Shaping film, laminate, laminate with light guide layer, and lighting device

Abstract

The present invention reduces luminance unevenness. This shaping film is an optical shaping film having a main surface, wherein, on the main surface, a plurality of recesses having an inclined surface for totally reflecting light is aligned in a formation direction with a first period P1, and a plurality of protrusions is aligned in the formation direction at with a second period P2. Where the maximum depth of the recesses is Dx and the maximum height of the protrusions is Hx, Hx / Dx is 4% or less.

Description

Shape-transferring film, laminate, laminate with light-guiding layer, and lighting device

[0001] The present invention relates to a shaped film, a laminate, a laminate with a light guide layer, and a lighting device.

[0002] For example, Patent Document 1 discloses a transparent substrate having a plurality of recesses or protrusions formed on one of its main surfaces.

[0003] International Publication No. 2019 / 102959

[0004] However, when light is incident on the inside of a shape-imparting film such as the transparent substrate described in Patent Document 1, uneven brightness may occur in the light extracted from the shape-imparting film.

[0005] An object of the present invention is to reduce brightness unevenness.

[0006] A shaped film according to one embodiment of the present invention is an optical shaped film having a main surface, in which a plurality of recesses having inclined surfaces that totally reflect light are arranged in a formation direction at a first period P1, and a plurality of convex portions are arranged in the formation direction at a second period P2, and when the maximum depth of the recesses is Dx and the maximum height of the convex portions is Hx, Hx / Dx is 4% or less.

[0007] According to the present invention, it is possible to reduce brightness unevenness.

[0008] 10 is a schematic plan view showing a first example of a lighting device including a shaped-transfer film according to an embodiment. A schematic cross-sectional view taken along line II-II in FIG. 1. A schematic cross-sectional view of a shaped-transfer film corresponding to line III-III in FIG. 1. A schematic cross-sectional view of a mold for explaining a method for manufacturing a shaped-transfer film. A schematic cross-sectional view of a mold used for manufacturing a shaped-transfer film. A schematic cross-sectional view of a cavity provided in a shaped-transfer film according to an embodiment. A schematic plan view showing a first example of a cavity provided in a shaped-transfer film according to an embodiment. A schematic plan view showing a second example of a cavity provided in a shaped-transfer film according to an embodiment. A schematic plan view of a shaped-transfer film according to another embodiment. A diagram explaining an example of an evaluation direction of luminance unevenness. A diagram showing the luminance distribution of an image of a shaped-transfer film obtained by luminance unevenness evaluation. A diagram showing the result of removing luminance attenuation components according to the distance from the LED light source from the luminance distribution of FIG. 10. A diagram showing the maximum height of a convex portion and the maximum depth of a concave portion. A diagram showing an image of light emitted from a shaped-transfer film according to Example 1 obtained by luminance unevenness evaluation. A diagram showing an image of light emitted from a shaped-transfer film according to Comparative Example 1 obtained by luminance unevenness evaluation. 10 is a diagram showing the relationship between the ratio of the maximum height of the convex portion to the maximum depth of the concave portion and the effective value. FIG. 11 is a schematic cross-sectional view showing a second example of a lighting device including a shaped film according to an embodiment.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same components are given the same reference numerals, and duplicated descriptions will be omitted as appropriate.

[0010] The following embodiments are illustrative of a shaped film, a laminate, a laminate with a light guide layer, and a lighting device for embodying the technical concept of the present invention, and are not intended to limit the present invention to the following embodiments. The dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only, and are not intended to limit the scope of the present invention, unless otherwise specified. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0011] In the drawings shown below, directions are expressed using a Cartesian coordinate system having an X-axis, a Y-axis, and a Z-axis. The X-axis, the Y-axis, and the Z-axis are approximately perpendicular to one another. The direction in which the arrow representing the X-axis points is referred to as the +X direction or +X side, and the direction opposite to the +X direction is referred to as the -X direction or -X side. The direction in which the arrow representing the Y-axis points is referred to as the +Y direction or +Y side, and the direction opposite to the +Y direction is referred to as the -Y direction or -Y side. The direction in which the arrow representing the Z-axis points is referred to as the +Z direction or +Z side, and the direction opposite to the +Z direction is referred to as the -Z direction or -Z side.

[0012] The X direction along the X axis corresponds to the forming direction in which the plurality of recesses provided in the shaped film according to the embodiment are arranged at a first period P1. In the description of the embodiment, the above-mentioned forming direction is referred to as the forming direction X. The Z direction along the Z axis indicates the direction along the normal to the main surface of the shaped film according to the embodiment. In this specification, "planar view" refers to viewing an object from the +Z direction. The +Z direction is referred to as "up" and the -Z direction is referred to as "down." However, these directional expressions merely represent relative positional relationships for the purpose of explanation and do not limit the directions of the embodiment.

[0013] In this specification and claims, "substantially parallel" means that the absolute value of the angular deviation from the parallel state is between 0 and 10 degrees. Furthermore, "substantially perpendicular" means that the absolute value of the angular deviation from the perpendicular state is between 0 and 10 degrees. "Arranged" does not necessarily mean direct contact, but also includes indirect arrangement, for example, via another member. Furthermore, in this specification, "thickness" refers to the length of the object in the Z direction. Furthermore, in this specification, cross-sectional views may be shown as end views showing only the cross section.

