Decorative sheet

Abstract

A decorative sheet (1) comprises: a skin layer (3) that has light transmittance; an intermediate layer (4) that is disposed on the back side of the skin layer (3) and has light transmittance; a design layer (5) that is disposed on the back side of the intermediate layer (4); and a base layer (6) that is disposed on the back side of the design layer (5) and has light transmittance. When viewed from the front side, the design layer (5) has a shielding part (50) and an opening (51) disposed adjacent to the shielding part (50) via a boundary (A). When viewed from the front side, a plurality of dot parts (510) are disposed in the opening (51). The plurality of dot parts (510) are disposed so as to be denser at the boundary (A) and sparser on the inside of the opening part (51). The opening (51) has higher light transmittance than the shielding part (50) and the dot part (510). The dot part (510) has the same light transmittance as the shielding part (50) or higher light transmittance than the shielding part (50).

Description

Decorative sheet

[0001] The present disclosure relates to a decorative sheet used in, for example, vehicle interior fittings.

[0002] In the field of vehicle interiors, development is progressing on decorative sheets that can switch designs visible from inside the vehicle cabin by turning on and off a backlight. For example, Patent Document 1 discloses a display device that includes a surface protective layer, a pattern layer (design layer) and a gap, a substrate, a light-controlling sheet, a light-emitting display (display), and a display control device. The surface protective layer, the pattern layer and the gap, the substrate, the light-controlling sheet, and the light-emitting display are layered in the same order from the front side (inside the vehicle cabin) to the back side. The display control device is arranged separately from these components.

[0003] The surface protection layer is colorless and transparent. A pattern such as a wood grain vessel pattern or a marble pattern is printed on the pattern layer. The pattern layer is printed on the surface of the substrate. The voids are juxtaposed to the pattern layer. The voids correspond to the portions of the substrate surface where the pattern layer is not printed.

[0004] The display control device can adjust the light transmittance of the light-adjusting sheet depending on whether the light-emitting display body is on or off. Specifically, the display control device can adjust the light-adjusting sheet so that it transmits light when the light-emitting display body is on and does not transmit light when the light-emitting display body is off. When the light-emitting display body is on, the light-adjusting sheet transmits light, making it easy for the design of the pattern layer to appear on the surface of the surface protection layer. On the other hand, when the light-emitting display body is off, the light-adjusting sheet does not transmit light, making it difficult for the design of the pattern layer to appear on the surface of the surface protection layer.

[0005] Japanese Patent Application Laid-Open No. 2021-162723

[0006] However, according to the decorative sheet of the same document, when the light-emitting display is turned off, under certain conditions, the design of the pattern layer may be easily visible on the surface of the surface protective layer. That is, when the light-emitting display is turned off, a portion of the light from the outside (front side of the decorative sheet) is reflected by the surface of the substrate. A portion of the light travels through the surface protective layer → void → substrate surface → void again → surface protective layer again, and is visible to the user. Another portion of the light from the outside is reflected by the backside of the surface protective layer (without reaching the surface of the substrate) and is visible to the user. Here, if the difference between the reflection on the surface of the substrate and the reflection on the backside of the surface protective layer is excessively large, the void is easily visible from the outside. Therefore, the present disclosure aims to provide a decorative sheet in which the openings in the design layer are less visible when the backlight is turned off.

[0007] (1) In order to solve the above problem, the decorative sheet of the present disclosure is a decorative sheet comprising a light-transmitting surface layer, a light-transmitting intermediate layer disposed on the back side of the surface layer, a design layer disposed on the back side of the intermediate layer, and a light-transmitting base layer disposed on the back side of the design layer, wherein, as viewed from the front side, the design layer has a shielding portion and an opening disposed adjacent to the shielding portion via a boundary, and as viewed from the front side, a plurality of dot portions are disposed within the opening, and the plurality of dot portions are disposed so as to become more densely spaced from the boundary toward the inside of the opening, the opening has a higher light transmittance than the shielding portion and the dot portions, and the dot portions have the same or higher light transmittance as the shielding portion.

[0008] Let us assume that no dots are arranged within the openings. In this case, when the backlight is off, a portion of the light incident on the decorative sheet from the front side of the skin layer is reflected by the surface of the shielding portion (shielding portion reflection) and is visible to the user. Also, when the backlight is off, another portion of the light incident on the decorative sheet from the front side of the skin layer passes through the openings and is reflected by the surface of the base layer (base layer reflection) and is visible to the user.

[0009] A difference occurs between the shielding portion reflection and the base layer reflection due to the difference in light reflectance between the shielding portion surface and the base layer surface, etc. Therefore, the boundary between the shielding portion and the opening is easily visible to the user.

[0010] In this regard, according to the present configuration, a plurality of dots are arranged within the opening. The dots are arranged from dense to sparse from the boundary between the shielding portion and the opening toward the inside of the opening. As described above, the boundary between the shielding portion and the opening is easily visible when the backlight is turned off. By densely arranging a plurality of dots near the boundary, the boundary can be blurred. Therefore, the boundary can be prevented from being visible to the user.

[0011] Furthermore, at least one of absorption, attenuation, and reflection of light reflected from the surface of the base layer occurs on the side surfaces of the dots (surfaces connecting the front and back surfaces), which makes it possible to blur the boundary (outer edge of the dots) between the dots and the areas within the opening where no dots are located (dot-absent areas).

