125a and its surroundings due to the formation of the gloss layer, detracting from the aesthetic appearance of the icon pattern 125a. Furthermore, comparing FIGS. 25 with FIGS. 26 and 27 , it can be seen that the icon pattern 25a and its surroundings are clean despite the wood grain pattern of the gloss layer 24, and that adopting the configuration of the first or second embodiment improves aesthetics. While the first and second embodiments of the present invention have been described above, the present invention is not limited to these embodiments and various modifications are possible without departing from the spirit and scope of the invention. In particular, the multiple embodiments and modifications described herein can be combined as needed.

[0032] REFERENCE SIGNS LIST 1 Smartphone 10 Display screen 20 Cover panel 21 Base film 22 Design layer 23 Matte layer 24 Glossy layer 24p Convex portion 24r, 23r Concave portion 50 Decorative sheet EX Surface exposed area

Claims

1. A cover panel provided for a display screen which radiates a first visible light to visually display information or images, and placed on an exposed surface area of ​​a display device which transmits the first visible light radiated from the display screen, comprising: a transparent or translucent base film having a first main surface into which the first visible light radiated from the display screen is incident, and a second main surface from which the first visible light is emitted; a pattern layer disposed on the first main surface side of the base film, and having a pattern colored with an interference pigment which develops its color by interference of reflected light of second visible light which is incident on the exposed surface area from the outside; a transparent or translucent matte layer disposed on the second main surface side of the base film, for matting the exposed surface area; and a transparent or translucent gloss layer disposed on the layer surface of the matte layer, the gloss layer being a layer which forms convex portions and concave portions in the exposed surface area, thereby increasing the surface roughness of the exposed surface area compared to a case in which the gloss layer is not present, and the cover panel is configured so that the haze value of the exposed surface area is 40% or more and 85% or less.

2. The cover panel according to claim 1, wherein the recesses and protrusions are made of the gloss layer having a wavy shape in which the recesses and protrusions are repeated.

3. A cover panel as described in claim 2, wherein the gloss layer is configured so that the gradation of the dot portion in the recess where the dots are formed is 30% or more and 60% or less.

4. The cover panel according to claim 3, wherein the bottom surface of the recess is formed by the surface of the matte layer.

5. The cover panel according to claim 4, wherein the region of the laminate consisting of the base film and the matte layer has a haze value of 65% or more and 80% or less.

6. A cover panel according to any one of claims 1 to 5, wherein the haze value of the exposed surface area is configured to be 60% or more and 70% or less.

7. A decorative sheet provided for a display screen which radiates a first visible light to visually display information or images, and placed on an exposed surface area of ​​a display device which transmits the first visible light radiated from the display screen, comprising: a transparent or semi-transparent base film having a first main surface into which the first visible light radiated from the display screen is incident, and a second main surface from which the first visible light exits; a pattern layer placed on the first main surface side of the base film, having a pattern colored with an interference pigment which develops its color by interference of reflected light of second visible light which is incident on the exposed surface area from the outside; a transparent or semi-transparent matte layer placed on the second main surface side of the base film, for matting the exposed surface area; and a transparent or semi-transparent gloss layer placed on the layer surface of the matte layer, the gloss layer being a layer which forms convex portions and concave portions in the exposed surface area, thereby increasing the surface roughness of the exposed surface area compared to the case where the gloss layer is not present; and the decorative sheet is configured so that a haze value of a portion corresponding to the exposed surface area is 40% or more and 85% or less.

8. A display device comprising: a display screen that radiates a first visible light to visually display information or an image; and a cover panel that is disposed on an exposed surface area of ​​the display screen and transmits the first visible light radiated from the display screen, wherein the cover panel comprises: a transparent or translucent base film having a first main surface into which the first visible light radiated from the display screen is incident and a second main surface from which the first visible light exits; a pattern layer that is disposed on the first main surface side of the base film and has a pattern colored with an interference pigment that develops its color by interference of reflected light of second visible light that is incident on the exposed surface area from the outside; a transparent or translucent matte layer that is disposed on the second main surface side of the base film and provides a matte finish to the exposed surface area; and a transparent or translucent gloss layer that is disposed on a layer surface of the matte layer, wherein the gloss layer is a layer that forms convex portions and concave portions in the exposed surface area to increase the surface roughness of the exposed surface area compared to a case in which the gloss layer is not present, and the haze value of the exposed surface area of ​​the cover panel is configured to be 40% or more and 85% or less.

Images