[0014] [Embodiment] <Overall configuration of lighting device including shaped-transfer film according to embodiment> The overall configuration of a lighting device including a shaped-transfer film according to an embodiment will be described with reference to Figures 1 to 5. Figure 1 is a schematic plan view showing a first example of a lighting device 100 including a shaped-transfer film 62 according to an embodiment. Figure 2 is a schematic cross-sectional view taken along line II-II in Figure 1. Figure 3 is a schematic cross-sectional view showing an example of a shaped-transfer film 62 corresponding to line III-III in Figure 1. Figure 4 is a schematic cross-sectional view showing an example of a method for manufacturing the shaped-transfer film 62. Figure 5 is a schematic cross-sectional view explaining an example of a mold used in manufacturing the shaped-transfer film 62.

[0015] 1 and 2, the lighting device 100 includes a laminate 80 with a light guide layer, and a light source LS disposed near an end surface 81 of the laminate 80 with a light guide layer. The light source LS shown in Fig. 2 is disposed at a position where it can emit light toward the end surface 81 of the laminate 80 with a light guide layer. In the example shown in Fig. 2, part of the light Lr emitted from the light source LS is indicated by a dashed arrow.

[0016] The laminate 80 with a light guide layer includes a light guide layer 10, a laminate 70, and a first adhesive layer 52. The first adhesive layer 52 is disposed between the light guide layer 10 and the laminate 70, and is a layer that bonds the light guide layer 10 and the laminate 70 together. The laminate 70 includes a substrate 30 and a direction changing layer 60. The direction changing layer 60 includes a shaped film 62 and a second adhesive layer 54. The second adhesive layer 54 is disposed between the shaped film 62 and the substrate 30, and is a layer that bonds the shaped film 62 and the substrate 30 together. The substrate 30 is disposed opposite a main surface 621 of the shaped film 62. The light guide layer 10 is disposed opposite the shaped film 62. The shaped film 62 is a film manufactured without cutting the material.

[0017] A plurality of cavities 64 are provided inside the direction-changing layer 60. Each of the plurality of cavities 64 has a first inclined surface ISa (corresponding to the inclined surface of the present invention) and a second inclined surface ISb arranged on the opposite side of the first inclined surface ISa in the Y direction. For example, air is present inside the cavity 64. A plurality of recesses 622 are provided on the main surface 621 of the shaped film 62. The open portions of each of the plurality of recesses 622 are blocked by the substrate 30 arranged on the main surface 621 via the second adhesive layer 54, thereby forming the cavity 64. The cavity 64 may also be referred to as an internal space or an air cavity.

[0018] The lighting device 100 is used, for example, with the light guide layer-equipped laminate 80 disposed on an adherend such as glass, a window, a wall, a floor, or a ceiling. Light Lr emitted from the light source LS of the lighting device 100 enters the inside of the light guide layer-equipped laminate 80 from an end surface 81 and is guided inside the light guide layer-equipped laminate 80. A portion of the light Lr guided inside the light guide layer-equipped laminate 80 is reflected toward the −Z side by either the first inclined surface ISa or the second inclined surface ISb of the cavity 64, passes through the exit surface 82 of the light guide layer-equipped laminate 80, and is emitted in the −Z direction intersecting with the main surface 621 of the shaping film 62. The lighting device 100 can illuminate an indoor space in which the light guide layer-equipped laminate 80 is disposed, using light Lr emitted from almost the entire exit surface 82 of the light guide layer-equipped laminate 80.

[0019] The shaped film 62 shown in FIG. 3 is an optical shaped film having a main surface 621. On the main surface 621, a plurality of recesses 622 having a first inclined surface ISa that totally reflects light are arranged in the forming direction X at a first period P1, and a plurality of protrusions 65 are arranged in the forming direction X at a second period P2. The protrusions 65 are preferably flat, but as described below, they are uneven due to the molding process of the shaped film 62. The maximum depth of the recesses 622 is greater than the maximum height of the protrusions 65. In the example shown in FIG. 3, the maximum height Hx of the protrusions 65 is 0.40 μm or less. Details of the definition of the maximum height Hx of the protrusions 65 will be described separately with reference to FIG. 14.

[0020] The first period P1 corresponds to the center-to-center distance between adjacent recesses 622 in the forming direction X. In the example shown in Fig. 3 , the center-to-center distance is the distance in the forming direction X between the center C11 and the center C12 of adjacent recesses 622 in the forming direction X. From another perspective, the first period P1 may be the distance between the lowest positions of adjacent recesses 622 in the forming direction X.

[0021] The second period P2 corresponds to the center-to-center distance between adjacent convex portions 65 in the forming direction X. In the example shown in Fig. 3 , the center-to-center distance is the distance in the forming direction X between the centers C21 and C22 of adjacent convex portions 65 in the forming direction X. From another perspective, the second period P2 may be the distance between the highest positions of adjacent convex portions 65 in the forming direction X.

[0022] Here, in a shaped film having a plurality of recesses, when the shaped film is applied to a lighting device, etc., brightness unevenness may occur in the light extracted from the lighting device through the shaped film. Below, the cause of this brightness unevenness will be described together with an example of a manufacturing method of the shaped film.

[0023] The shaped film having a plurality of recesses is manufactured by molding a resin material using a mold. In the manufacturing method of the shaped film, first, a roll member made of a metal material or the like and serving as a material for the mold is prepared.

[0024] Next, the outer peripheral surface of the roll member is mirror-finished by cutting, grinding, or the like, to form a roll-shaped mold having a plurality of projections on the outer peripheral surface.

[0025] Next, a plurality of recesses are formed on the outer peripheral surface of the roll-shaped mold by cutting or grinding, etc. In forming the recesses, a different machining tool from that used for mirror finishing is used, and the outer peripheral surface of the roll-shaped mold after mirror finishing is continuously or intermittently cut or ground by FTS (Fast tool servo) drive. This forms a plurality of recesses on the outer peripheral surface of the mold.