[0012] (1-1) In the configuration of (1) above, it is preferable that the base layer is made of a thermoplastic elastomer and has a light-diffusing property. The base layer made of a thermoplastic elastomer has a large number of pores. Macroscopically, the surface of the base layer is white. Therefore, the surface of the base layer is likely to reflect light. Therefore, when the backlight is turned off, the boundary between the shielding portion and the opening is easily visible. The decorative sheet of the present disclosure is suitable for a decorative sheet having such a highly light-reflecting base layer.

[0013] (2) In the configuration of (1) above, when viewed from the front side, the opening is partitioned into an outer dot area arranged adjacent to the boundary and an inner dot area arranged adjacent to the outer dot area, and it is preferable that the outer dot area has multiple dot portions arranged more densely than the inner dot area.

[0014] According to this configuration, the opening is divided into an outer dot area where the dots are densely arranged, and an inner dot area where the dots are sparsely arranged. These two types of dot areas allow the dots to be arranged in a manner that increases from dense to sparse from the boundary toward the inside of the opening.

[0015] (3) In the configuration of (2) above, the direction perpendicular to the extension direction of the boundary is the width direction, and of the widthwise ends of the outer dot area, the end on the shielding portion side is the outer end and the end on the opening side is the inner end, and the outer end is the boundary, and the total widthwise length of the opening is 100%, and it is better to configure the inner end to be positioned within 33% of the boundary in the width direction.

[0016] With this configuration, compared to when the entire width of the opening is 100% and the inner edge is positioned more than 33% widthwise from the boundary, the width of the outer dot area (the area where the dots are densely arranged) can be narrowed and the width of the inner dot area (the area where the dots are sparsely arranged) can be widened. This allows for concentrated blurring of the boundary. Furthermore, excessive reduction in the light transmittance of the opening can be prevented.

[0017] (4) In the configuration of (2) above, it is preferable that the arrangement density of the plurality of dot portions in the outer dot area gradually decreases from the boundary toward the inside of the opening when viewed from the front side.

[0018] Let us assume that the arrangement density of the dots changes suddenly from the boundary between the shielding portion and the opening toward the inside of the opening. In this case, when the backlight is turned off, the boundary where the arrangement density of the dots changes (hereinafter referred to as the "arrangement density boundary") becomes more easily visible to the user. In this regard, with this configuration, the arrangement density of the dots gradually decreases from the boundary between the shielding portion and the opening toward the inside of the opening. This makes it possible to blur the arrangement density boundary.

[0019] Furthermore, the light transmittance differs between areas where the density of the dots is high and areas where it is low. Therefore, if the density of the dots changes suddenly from the boundary between the shielding portion and the opening toward the inside of the opening, the difference in light transmittance becomes large. Therefore, when the backlight is turned on, the user can easily see the difference in luminous intensity. In this regard, with this configuration, the density of the dots gradually decreases from the boundary between the shielding portion and the opening toward the inside of the opening. Therefore, the difference in light transmittance is small. Therefore, when the backlight is turned on, the user cannot easily see the difference in luminous intensity.

[0020] (5) In the configuration of (2) above, it is preferable that the arrangement density of the plurality of dots in the outer dot area is uniform when viewed from the front side. This configuration can prevent the occurrence of boundaries between the arrangement densities of the plurality of dots in the outer dot area. Furthermore, since boundaries between the arrangement densities of the plurality of dots are unlikely to occur, light transmittance tends to be uniform throughout the entire outer dot area. Therefore, when the backlight is turned on, the user is less likely to notice differences in luminous intensity.

[0021] (6) In the configuration of (2) above, it is preferable that, when viewed from the front side, the area of ​​the inner dot area is 100%, and the total area of ​​the multiple dot portions in the inner dot area is 25% or more and 50% or less.

[0022] This configuration can prevent the opening from being seen by a user when the backlight is off, compared to when the total area of ​​the dot portions is less than 25%. Also, it can prevent a decrease in the light transmittance of the opening when the backlight is on, compared to when the total area of ​​the dot portions is more than 50%.

[0023] (7) In the configuration of (1) above, it is preferable that the diameter of the circumscribing circle of the dot portion is 1.5 mm or less when viewed from the front side. With this configuration, compared to when the diameter of the circumscribing circle exceeds 1.5 mm, it is possible to prevent the dot portion itself from being visible to the user when the backlight is turned off.

[0024] (8) In the configuration of (1) above, it is preferable that the opening be strip-shaped when viewed from the front side, and that the short-side length of the opening be 3 mm or more. Here, "strip-shaped" refers to an aspect ratio of the opening (short-side length:long-side length) = (exceeding 1:1). When the short-side length of the opening is 3 mm or more, the boundary between the shielding portion and the opening is more easily visible to the user when the backlight is off. With this configuration, multiple dots can be arranged in an area where the boundary blurring effect can be effectively achieved (an area where the short-side length of the opening is 3 mm or more). Therefore, the boundary between the shielding portion and the opening can be prevented from being visible to the user when the backlight is off.

[0025] (9) In the configuration of (1) above, it is preferable that the visible light transmittance of the intermediate layer be 3% or more and 30% or less. In the present disclosure, "visible light" refers to electromagnetic waves in a wavelength range that is perceived as light by the human eye. The wavelength range of visible light is, for example, 360 nm or more and 830 nm or less. Furthermore, "visible light transmittance" τ refers to the percentage of visible light that passes through a sample (e.g., an intermediate layer). The visible light transmittance τ (%) is expressed as (I / I) × 100, where I0 is the luminous intensity of incident light and I is the luminous intensity of light that has passed through the sample. This configuration improves the visibility of the opening when the backlight is on, compared to when the visible light transmittance is less than 3%. Furthermore, compared to when the visible light transmittance is more than 30%, it is possible to suppress the opening from being visible through the surface of the skin layer when the backlight is off.

[0026] (10) In the configuration of (1), it is preferable to arrange the backlight in an interior part of a vehicle. With this configuration, by switching the backlight on and off, it is possible to give the interior part a dual-faceted design.

[0027] According to the decorative sheet of the present disclosure, it is possible to prevent the openings in the design layer from being visible when the backlight is turned off.

[0028] FIG. 1 is a partial perspective view of a door trim in which a decorative sheet of a first embodiment is disposed. FIG. 2 is a perspective view of the interior of frame II in FIG. 1. FIG. 3 is an exploded perspective view of the interior of frame II in FIG. 1. FIG. 4 is a surface view of the design layer of the interior of frame II in FIG. 1. FIG. 5 is an enlarged view of the interior of frame V in FIG. 4. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5. FIG. 7 is a partial surface view of the design layer of a decorative sheet of a second embodiment. FIG. 8 is a partial surface view of the design layer of a decorative sheet of a third embodiment. FIG. 9(A) is a surface view of a dot portion of a decorative sheet of another embodiment (part 1). FIG. 9(B) is a surface view of a dot portion of a decorative sheet of another embodiment (part 2). FIG. 9(C) is a surface view of a dot portion of a decorative sheet of another embodiment (part 3). FIG. 9(D) is a surface view of a dot portion of a decorative sheet of another embodiment (part 4).

[0029] Hereinafter, an embodiment of the decorative sheet of the present disclosure will be described.

[0030] <First embodiment> Fig. 1 shows a partial perspective view of a door trim in which a decorative sheet of this embodiment is arranged. Fig. 2 shows a perspective view of the interior of frame II in Fig. 1. Fig. 3 shows an exploded perspective view of the interior of frame II in Fig. 1. Fig. 4 shows a surface view of the design layer within frame II in Fig. 1. Fig. 5 shows an enlarged view of the interior of frame V in Fig. 4. Fig. 6 shows a cross-sectional view taken along the line VI-VI in Fig. 5. In these figures, the front-to-rear direction corresponds to the "boundary extension direction" of the present disclosure, and the left-to-right direction corresponds to the "width direction" and "short direction" of the present disclosure, respectively.

[0031] (Arrangement and configuration of decorative sheet) First, the arrangement and configuration of the decorative sheet of this embodiment will be described. As shown in FIG. 1 , the decorative sheet 1 is arranged on a door trim 9 in the vehicle interior. The door trim 9 is included in the concept of "interior member" in this disclosure. As shown in FIGS. 1 to 6 , the door trim 9 includes the decorative sheet 1 and a light source unit 8. The decorative sheet 1 and the light source unit 8 are layered in this order from the front side (upper side, inside the vehicle interior) to the back side (lower side, outside the vehicle interior).

[0032] As shown in Figures 3 and 6, the decorative sheet 1 comprises, from the front side to the back side, a skin layer 3, an intermediate layer 4, a design layer 5, and a base layer 6. As shown in Figure 1, the surface (top surface) of the skin layer 3 is exposed to the interior of the vehicle. The skin layer 3 is made of synthetic leather and has a layered structure. The skin layer 3 is light-transmitting and flexible. As shown in Figure 6, the skin layer 3 has an uneven grained portion 31 on its surface. The grained portion 31 is disposed over the entire surface of the skin layer 3. Light is irradiated onto the design layer 5 (described later) from a light source unit 8 on the back side through the base layer 6 (described later). The light causes the design of the design layer 5 (openings 51, dots 510, etc.) to be displayed on the surface of the skin layer 3.

[0033] As shown in Figures 3 and 6, the intermediate layer 4 is disposed on the back side of the surface layer 3. The intermediate layer 4 is made of light-transmitting ink and has a layered structure. The intermediate layer 4 is light-transmitting and flexible. The intermediate layer 4 has lower light transmittance than the surface layer 3. The intermediate layer 4 is semi-transparent with a smoky color. The intermediate layer 4 is colored and transparent.

[0034] As shown in Figures 3 and 6, the design layer 5 is disposed on the back side of the intermediate layer 4. The design layer 5 is layered. The design layer 5 is flexible. The design layer 5 has higher light transmittance than the intermediate layer 4. As shown in Figures 3 to 5, when viewed from the front side, the design layer 5 has two shielding portions 50, an opening 51, and a boundary A. The two shielding portions 50 are disposed along both the left and right edges of the design layer 5. The shielding portions 50 are strip-shaped and extend in the front-to-rear direction. The shielding portions 50 are made of light-blocking (light-opaque) ink and have light-blocking properties.