[0026] Next, a sheet-like resin substrate for the intermediate transfer member, made of a resin material or the like, is wound around a portion of a roll-shaped mold, an active energy ray-curable resin is disposed between the resin substrate for the intermediate transfer member and the roll-shaped mold, and active energy rays are irradiated to cure the active energy ray-curable resin. By curing the active energy ray-curable resin, an intermediate transfer member composed of the resin substrate for the intermediate transfer member and the active energy ray-curable resin is obtained. An inverted shape of either a plurality of recesses or protrusions on the mold is formed on the surface of the intermediate transfer member. When recesses are formed on the mold, the inverted shape formed on the intermediate transfer member will be protrusions. On the other hand, when protrusions are formed on the mold, the inverted shape formed on the intermediate transfer member will be recesses.

[0027] Next, the sheet-like intermediate transfer member on which the reversed shape is formed is arranged on the outer circumferential surface of a roller member other than the roll-like mold so as to be wound around the roller member, thereby forming a transfer roller.

[0028] Next, a sheet-like resin substrate for a shape-transfer film made of a resin material or the like is wound around a part of the transfer roller, a releasable active energy ray-curable resin is placed between the transfer roller and the resin substrate for the shape-transfer film, and the active energy ray is irradiated to cure the active energy ray-curable resin. By curing the active energy ray-curable resin, a shape-transfer film composed of the resin substrate for the shape-transfer film and the active energy ray-curable resin is obtained. The shape-transfer film is peeled off from the transfer roller.

[0029] By the above process, the shape of either the plurality of recesses or the plurality of protrusions on the transfer roller is reversed, and either the plurality of recesses or the plurality of protrusions formed on the roll-shaped mold are transferred to the shape-transfer film via the intermediate transfer member.

[0030] Here, even when the outer peripheral surface of the roll-shaped die is mirror-finished, convex portions depending on the performance of the processing equipment may remain as processing marks, etc., as shown in Figures 4 and 5. Figure 4 shows how mirror-finishing is performed on the outer peripheral surface of a roll-shaped die 300 that rotates around a rotation axis parallel to the X axis while feeding the processing tool 200 at a predetermined feed rate in the +X direction. Note that Figure 4 shows an enlarged view of the vicinity of the outer peripheral surface of the die 300.

[0031] Even if the tip 200a of the machining tool 200 that comes into contact with the die 300 is manufactured to be sharp, it will have a certain degree of rounded shape microscopically. Therefore, on the outer peripheral surface of the roll-shaped die 300 after mirror finishing, multiple convex portions corresponding to the shape of the tip 200a of the machining tool 200 remain, aligned in the forming direction X at a second period P2 corresponding to the feed amount of the machining tool 200. In the example shown in Figure 4, multiple die convex portions 302 corresponding to the shape of the tip 200a of the machining tool 200 remain on the outer peripheral surface of the die 300.

[0032] On the other hand, Figure 5 shows how a plurality of mold recesses 301 corresponding to a plurality of recesses to be provided in the shaped film are processed on the outer peripheral surface of a roll-shaped mold 300 rotating around a rotation axis parallel to the X axis. Figure 5 also shows an enlarged view of the vicinity of the outer peripheral surface of the mold 300. A plurality of mold recesses 301 are formed on the outer peripheral surface of the roll-shaped mold 300 in the forming direction X so as to overlap a plurality of mold protrusions 302 at a period substantially the same as the first period P1 of the plurality of recesses to be provided in the shaped film.

[0033] By manufacturing a shaped film using a mold 300 formed by superimposing multiple mold recesses 301 and multiple mold protrusions 302, shapes corresponding to the multiple mold recesses 301 and multiple mold protrusions 302 are superimposed on the shaped film. However, for example, if the relative position of the mold recesses 301 with respect to the mold protrusions 302 changes depending on the position within the main surface of the shaped film, the reflection area of ​​the mold protrusions 302 changes depending on the relative position of the mold recesses 301 with respect to the mold protrusions 302. This change in reflection area causes the brightness of the light extracted from the main surface of the shaped film to change depending on the position within the main surface of the shaped film, which can result in brightness unevenness in the light extracted from the main surface of the shaped film. Such brightness unevenness reduces the quality of lighting devices equipped with shaped films.

[0034] In the shaped film 62 according to this embodiment, when the maximum height of the recessed portions 622 is Hx and the maximum depth of the protruding portions 65 is Dx, the Hx / Dx ratio is 4% or less. By setting the Hx / Dx ratio within this range, the effective luminance of light extracted from the main surface 621 when light is incident on the inside of the shaped film 62 is 0.2% or less. This allows for reduced luminance unevenness in this embodiment. The upper limit of Hx / Dx may be 3% or less, 2.5% or less, or 2% or less. The lower limit of Hx / Dx may be greater than 0%, and may be 0.1% or more, 0.2% or more, 0.5% or more, or 1% or more. Details of the effective value will be described later with reference to FIGS. 10 and 11.