[0035] As shown in FIG. 5 , the opening 51 is disposed between two left and right shielding portions 50 (inside in the left-right direction). The opening 51 is a space and is light-transmitting. The opening 51 is disposed adjacent to the shielding portion 50 via a boundary A. The opening 51 has a strip shape extending in the front-to-rear direction. When viewed from the front side, a plurality of dot portions 510 are dispersed within the opening 51. Specifically, the plurality of dot portions 510 are disposed within the opening 51 so that the density of the dot portions 510 increases from the boundary A toward the inside of the opening 51 (the center of the opening 51 in the left-to-right direction). The dot portions 510 are oval-shaped and elongated in the left-to-right direction. The areas of the plurality of dot portions 510 are uniform. The dot portions 510 are made of light-blocking ink and have light-blocking properties. The opening 51 (more specifically, the portion of the opening 51 where the dot portions 510 are not disposed; the dot-absent portion) has higher light transmittance than the shielding portion 50 and the dot portions 510. The dot portions 510 have the same light transmittance as the shielding portions 50 or higher than the shielding portions 50. That is, the relationship of high and low light transmittance is "openings 51 > dot portions 510 ≧ shielding portions 50" in ascending order.

[0036] The opening 51 is partitioned into two outer dot areas B on the left and right, and an inner dot area C. The outer dot area B is located within the opening 51, adjacent to the boundary A. The inner dot area C is located within the opening 51, adjacent to the outer dot area B, and on the left-right inside of the outer dot area B. The multiple dot sections 510 are densely arranged in the outer dot area B and sparsely arranged in the inner dot area C.

[0037] As shown in Figure 6, the base layer 6 is disposed on the back side of the design layer 5. The base layer 6 is made of a thermoplastic elastomer and has flexibility, light transparency, and light diffusion properties. The light from the light source 80 is diffused by the base layer 6 in the layer-wise direction (the layer development direction; a direction intersecting the stacking direction (vertical direction); a surface direction). As a result, the entire surface of the base layer 6 emits light.

[0038] As shown in Fig. 6, the light source unit 8 is disposed on the back side of the base layer 6 of the decorative sheet 1. The light source unit 8 includes a plurality of light sources (LEDs) 80. The plurality of light sources 80 are distributed along the entire layer direction of the light source unit 8. Light from the light sources 80 reaches the surface of the door trim 9 via the base layer 6, the design layer 5, the intermediate layer 4, and the skin layer 3.

[0039] (Method for Manufacturing Decorative Sheet) Next, a method for manufacturing the decorative sheet of this embodiment will be described. The method for manufacturing the decorative sheet 1 includes an intermediate layer printing step, a design layer printing step, and a base layer arranging step. This manufacturing method is performed with the decorative sheet 1 shown in FIGS. 1 to 4 turned upside down. In the intermediate layer printing step, an intermediate layer 4 is printed on the back surface (top surface) of the skin layer 3 with the grained portion 31 using a silk screen printer. If the intermediate layer 4 has a multi-layer structure (e.g., a structure having a top layer (transparent layer) and a back layer (colored layer)), each layer is printed in order. In the design layer printing step, a design layer 5 is printed on the back surface (top surface) of the intermediate layer 4 using a silk screen printer. Specifically, two shielding portions 50 are printed on both the left and right sides of the opening 51, and multiple dot portions 510 are printed within the opening 51. In the base layer arranging step, a pre-formed base layer 6 is laminated on the back surface of the design layer 5.

[0040] (Effects) Next, the effects of the decorative sheet of this embodiment will be described. Assume that no dots 510 are arranged within the openings 51. In this case, when the backlight is off (when the light source unit 8 is off), a portion of the light incident on the decorative sheet 1 from the front side of the skin layer 3 is reflected by the surface of the shielding units 50 (reflected by the shielding units 50) and is visible to the user. Furthermore, when the backlight is off, another portion of the light incident on the decorative sheet 1 from the front side of the skin layer 3 passes through the openings 51 and is reflected by the surface of the base layer 6 (reflected by the base layer 6) and is visible to the user.

[0041] Here, a difference occurs between the reflection of the shielding portion 50 and the reflection of the base layer 6 due to the difference in the light reflectance between the surface of the shielding portion 50 and the surface of the base layer 6. Therefore, the boundary A becomes more easily visible to the user.

[0042] In this regard, as shown in Fig. 5, according to the decorative sheet 1 of this embodiment, a plurality of dot portions 510 are arranged within the opening 51. The plurality of dot portions 510 are arranged so that the density of the dot portions 510 increases from a boundary A between the shielding portion 50 and the opening 51 toward the inside of the opening 51. By densely arranging the dot portions 510 near the boundary A, which is easily visible when the backlight is off, the boundary A can be blurred. Therefore, the boundary A can be prevented from being visible to the user.

[0043] Also, as shown in Figure 6, on the side surface of the dot portion 510 (the surface extending in the stacking direction (front-to-back direction, up-and-down direction); the surface connecting the front and back surfaces), at least one of absorption, attenuation, and reflection of light reflected on the surface of the base layer 6 occurs. Therefore, it is possible to blur the boundary (outer edge of the dot portion 510) between the dot portion 510 and the portion of the opening 51 where the dot portion 510 is not arranged (dot-absent portion).

[0044] The base layer 6 made of a thermoplastic elastomer has a large number of pores. Macroscopically, the surface of the base layer 6 is white. Therefore, the surface of the base layer 6 is likely to reflect light. Therefore, the boundary A is easily visible when the backlight is turned off. The decorative sheet 1 having such a highly light-reflecting base layer 6 is suitable for the decorative sheet of the present disclosure.