[0035] In the shaped film 62 shown in FIG. 3 , the maximum height Hx of the convex portions 65 is 0.40 μm or less. This allows brightness unevenness to be reduced regardless of the first period P1 of the plurality of concave portions 622 and the second period P2 of the plurality of convex portions 65. The upper limit of the maximum height Hx of the convex portions 65 may be 0.35 μm or less, 0.30 μm or less, 0.25 μm or less, 0.20 μm or less, 0.15 μm or less, or 0.12 μm or less. The lower limit of the maximum height Hx of the convex portions 65 may be 0.01 μm or more, 0.02 μm or more, 0.03 μm or more, 0.05 μm or more, 0.08 μm or more, or 0.09 μm or more. The maximum depth Dx of the concave portions 622 is, for example, 2 to 20 μm. The upper limit of the maximum depth Dx may be 15 μm or less, 12 μm or less. The lower limit of the maximum depth Dx may be 3 μm or more, 4 μm or more, or 5 μm or more. By increasing the maximum depth Dx, Hx / Dx can be reduced, and the influence of the maximum height Hx of the recess 622 can be reduced.

[0036] 1, a plurality of recesses 622 are further arranged in the Y direction intersecting with the forming direction X on the main surface 621 of the shaped film 62. This makes it possible to reduce the uneven brightness of the light extracted from the main surface 621 of the shaped film 62 even in the shaped film 62 extending in a two-dimensional direction.

[0037] 2, the laminate 70 includes a shaped film 62 and a substrate 30 disposed opposite a main surface 621 of the shaped film 62. This makes it possible to reduce uneven brightness of light extracted from the laminate 70 through the shaped film 62.

[0038] Alternatively, the light guide layer may be prepared separately from the laminate. The laminate 80 with a light guide layer includes the laminate 70 and the light guide layer 10 disposed opposite the shaping film 62. This reduces uneven brightness of the light extracted from the laminate 80 with a light guide layer via the shaping film 62. The light guide layer 10 may be disposed opposite the substrate 30.

[0039] The lighting device 100 includes a laminate 80 with a light guide layer and a light source LS disposed near an end surface 81 of the laminate 80 with a light guide layer. This reduces unevenness in brightness of the light extracted from the lighting device 100 via the shaping film 62. However, the lighting device can also be formed from the laminate 80 and the light source LS.

[0040] In the lighting device 100, light Lr emitted from the light source LS enters the inside of the laminate with a light guide layer 80 from the end face 81 and the end face 81 of the laminate with a light guide layer 80, is guided inside the laminate with a light guide layer 80, and then exits from the laminate with a light guide layer 80 through the exit surface 82. This makes it possible to provide a surface-illumination type lighting device 100 that can illuminate with light Lr extracted from almost the entire exit surface 82. The light source LS may be disposed on at least one of the end face 81 and the exit surface 82.

[0041] <Details of the Configuration of the Illumination Device 100> The following describes the details of the configuration of the illumination device 100. The illumination device 100 has a light distribution control structure having a plurality of cavities 64. The first inclined surface ISa in each of the plurality of cavities 64 directs a portion of the light Lr guided within the laminate 80 with a light-guiding layer toward the exit surface 82 by total internal reflection (TIR). Note that when the light Lr passes through an interface, it may be refracted according to the refractive index of the material that constitutes the interface.

[0042] The laminate 80 with a light guide layer is configured, by the light distribution control structure, to emit light Lr having a desired light distribution from the exit surface 82. The light distribution can be controlled by adjusting, for example, the cross-sectional shape, planar shape, size, arrangement density, distribution, etc. of the cavities 64.

[0043] The laminate 80 with a light guide layer has a visible light transmittance of 60% or more and a haze value of less than 30%. The visible light transmittance is preferably 70% or more, and more preferably 80% or more. The haze value is preferably less than 10%, and more preferably 5% or less. Since the laminate 80 with a light guide layer has a high visible light transmittance and a low haze value, objects (displays) can be seen through the laminate 80 with a light guide layer. Visible light is light with a wavelength of 380 nm or more and 780 nm or less. The visible light transmittance and haze value can be measured using a haze meter (manufactured by Murakami Color Research Laboratory: product name HM-150) or the like.

[0044] The ratio of the area of ​​the plurality of cavities 64 to the area of ​​the light guide layer 10 (occupancy rate) is preferably 1% or more and 80% or less when the light guide layer 10 is viewed from the normal direction of the light exit surface 82. The upper limit of the occupation rate is more preferably 50% or less, and even more preferably 45% or less, and in order to obtain at least one of high transmittance and low haze value, it is preferably 30% or less, more preferably 10% or less, and even more preferably 5% or less.

[0045] For example, when the cavity occupancy rate is 50%, a haze value of 30% can be obtained. The cavity occupancy rate may be uniform, or may increase with increasing distance from the light source LS so that brightness does not decrease even when the distance from the light source LS increases. For mass production using a roll-to-roll method or a roll-to-sheet method, it is preferable that the cavity occupancy rate be uniform.

[0046] In the laminate 80 with a light guide layer, the light guide layer 10 and the shaped film 62 are bonded together by a first adhesive layer 52. The substrate 30 and the shaped film 62 are bonded together by a second adhesive layer 54 that constitutes the shaped film 62 and the direction changing layer 60. The light guide layer 10 and the substrate 30 may be transparent substrates or films.

[0047] 1, the cavities 64 are discretely arranged in the X and Y directions of the light guide layer 10. However, the discrete arrangement of the cavities 64 may be appropriately set depending on the shape of the light guide layer 10, the desired light distribution, etc.

[0048] 1, a plurality of cavities 64 having substantially the same shape and curved surfaces convex in the same direction are discretely and periodically arranged over the entire region in the X and Y directions. In this case, the first period P1 is preferably, for example, 10 μm or more and 500 μm or less, and the pitch Py is preferably, for example, 10 μm or more and 500 μm or less. In the example shown in FIG. 1, the laminate 80 with a light guide layer further includes cavities 64 that are shifted from one another by half the first period P1 in the X direction and half the pitch Py in the Y direction.