[0045] 5 , when viewed from the front side, the opening 51 is divided into an outer dot area B where the dots 510 are densely arranged, and an inner dot area C where the dots 510 are sparsely arranged. These two types of dot areas allow the dots 510 to be arranged so that they become more densely spaced from the boundary A toward the inside of the opening 51 (inside in the left-right direction).

[0046] As shown in FIG. 5 , of the two lateral ends of the outer dot area B, the end closest to the shielding portion 50 is designated as the outer end B1 (i.e., boundary A). Furthermore, of the two widthwise ends of the outer dot area B, the end closest to the opening 51 is designated as the inner end B2. If the overall lateral length of the opening 51 is taken as 100%, the inner end B2 is positioned within 33% of the boundary A inward in the lateral direction. Therefore, compared to when the inner end B2 is positioned more than 33% inward in the lateral direction from the boundary A, the width of the outer dot area B (the area where the dot portions 510 are densely arranged) can be narrowed and the width of the inner dot area C (the area where the dot portions 510 are sparsely arranged) can be widened. This allows for concentrated blurring of the boundary A. Furthermore, excessive reduction in the light transmittance of the opening 51 can be suppressed.

[0047] As shown in Figure 5, when viewed from the front side, two dot rows L1-L2 are arranged in the outer dot area B from the outer edge B1 (boundary A) to the inner edge B2. The two dot rows L1-L2 are aligned in the left-right direction. Each of the dot rows L1-L2 has a plurality of dot portions 510 arranged in a straight line (dotted line). Each of the dot rows L1-L2 extends in the front-to-rear direction.

[0048] In the two dot rows L1-L2, the spacing between pairs of adjacent dot portions 510 in the front-to-rear direction is the same. That is, the spacing between pairs of adjacent dot portions 510 is set so that dot row L1 = dot row L2. Therefore, the arrangement density of the multiple dot portions 510 in the outer dot area B (the number of dot portions 510 arranged per unit area in any of the dot rows L1-L2) is uniform from the boundary A toward the inside of the opening 51. This prevents the occurrence of a boundary in the arrangement density of the multiple dot portions 510 in the outer dot area B. Furthermore, because the boundary in the arrangement density of the multiple dot portions 510 itself is unlikely to occur, light transmittance is likely to be uniform throughout the entire outer dot area B. Therefore, when the backlight is turned on (when the light source unit 8 is turned on), the user is less likely to notice differences in luminous intensity.

[0049] 5 , when viewed from the front side, the total area of ​​the dot portions 510 in the inner dot area C is 25% to 50% of the area of ​​the inner dot area C, which is 100%. Therefore, compared to when the total area of ​​the dot portions 510 is less than 25%, the openings 51 are less likely to be visible to the user when the backlight is off. Furthermore, compared to when the total area of ​​the dot portions 510 is more than 50%, the light transmittance of the openings 51 is less likely to decrease when the backlight is on.

[0050] As shown in Fig. 5 , when viewed from the front side, the major axis of the elliptical dot portion 510 extends in the left-right direction. Both left and right ends of the major axis abut the circumscribing circle E. The diameter of the circumscribing circle E is 1.5 mm or less. Therefore, compared to when the diameter of the circumscribing circle E (i.e., the length of the major axis of the dot portion 510) exceeds 1.5 mm, the dot portion 510 itself is less likely to be visible to the user when the backlight is off.

[0051] As shown in Fig. 4, when viewed from the front side, opening 51 extends in a strip shape in the front-to-rear direction (longitudinal direction). The left-to-right length of opening 51 is 3 mm or more. That is, the aspect ratio of opening 51 is (left-to-right length: front-to-rear length) = (exceeding 1:1). When the left-to-right length (opening width) of opening 51 is 3 mm or more, boundary A becomes more easily visible to the user when the backlight is off.

[0052] In this regard, according to the decorative sheet 1 of this embodiment, the plurality of dot portions 510 are arranged in an area where the blurring effect of the boundary A can be effectively exhibited (an area where the horizontal length of the opening 51 is 3 mm or more), so that the boundary A can be prevented from being seen by the user when the backlight is turned off.

[0053] As shown in Figure 6, the visible light transmittance of the intermediate layer 4 is 3% or more and 30% or less. Therefore, compared to when the visible light transmittance of the intermediate layer 4 is less than 3%, the visibility of the opening 51 when the backlight is turned on can be improved. Furthermore, compared to when the visible light transmittance of the intermediate layer 4 is more than 30%, the visibility of the opening 51 showing through the surface of the skin layer 3 when the backlight is turned off can be reduced. The method for measuring the visible light transmittance will be described below. First, in a dark room with no lighting, a LED light source (luminance 3000 cd / m ２ The sample is placed on the sample holder and the LED light source is turned on. Next, the luminous intensity of the incident light, I0, and the luminous intensity of the light that has passed through the sample, I, are measured using a color luminance meter (manufactured by Konica Minolta, Inc., model number CS-160) at a position 1000 mm away from the measurement point of the sample (a circular portion with a diameter of approximately 4 mm). Thereafter, the visible light transmittance is calculated from the measurement results using the formula: visible light transmittance τ (%) = (I / I0) × 100.

[0054] As shown in Fig. 1, the decorative sheet 1 of this embodiment is disposed on a door trim 9, which is an interior member of a vehicle. Therefore, by switching the backlight on and off, the design of the door trim 9 can be given a dual-faceted appearance.

[0055] The manufacturing method of the decorative sheet 1 includes an intermediate layer printing step and a design layer printing step. Therefore, compared to when the intermediate layer 4 is a coating, for example, the variation in the thickness of the intermediate layer 4 can be suppressed. Also, the thickness of the intermediate layer 4 can be prevented from becoming excessively thick. The design layer 5 has the same effect as the intermediate layer 4. Also, the positional deviation in the layer direction between the three layers (skin layer 3, intermediate layer 4, and design layer 5) can be suppressed.

[0056] Second Embodiment The difference between the decorative sheet of this embodiment and the decorative sheet of the first embodiment is that the dot portions have an isosceles triangle shape. Here, only this difference will be described. Figure 7 shows a partial surface view of the design layer of the decorative sheet of this embodiment. Note that parts corresponding to those in Figure 5 are designated by the same reference numerals.

[0057] 7, when viewed from the front side, the dot portions 510 are in the shape of an isosceles triangle extending in the left-right direction. In any dot row L1-L2, any pair of dot portions 510 adjacent in the front-to-rear direction are arranged so that the vertices or bases point in opposite directions. In other words, the multiple dot portions 510 are arranged in a staggered pattern.

[0058] The decorative sheet of this embodiment and the decorative sheet of the first embodiment have the same effects as those of the first embodiment in terms of the common configuration. As in the decorative sheet of this embodiment, the dot portions 510 may be shaped like an isosceles triangle. Furthermore, the dot portions 510 may be arranged in a staggered pattern.

[0059] Third Embodiment The decorative sheet of this embodiment differs from the decorative sheet of the first embodiment in that the arrangement density of the multiple dots in the outer dot area gradually decreases from the boundary toward the inside of the opening. Here, only this difference will be described. Figure 8 shows a partial surface view of the design layer of the decorative sheet of this embodiment. Note that parts corresponding to those in Figure 5 are designated by the same reference numerals.

[0060] As shown in Figure 8, when viewed from the front side, three dot rows L1 to L3 are arranged in the outer dot area B from the outer edge B1 (boundary A) to the inner edge B2. The three dot rows L1 to L3 are aligned in the left-right direction. Each of the dot rows L1 to L3 includes a plurality of dot portions 510 arranged in a straight line (dotted line). The dot rows L1 to L3 extend in the front-rear direction.

[0061] In the three dot rows L1 to L3, the spacing between adjacent pairs of dot portions 510 is set to gradually increase (become gradually wider). That is, the spacing between adjacent pairs of dot portions 510 is set to be narrower in the order of dot row L1 → dot row L2 → dot row L3. Therefore, the arrangement density of the multiple dot portions 510 in the outer dot area B gradually decreases (decreases gradually) from the boundary A toward the inside of the opening 51.

[0062] The decorative sheet of this embodiment and the decorative sheet of the first embodiment have similar effects in common configurations. Let us assume that the arrangement density of the multiple dot portions 510 in the three dot rows L1 to L3 changes rapidly from the boundary A toward the inside of the opening 51. In this case, when the backlight is turned off, the boundary (the boundary between the arrangement densities of the multiple dot portions 510) between adjacent dot rows (dot row L1 and dot row L2, and dot row L2 and dot row L3) becomes more easily visible to the user. In this regard, with the decorative sheet of this embodiment, the arrangement density of the multiple dot portions 510 in the three dot rows L1 to L3 gradually decreases from the boundary A toward the inside of the opening 51. This allows the boundary between adjacent dot rows L1 to L3 to be blurred.

[0063] Furthermore, the light transmittance differs between areas where the dots 510 are arranged at high and low densities. Therefore, in the three dot rows L1 to L3, if the arrangement density of the dots 510 changes suddenly from the boundary A toward the inside of the opening 51, the difference in light transmittance becomes large. Therefore, when the backlight is turned on, the user can easily visually recognize the difference in luminous intensity. In this regard, with the decorative sheet of this embodiment, the arrangement density of the dots 510 gradually decreases from the boundary A toward the inside of the opening 51 in the three dot rows L1 to L3. Therefore, the difference in light transmittance is small. Therefore, when the backlight is turned on, the user cannot easily visually recognize the difference in luminous intensity.

[0064] <Others> The decorative sheet according to the present disclosure has been described above. However, the decorative sheet according to the present disclosure is not limited to the above-described embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

[0065] (Configuration) There are no particular limitations on the shape of the surface of the dot portion 510. Figures 9(A) to 9(D) show surface views of the dot portion of the decorative sheet of other embodiments (No. 1) to (No. 4). Note that parts corresponding to those in Figure 5 are denoted by the same reference numerals.

[0066] As shown in Fig. 9A, the dot portion 510 may be a square. Of course, it may be another regular polygon (such as an equilateral triangle, a regular pentagon, or a regular hexagon). It may also be a rectangle, a parallelogram, or the like. In other words, the shape of the dot portion 510 may be isotropic or anisotropic.

[0067] As shown in Fig. 9(B) , the dot portion 510 may be diamond-shaped. When the dot portion 510 has anisotropy, as in the diamond-shaped dot portion 510, the direction of the long axis is not particularly limited. It may be the left-right direction, the front-back direction, or an oblique direction (a direction intersecting the left-right direction or the front-back direction). The outer edge of the dot portion 510 may be in contact with the circumscribed circle E at at least two points.