[0049] The light source LS is, for example, an LED (Light Emitting Diode) device. A plurality of LED devices are arranged in a line in the X direction. There are no particular limitations on the number and arrangement of the LEDs. Note that the light source LS is not limited to an LED device and may be a halogen lamp or the like.

[0050] The detailed configuration of the cavity 64 will be described with reference to Figures 6 to 8. Figure 6 is a schematic cross-sectional view showing an example of the cavity 64. Figure 7 is a schematic plan view showing a first example of the cavity 64. Figure 8 is a schematic plan view showing a second example of the cavity 64.

[0051] The cross-sectional shape of the cavity 64 shown in Fig. 6 is substantially triangular. However, the cross-sectional shape of the cavity 64 is not limited to a substantially triangular shape and may be a substantially trapezoid, etc. In the example shown in Fig. 6, the inclination angle θa of the first inclined surface ISa is larger than the inclination angle θb of the second inclined surface ISb.

[0052] The inclination angle θa of the first inclined surface ISa on the light source LS side is, for example, 10° or more and 70° or less. If the inclination angle θa is smaller than 10°, the controllability of the light distribution may decrease, and the light extraction efficiency may also decrease. On the other hand, if the inclination angle θa exceeds 70°, it may become difficult to process the shaped film 62. By setting the inclination angle θa to 10° or more and 70° or less, the light extraction efficiency can be increased and the processing of the shaped film 62 can be made easier. The lower limit of the inclination angle θa may be 20° or more, 30° or more, or 40° or more. The upper limit of the inclination angle θa may be 60° or less, 50° or less.

[0053] The inclination angle θb of the second inclined surface ISb is, for example, 50° or more and 100° or less. If the inclination angle θb is less than 50°, stray light may be generated in an unintended direction. On the other hand, if the inclination angle θb exceeds 100°, it may become difficult to process the shaping film 62. By setting the inclination angle θba to 50° or more and 100° or less, the light extraction efficiency can be increased and the shaping film 62 can be easily processed.

[0054] 7 is a curved surface convex toward the light source LS in a plan view. Here, the light emitted from each of the plurality of LED devices constituting the light source LS has a spread in the Y direction. Therefore, the first inclined surface ISa acts uniformly on the light when the first inclined surface ISa has a curved surface convex toward the light source LS. Note that if a coupling optical system is provided between the light source LS and the end surface 81 of the laminate 80 with a light guide layer to allow highly parallel light (light with a small spread in the Y direction) to be incident, the first inclined surface ISa may be parallel to the X direction.

[0055] As shown in Figures 7 and 8, the length L of the cavity 64 is preferably 10 µm or more and 500 µm or less, and the width W is preferably 1 µm or more and 100 µm or less. The length L is preferably, for example, at least twice the width W. The height H is preferably 1 µm or more and 100 µm or less. Depending on the processing accuracy when forming the shaped film 62 including the recess 622 having the shape shown in Figure 7 in plan view, the recess 622 may have the shape shown in Figure 8 in plan view. Even in such a case, the shape of the cavity 64 in plan view can be specified by the length L and the width W.

[0056] The shaping film 62 can be manufactured using, for example, polymethyl methacrylate (PMMA). The total thickness of the shaping film 62 is, for example, 200 μm or less, 150 μm or less, with a lower limit of 20 μm or more. The visible light transmittance of the shaping film 62 is 60% or more, and the haze value is less than 30%. The visible light transmittance is preferably 70% or more, and more preferably 80% or more. The haze value is preferably less than 10%, and more preferably 5% or less. Visible light can be measured by the above-mentioned method.

[0057] The light guide layer 10 is formed of a known material with high transmittance to visible light. The light guide layer 10 is formed, for example, of an acrylic resin such as polymethyl methacrylate (PMMA), a polycarbonate (PC) resin, a cycloolefin resin, or glass (quartz glass, alkali-free glass, borosilicate glass, etc.). The refractive index nGP of the light guide layer 10 is, for example, 1.40 or more and 1.80 or less. Unless otherwise specified, the refractive index refers to the refractive index measured with an ellipsometer at a wavelength of 550 nm. The thickness of the light guide layer 10 can be appropriately set depending on the application. The thickness of the light guide layer 10 is, for example, 0.05 mm or more and 50 mm or less.

[0058] The thickness of the substrate 30 is, for example, 1 μm to 1000 μm, preferably 10 μm to 100 μm, and more preferably 20 μm to 80 μm. The refractive index of the substrate 30 is independently preferably 1.40 to 1.70, and more preferably 1.43 to 1.65.

[0059] The thicknesses of the first adhesive layer 52 and the second adhesive layer 54 are each independently, for example, from 0.1 μm to 100 μm, preferably from 0.3 μm to 100 μm, and more preferably from 0.5 μm to 50 μm. The refractive indexes of the first adhesive layer 52 and the second adhesive layer 54 are each independently preferably from 1.42 to 1.60, and more preferably from 1.47 to 1.58. The refractive indexes of the first adhesive layer 52 and the second adhesive layer 54 are preferably close to the refractive index of the light guide layer 10 or the shaping film 62 to which they are in contact, and the absolute value of the difference in refractive index is preferably 0.2 or less.

[0060] The second adhesive layer 54 can preferably be bonded without filling the recesses 622 of the shaped film 62. Suitable adhesives for forming the second adhesive layer 54 include those described in International Application PCT / JP2021 / 006452, International Application PCT / JP2021 / 006453, or Japanese Patent Application No. 2021-025496 filed by the present applicant. The entire disclosures of these applications are incorporated herein by reference. In particular, the polyester-based adhesive described in Japanese Patent Application No. 2021-025496 is preferred.