[0068] As shown in FIG. 9(C), the dot portion 510 may be a perfect circle. In this case, the outer edge of the dot portion 510 coincides with the circumscribing circle E. As shown in FIG. 9(D), multiple dot portions 510 may be connected to one another. Multiple connected dot portions 510 may be displayed as lines. Also, multiple lines may be overlapped to display hatching. The direction in which the multiple dot portions 510 are connected is not particularly limited. They may be connected in the left-right direction, the front-back direction, or an oblique direction. The areas of the multiple dot portions 510 may be the same or different.

[0069] The arrangement of the multiple dot portions 510 in the opening 51 is not particularly limited. They may be arranged regularly or irregularly. The multiple dot portions 510 may be arranged so that the density of the multiple dot portions 510 increases from dense to sparse from the boundary A toward the inside of the opening 51.

[0070] The extending direction of the dot rows L1 to L3 shown in Figures 5, 7, and 8 is not particularly limited. It may be left-right, front-back, or diagonal. The juxtaposition direction of the multiple dot rows L1 to L3 is not particularly limited. It may be left-right, front-back, or diagonal. In any of the dot rows L1 to L3, the spacing between a pair of adjacent dot portions 510 is not particularly limited. It may be equal or uneven.

[0071] The shape of the side surface of the dot portion 510 is not particularly limited. It may be a flat surface extending in the stacking direction, a convex surface bulging in the layer-adjacent direction, a concave surface recessed in the layer-adjacent direction, or a shape that combines at least two of these surface shapes.

[0072] There are no particular limitations on the shapes, positions, or numbers of the openings 51, dot portions 510, and shielding portions 50 in the design layer 5. There are no particular limitations on the light transmittance of the openings 51, dot portions 510, and shielding portions 50. It is sufficient that the relationship of high to low light transmittance is "openings 51 > dot portions 510 > shielding portions 50" in ascending order. Alternatively, it is sufficient that the relationship of high to low light transmittance is "openings 51 > dot portions 510 = shielding portions 50" in descending order.

[0073] The layer structure of each layer (skin layer 3, intermediate layer 4, design layer 5, and base layer 6) is not particularly limited. It may be a single-layer structure or a multi-layer structure. Another layer may be interposed between two adjacent layers in the front-to-back direction. Furthermore, another layer may be disposed on the front side of the skin layer 3.

[0074] There are no particular limitations on the area of ​​each layer when viewed from the front side. For example, when viewed from the front side, the intermediate layer 4 and the design layer 5 may be disposed on a portion of the skin layer 3. When viewed from the front side, the design layer 5 may be disposed on a portion of the intermediate layer 4. When viewed from the front side, the intermediate layer 4 may be disposed on a portion of the design layer 5.

[0075] The color of the design displayed on the skin layer 3 may be a single color or multiple colors. The color may be expressed on the surface of the skin layer 3 by one or more selected from each layer and the light source unit 8. The light transmittance and transparency of each layer (excluding the shielding unit 50 of the design layer 5) are not particularly limited. They may be colorless and transparent, colored and transparent, translucent, etc. The color (hue, saturation, brightness) of each layer and the light source 80 is not particularly limited. The skin layer 3 does not need to have a grained portion 31. The surface of the skin layer 3 may be, for example, a smooth surface.

[0076] The positions and number of light sources 80 in the light source unit 8 are not particularly limited. A single light source 80 may include multiple LEDs. In this case, the colors of the multiple LEDs may be different. For example, if a single light source 80 includes three LEDs of red, green, and blue, it can emit white light in addition to red, green, and blue.

[0077] There are no particular limitations on the brightness of the light source 80. There are no particular limitations on the type, number, or location of the light source 80. The light source 80 may be an organic EL sheet, an inorganic EL sheet, a phosphorescent sheet, or the like. Furthermore, the light source unit 8 may include the light source 80 and a light guide plate (e.g., an acrylic plate).

[0078] The type of interior member on which the decorative sheet 1 is to be disposed is not particularly limited. Examples include door trim 9, seats, armrests, floors, ceilings, instrument panels, glove boxes, steering wheels, center consoles, and cash registers. The surface of the interior member (the surface of the skin layer 3) may be flat or curved. The orientation of the interior member (the orientation of the front and back directions of the decorative sheet 1) is not particularly limited. That is, the front and back direction may be vertical, horizontal, or a direction intersecting the vertical and horizontal directions. The decorative sheet 1 may also be disposed in interior members of transportation equipment other than vehicles (such as motorcycles, ships, and aircraft) and buildings (such as buildings and houses). The decorative sheet 1 may also be disposed in exterior members (such as the exterior walls of transportation equipment and buildings).

[0079] (Regarding Materials) The material of the skin layer 3 is not particularly limited. Examples include synthetic leather, resin, elastomer, nonwoven fabric, and various fabrics (woven fabrics, knitted fabrics, etc.). Specific examples of synthetic leather, resin, and elastomer include acrylic, polyethylene terephthalate, polycarbonate, polyvinyl chloride, silicone, epoxy, polyurethane, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, and dynamically crosslinked thermoplastic elastomer. Examples of nonwoven fabric and various fabrics include polyester, polypropylene, nylon, and cotton. The skin layer 3 may contain a colorant (such as colored polyethylene), a light diffusing agent (such as silicone, acrylic, or titanium oxide), or a light absorbing agent (such as titanium black or carbon black).