[0061] <Evaluation of Brightness Unevenness> (Method of Evaluating Brightness Unevenness) Next, a method of evaluating brightness unevenness in a shaped film 62 will be described with reference to FIGS. 9 to 12. FIG. 9 is a schematic plan view of a shaped film according to another embodiment. FIG. 10 is a diagram illustrating a method of evaluating brightness unevenness. FIG. 11 is a diagram showing an example of a brightness distribution in an image of a shaped film obtained by brightness unevenness evaluation. FIG. 12 is a diagram showing an example of the result of removing the brightness attenuation component according to the distance from the LED light source 500 from the brightness distribution of FIG. 11. FIG. 9 is an example in which the recesses 622 of the shaped film 62 have a longitudinal direction, similar to FIG. 1. FIG. 9 is an example in which the longitudinal direction of the recesses 622 is different from that of FIG. 1. In FIG. 1, the longitudinal direction of the recesses 622 coincides with the formation direction. In FIG. 9, the direction perpendicular to the longitudinal direction of the recesses 622 in a plan view coincides with the formation direction.

[0062] In the brightness unevenness evaluation method shown in FIG. 10 , first, a substrate 30 (PMMA: 40 μm) was bonded to the main surface 621 of the shaped film 62 shown in FIG. 9 via a second adhesive layer 54 (polyester adhesive). Then, the surface opposite the main surface 621 of the shaped film 62 was bonded to a light-transmitting substrate 401. For the light-transmitting substrate 401, Acrylite EX manufactured by Mitsubishi Chemical Corporation, measuring 145 mm in length, 1000 mm in width, and 5 mm in thickness, was used. CS9862 manufactured by Nitto Denko Corporation was used as the adhesive. After bonding the shaped film 62 to the light-transmitting substrate 401, the shaped film 62 was autoclaved at a temperature of 50° C., a pressure of 0.5 MPa, and for 15 minutes to produce an evaluation sample 400.

[0063] The following were used for the shaped film 62 in Examples 1, 2, 6, and Comparative Example 1. Thickness: 130 μm Pitch of first period (x direction in FIG. 9): 150 μm, pitch in the direction perpendicular to the first period (Y direction in FIG. 9): 143 μm Inclination angle θa of first inclined surface ISa: 49° Area ratio of multiple recesses 622 to the area of ​​shaped film 62: less than 5% Shape of recess 622: Shape in FIG. 8 W ​​20 μm L 80 μm Maximum height Hx, maximum depth Dx: As shown in Table 1

[0064] The shaped films 62 of Examples 3, 4, 5, and Comparative Example 2 had a pitch of 259 μm in the first period (X direction in FIG. 9 ), a pitch of 155 μm in the direction perpendicular to the first period (Y direction in FIG. 9 ), and an area ratio of the plurality of recesses 622 to the area of ​​the shaped film 62 of less than 5%. Other conditions were the same as those of the shaped films 62 of Examples 1, 2, 6, and Comparative Example 1.

[0065] Next, light from the LED light source 500 was incident on the inside of the evaluation sample 400 through the end portion 402 of the evaluation sample 400. A line flat bar manufactured by FKK Corporation was used as the LED light source 500. The LED light source 500 was driven at a driving current of 24 V and a driving current of 0.2 A.

[0066] The luminance of light guided through the interior of the evaluation sample 400 and emitted from almost the entire main surface 621 of the shaped film 62 was measured using a two-dimensional spectroradiometer 600. An SR-5000 manufactured by Topcon Corporation was used as the two-dimensional spectroradiometer 600. The distance Tz from the main surface 621 to the two-dimensional spectroradiometer 600 was set to 3.0 m. In the image obtained by the two-dimensional spectroradiometer 600, a linear image region corresponding to a region along the formation direction X at a position a distance Tx away from the LED light source 500 in the X direction was extracted. The distance Tx was set to a range of 450 mm or more and 550 mm or less.

[0067] Fig. 11 shows the luminance distribution of a linear image region in an image obtained by the two-dimensional spectroradiometer 600. In Fig. 11, the horizontal axis represents the distance Tx from the LED light source 500 in the X direction. The vertical axis represents the luminance value. In Fig. 11, the luminance value decreases as the distance Tx from the LED light source 500 increases, because the amount of light reaching the image from the LED light source 500 decreases.

[0068] In the evaluation, the measurement data in Fig. 11 was approximated by a cubic function, and the luminance value according to the cubic function was subtracted from the measurement data. In this way, the luminance attenuation component according to the distance from the LED light source 500 was removed from the luminance distribution in Fig. 11. Fig. 12 shows the result after removing the luminance attenuation component.

[0069] 12, the luminance distribution has been obtained by removing the gradient component by removing the luminance attenuation component according to the distance from the LED light source 500. In this embodiment, the root mean square calculated from the luminance values ​​in FIG. 12 is defined as the effective value, and this effective value is used as the evaluation index.

[0070] (Method of obtaining maximum height Hx and maximum depth Dx) Fig. 15 is a diagram showing an example of the maximum height Hx of the convex portion 65 and the maximum depth Dx of the concave portion 622. Fig. 15 shows a part of the cross section of the shaped film 62 corresponding to the line III-III in Fig. 1.

[0071] The maximum height Hx is the difference in height between the top portion Tu, which is the highest portion of the convex portion 65, and the bottom portion Tb, which is the lowest portion of the convex portion 65. The maximum depth Dx is the difference in height between the shallow portion Ku, which is the highest portion of the concave portion 622, and the deep portion Kb, which is the lowest portion of the concave portion 622. In FIG. 15 , the bottom portion Tb and the shallow portion Ku are at the same height, so the symbols for the bottom portion Tb and the shallow portion Ku are shown together.

[0072] A laser microscope (VK-X1000) manufactured by Keyence Corporation was used to measure the maximum height Hx of the convex portions 65 and the maximum depth Dx of the concave portions 622 used in evaluating the brightness unevenness in the shaped film 62. The magnification of the objective lens was set to 150 times, and the shapes of the concave portions 622 and the convex portions 65 were measured from the main surface 621 side of the evaluation sample 400. Based on the shape measurement results, the maximum height Hx of the convex portions 65 and the maximum depth Dx of the concave portions 622 were obtained.

[0073] When the maximum height Hx of the convex portions 65 and the maximum depth Dx of the concave portions 622 are obtained using the shaped film 62 alone without using the light-transmitting substrate 401, the concave portions 622 and the convex portions 65 in the shaped film 62 are each cut so as to obtain a cross section parallel to the XZ plane. Then, the cross sections of the concave portions 622 and the convex portions 65 are observed with a laser microscope or the like, and the dimensions of the maximum height Hx and the maximum depth Dx can be measured by image measurement.

[0074] (Evaluation Results) The evaluation results of the luminance unevenness of the lighting device 100 including the shaped film 62 will be described with reference to Fig. 14 to Fig. 16. Fig. 14 is a diagram showing an example of an image of light emitted from the shaped film according to Example 1 obtained by the luminance unevenness evaluation. Fig. 15 is a diagram showing an example of an image of light emitted from the shaped film according to Comparative Example 1 obtained by the luminance unevenness evaluation. Fig. 16 is a diagram showing an example of the relationship between the ratio of the maximum height Hx of the convex portion 65 to the maximum depth Dx of the concave portion 622 and the effective value E.

[0075] The image shown in Fig. 14 is an image of a portion of the main surface 621 of the shaped film 62 according to Example 1. The image shown in Fig. 15 is an image of a portion of the main surface of the shaped film according to Comparative Example 2. The images shown in Figs. 14 and 15 were both obtained by the two-dimensional spectroradiometer 600.

[0076] Table 1 shows the results of obtaining the maximum height Hx, maximum depth Dx, Hx / Dx, and effective value E for each of Examples 1 to 6, Comparative Examples 1 and 2, as well as the results of the evaluation of brightness unevenness. The symbols shown in the evaluation column have the following meanings. "◎", "◯", and "△" indicate pass, while "×" indicates fail. ◎: No brightness unevenness was visible at all. ◯: Brightness unevenness was barely visible. △: Brightness unevenness was visible but not noticeable. ×: Brightness unevenness was significantly visible.

[0077] In the image obtained in Example 1 shown in Fig. 14, no brightness unevenness was visible at all. The same was true for Example 2. Therefore, Examples 1 and 2 were judged as "◎". Examples 3 and 6 were judged as "△", and Examples 4 and 5 were judged as "◯".

[0078] As shown in Fig. 15, in Comparative Example 1, streak-like brightness unevenness S extending in the Y direction was clearly visible. In the image shown in Fig. 15, high-brightness streaks (white portions) extending in the Y direction and low-brightness streaks (black portions) extending in the Y direction were observed. The same was true in Comparative Example 2. Therefore, Comparative Examples 1 and 2 were judged as "X".

[0079] 16, the horizontal axis represents Hx / Dx, which is the ratio of the maximum height Hx of the convex portion 65 to the maximum depth Dx of the concave portion 622, and the vertical axis represents the effective value E. Marks 151 indicated by black circles represent the results of Examples 1 to 6. Marks 152 indicated by black squares represent the results of Comparative Examples 1 and 6.

[0080] 16, it is found that if the effective value E is 0.2% or less, it is passed, and it is possible to reduce the luminance unevenness. Also, it is found from Table 1 that if the maximum height Hx is 0.09 μm or more and 0.30 μm or less, it is passed, and it is possible to reduce the luminance unevenness.

[0081] [Other Preferred Modifications] Fig. 17 is a schematic cross-sectional view showing a second example of the lighting device 100 including the shaped film according to the embodiment. Fig. 17 shows a part of the cross section corresponding to the line II-II in Fig. 1 in the second example of the lighting device 100.

[0082] In the second example of the lighting device 100 shown in Fig. 17 , the light guide layer 10 is disposed opposite the substrate 30. Light incident from the light source LS into the laminate 80 with a light guide layer is emitted from an exit surface 82 located on the opposite side to the light guide layer 10. The second example of the lighting device 100 is mainly different from the first example of the lighting device 100 shown in Fig. 2 in these respects.

[0083] 17 also provides the same effects as those of the embodiment. The light exit surface from which light exits the light-guiding layer-equipped laminate 80 may be at least one of the upper surface (the surface on the +Z side) and the lower surface (the surface on the −Z side) of the light-guiding layer-equipped laminate 80.

[0084] The laminate 80 with a light guide layer may have a low refractive index layer disposed on one side of the laminate 80 with a light guide layer and having a refractive index lower than that of the light guide layer 10 or the shaping film 62. The laminate 80 with a light guide layer may also have a low refractive index layer between the shaping film 62 and the substrate 30. The low refractive index layer preferably has a refractive index of 1.30 or less. The laminate 80 with a light guide layer may also have a hard coat layer or an anti-reflection layer.