[0080] There are no particular limitations on the material of the intermediate layer 4. Examples include resins and elastomers such as acrylic, polyethylene terephthalate, polycarbonate, polyvinyl chloride, silicone, polyester, epoxy, polyurethane, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, and dynamically crosslinked thermoplastic elastomer. The intermediate layer 4 may contain the aforementioned colorant, light diffusing agent, and light absorbing agent.

[0081] The material of the design layer 5 (shielding portion 50, dot portion 510) is not particularly limited. Examples include resins and elastomers such as acrylic, polyethylene terephthalate, polycarbonate, polyvinyl chloride, silicone, polyester, epoxy, polyurethane, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, and dynamically crosslinked thermoplastic elastomer. The design layer 5 may contain the aforementioned colorant, light diffusing agent, and light absorbing agent.

[0082] The opening 51 may be hollow (space) or solid. Specifically, the portion of the opening 51 where the dot portions 510 are not arranged (no-dot portion) may be hollow or solid. When the no-dot portion is solid, the material of the no-dot portion may be the same as the material of the design layer 5 described above (resin, elastomer). Of course, the no-dot portion may contain the colorant, light diffusing agent, and light absorbing agent described above. When the no-dot portion is solid, it is sufficient that the relationship of high to low light transmittance is "no-dot portion > dot portion 510 > shielding portion 50" in ascending order. Alternatively, it is sufficient that the relationship of high to low light transmittance is "no-dot portion > dot portion 510 = shielding portion 50" in descending order.

[0083] The material of the base layer 6 is not particularly limited. Examples include elastomers and resins. Specific examples include elastomers such as styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, dynamically crosslinked thermoplastic elastomers, styrene-based thermoplastic elastomers, and olefin-based thermoplastic elastomers. Other examples include foams such as polyurethane foam. Other examples include resins such as acrylic, polyethylene terephthalate, polycarbonate, polyvinyl chloride, silicone, polyester, and epoxy.

[0084] When the intermediate layer 4 and the base layer 6 have light diffusibility, the method for imparting the light diffusibility is not particularly limited. For example, a light diffusing agent (such as silicone, acrylic, or titanium oxide) having a refractive index different from that of a transparent base material may be dispersed in the base material.

[0085] The method for laminating each layer is not particularly limited. Screen printing (such as silk screen printing), gravure printing, inkjet printing, flexographic printing, etc. may be used. Furthermore, each layer may be laminated by adhesion, pressure bonding, pasting, vapor deposition, welding, painting, etc. Another film-like layer (such as the design layer 5) may be adhered to the back surface of any layer (such as the intermediate layer 4). Furthermore, another layer (such as the intermediate layer 4) may be painted on the back surface of any layer (such as the skin layer 3).

[0086] 1: Decorative sheet, 3: Skin layer, 31: Grain portion, 4: Intermediate layer, 5: Design layer, 50: Shielding portion, 51: Opening, 510: Dot portion, 6: Base layer, 8: Light source portion, 80: Light source, 9: Door trim (interior member), A: Boundary, B: Outer dot area, B1: Outer edge, B2: Inner edge, C: Inner dot area, E: Circumscribed circle, L1 to L3: Dot row

Claims

1. A decorative sheet comprising: a surface layer having light transparency; an intermediate layer having light transparency and disposed on the back side of the surface layer; a design layer disposed on the back side of the intermediate layer; and a base layer having light transparency and disposed on the back side of the design layer, wherein, as viewed from the front side, the design layer has a shielding portion and an opening disposed adjacent to the shielding portion via a boundary; as viewed from the front side, a plurality of dot portions are disposed within the opening, the plurality of dot portions are disposed so as to become more sparse from the boundary toward the inside of the opening, the opening has a higher light transparency than the shielding portion and the dot portion, and the dot portion has the same light transparency as the shielding portion or a higher light transparency than the shielding portion.

2. The decorative sheet as described in claim 1, wherein, when viewed from the front side, the opening is partitioned into an outer dot area arranged adjacent to the boundary and an inner dot area arranged adjacent to the outer dot area, and a plurality of the dot portions are densely arranged in the outer dot area relative to the inner dot area.

3. A decorative sheet as described in claim 2, wherein the direction perpendicular to the extension direction of the boundary is the width direction, and of the two ends of the outer dot area in the width direction, the end closest to the shielding portion is the outer end and the end closest to the opening is the inner end, the outer end is the boundary, and the entire width direction length of the opening is 100%, and the inner end is located within 33% of the boundary in the width direction.

4. The decorative sheet according to claim 2, wherein the arrangement density of the dot portions in the outer dot area gradually decreases from the boundary toward the inside of the opening when viewed from the front side.

5. The decorative sheet according to claim 2, wherein the dots in the outer dot area are arranged at a uniform density when viewed from the front side.

6. The decorative sheet according to claim 2, wherein the total area of ​​the dot portions in the inner dot area is 25% or more and 50% or less of the area of ​​the inner dot area, when viewed from the front side, of 100% of the area of ​​the inner dot area.

7. The decorative sheet according to claim 1, wherein the diameter of the circumscribing circle of the dot portion when viewed from the front side is 1.5 mm or less.

8. The decorative sheet according to claim 1, wherein the opening is strip-shaped when viewed from the front side, and the short-side length of the opening is 3 mm or more.

9. The decorative sheet according to claim 1, wherein the visible light transmittance of the intermediate layer is 3% or more and 30% or less.

10. The decorative sheet according to claim 1, which is disposed on an interior member of a vehicle.

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