[0085] The adherend on which the laminate 80 with a light guide layer is placed is not limited to glass, but may also be an electronic substrate such as a liquid crystal cell, or a non-light-transmitting member such as a ceiling, wall, or floor. The shaping film 62 is not limited to extracting light to the side opposite to the side on which the adherend is located, but may extract light to the side on which the adherend is located. In this case, if the adherend has high light transmittance, the extracted light may pass through the adherend, and if the adherend has low light transmittance, the adherend may reflect the light.

[0086] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0087] The ordinal numbers, quantities, and other figures used in the description of the embodiments are all provided as examples to specifically explain the technology of the present invention, and the present invention is not limited to the illustrated figures. Furthermore, the connection relationships between the components are provided as examples to specifically explain the technology of the present invention, and do not limit the connection relationships that realize the functions of the present invention.

[0088] The shaped film, the laminate, and the laminate with a light guide layer according to the embodiments can reduce brightness unevenness, and therefore, by combining them with a light source and placing them on building components such as glass, windows, walls, floors, and ceilings, it is possible to brightly illuminate the interior or exterior space of a building with reduced brightness unevenness. The same applies to the lighting device according to the embodiments.

[0089] Furthermore, the lighting device according to the embodiment can be used as a partition to suitably partition a room or conceal a desired space. Furthermore, by arranging the shape-transfer film, laminate, and laminate with a light guide layer according to the embodiment on a glass substrate of a display device such as a liquid crystal panel or an organic EL (Electro Luminescence) display panel, it is possible to brighten backlight illumination in the display device. In addition, the shape-transfer film, laminate, laminate with a light guide layer, and lighting device according to the embodiment can provide new uses other than those described above.

[0090] The aspects of the present invention are as follows, for example. <1> An optical shaped-transfer film having a main surface, wherein a plurality of recesses having inclined surfaces that totally reflect light are arranged in the formation direction at a first period P1 on the main surface, and a plurality of convex portions are arranged in the formation direction at a second period P2, and wherein, when the maximum depth of the recesses is Dx and the maximum height of the convex portions is Hx, Hx / Dx is 4% or less. <2> The shaped-transfer film according to <1>, wherein the maximum height Hx of the convex portions is 0.40 μm or less. <3> The shaped-transfer film according to <1> or <2>, wherein the maximum height Hx of the convex portions is 2 to 20 μm. <4> The shaped-transfer film according to any one of <1> to <3>, wherein the plurality of recesses are further arranged in the formation direction on the main surface in a direction intersecting the formation direction. <5> A laminate including the shaped film according to any one of <1> to <4> and a substrate disposed opposite the main surface of the shaped film. <6> A laminate with a light guide layer, including the laminate according to <5> and a light guide layer disposed opposite either the shaped film or the substrate. <7> A lighting device including the laminate with a light guide layer according to <6> and a light source disposed near an end face of the laminate with a light guide layer. <8> The lighting device according to <7>, in which light emitted from the light source enters the interior of the laminate with a light guide layer from at least one of the end face and an exit surface of the laminate with a light guide layer that intersects with the end face of the laminate with a light guide layer, is guided inside the laminate with a light guide layer, and then exits through the exit surface.

[0091] This application claims priority based on Japanese Patent Application No. 2024-055659 filed with the Japan Patent Office on March 29, 2024, and includes the entire contents of this Japanese patent application.

[0092] REFERENCE SIGNS LIST 10 light guide layer 30 substrate 52 first adhesive layer 54 second adhesive layer 60 direction conversion layer 62 shaped film 621 main surface 622 recess 64 cavity 65 protrusion 70 laminate 80 laminate with light guide layer 81 end surface 82 emission surface 100 lighting device 151, 152 mark 200 processing tool 300 mold 301 mold recess 302 mold protrusion 400 evaluation sample 401 light-transmitting substrate 402 end 500 LED light source 600 two-dimensional spectroradiometer C11, C12, C21, C22 center Dx maximum depth H height Hx maximum height ISa first inclined surface ISb second inclined surface Kb deep portion Ku shallow portion L length Lr Light LS Light source P1 First period P2 Second period Py Pitch S Luminance unevenness Tx, Tz Distance Tb Bottom Tu Top W Width θa, θb Inclination angle

Claims

1. An optical shaped film having a main surface, wherein a plurality of recesses having inclined surfaces that totally reflect light are arranged in a forming direction at a first period P1 on the main surface, and a plurality of protrusions are arranged in the forming direction at a second period P2, and wherein, when the maximum depth of the recesses is Dx and the maximum height of the protrusions is Hx, Hx / Dx is 4% or less.

2. The shaped film according to claim 1, wherein the maximum height Hx of the convex portion is 0.40 μm or less.

3. The shaped film according to claim 1, wherein the maximum height Hx of the convex portion is 2 to 20 μm.

4. The shaped film according to claim 1, wherein the plurality of recesses are further arranged on the main surface in a direction intersecting the forming direction.

5. A laminate comprising the shaped film according to any one of claims 1 to 4 and a substrate arranged opposite the main surface of the shaped film.

6. A laminate with a light guide layer, comprising the laminate according to claim 5 and a light guide layer disposed opposite either the shaping film or the substrate.

7. A lighting device comprising: a laminate with a light guide layer according to claim 6; and a light source disposed in the vicinity of an end face of the laminate with a light guide layer.

8. The lighting device according to claim 7, wherein light emitted from the light source enters the interior of the laminate with a light guide layer from at least one of the end face and an exit surface of the laminate with a light guide layer that intersects with the end face of the laminate with a light guide layer, is guided through the interior of the laminate with a light guide layer, and then exits through the exit surface.

Images