Decorative film for hidden displays

Abstract

The present invention relates to a decorative film for a hidden display, and more specifically, to a decorative film for a hidden display that, when the display is normally in an inactive state, displays the decorative film on the display surface, enhancing a sense of unity with the surrounding decorative film, and, when the user turns on the display and operates it, improves the user's visibility of the information displayed on the display while preventing delamination.

Description

[Technical Field]

[0001] The present invention relates to a decorative film for a hidden display, and more specifically, to a decorative film for a hidden display that is visible on the surface of the display when the display is normally inactive, improving the sense of visual unity with the surrounding decorative film, and that improves the user's visibility of the information displayed on the display when the user turns on the display and operates it, while preventing delamination. [Background technology]

[0002] Recently, displays, control switches, instrument functions, etc. have been added to not only vehicles but also home appliances and furniture due to the diversification of functions. In particular, in automobiles, as space becomes larger with the development of electric vehicles, the application of displays with various functions such as information and entertainment is increasing. As a result, the installation of control switches and displays becomes complex, reducing aesthetic appeal, while increasing demand for luxury and interior design in personal spaces.

[0003] For these reasons, decorative film for hidden displays has been developed. The increased number and size of displays can reduce the driver's concentration on driving, and the increased number of display buttons can cause inconvenience to drivers. Therefore, it is expected that the use of decorative film for hidden displays, which hides displays with designs similar to wood, leather, carbon fiber, etc., which are frequently used in vehicles, will increase.

[0004] 1a and 1b, a panel for a hidden display device that is normally invisible from the outside but becomes visible when an operational image is played has been developed. When installing a display device, the installation position can be conveniently adjusted and assembly is easy. However, there are drawbacks, such as the colored film changing the color displayed on the display or the display not appearing clearly when the display image is below 200 cd. Furthermore, when a metal coating is applied to enhance the shielding effect, the touch function of the display does not work. Furthermore, conventional technologies have been limited to the use of decorative films that display information and the image of the decorative film with low quality, resulting in limited transmission of text information and the color and image of the design film interfering with the information provided on the display and the interior. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a decorative film that allows the decorative film on the surface of the display to be visible when the display is normally in an inactive state, improving the sense of visual unity with the surrounding decorative film, and that improves the user's visibility of the information displayed on the display when the user turns on the display and operates it.

[0006] Another object of the present invention is to provide a decorative film for hidden displays that can prevent light distortion and light leakage, improve the design and aesthetics of the decorative film, have an improved information transmission function for the display, and effectively express the surface design of home appliances, car dashboards, etc., while preventing delamination. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a decorative film for a hidden display, which includes: a base layer; a pattern layer having at least one through hole; and a light guide layer having a base portion disposed between the base layer and the pattern layer, and at least one light guide portion having a protrusion extending from the base portion, passing through the through hole, and protruding above the through hole.

[0008] According to one embodiment of the present invention, the light guide may further include a shielding layer disposed on the pattern layer and having a through hole corresponding to the through hole, and the protrusion of the light guide may protrude above the through hole of the shielding layer.

[0009] The light guide may further include a base layer between the pattern layer and the shielding layer, the base layer having through holes corresponding to the through holes, and the light guide may pass through the through holes.

[0010] The refractive index of the light guide portion may be greater than the refractive index of the pattern layer or the refractive index of the base layer.

[0011] In addition, the difference in refractive index between the light guide portion and the pattern layer or the difference in refractive index between the light guide portion and the base layer may be greater than 0 and less than or equal to 0.5.

[0012] The light guide may further include a cover layer disposed on the pattern layer and covering the protrusions of the light guide.

[0013] The refractive index of the light guide portion may be greater than the refractive index of the cover layer.

[0014] The refractive index of the light guide may be 1.3 or more, and the refractive index of the cover layer may be 1.25 or more.

[0015] The light guide portion may have a vertical length of 5 to 90 μm.

[0016] Furthermore, the protrusion of the light guide portion may have a round shape with a predetermined curvature, and the protrusion may have a curvature radius of 2.5 to 260 μm.

[0017] Furthermore, the protrusion of the light guide may have a prism shape with at least two triangular prisms at its end, and the angle between the triangular prism and the adjacent triangular prism may be 70 to 100°.

[0018] The protrusion height of the protrusions may be more than 0 μm and 10 μm or less.

[0019] The light guide portion may have an average cross-sectional diameter of 10 to 500 μm.

[0020] The optical waveguide layer may include at least two optical guide portions, and the average distance between any one optical guide portion and an adjacent optical guide portion may be 20 to 500 μm.

[0021] In addition, the horizontal cross section of the light guide portion may have a wave shape including a curved long side and a straight or curved short side, and the length direction of the wave shape and the length direction of the decorative film for hidden display may form an angle of 20 to 50°.

[0022] The length of the wave shape may be 50 to 150 μm, and the distance between the long sides may be 5 to 50 μm.

[0023] The light guide portion may include an opaque portion that prevents light from passing through in at least a partial area.

[0024] In addition, the decorative film for hidden displays may be arranged so that one direction of lengthwise progression and the lengthwise direction of the corrugated shape form only one acute angle, or the decorative film for hidden displays may be arranged so that a first corrugated shape in which one direction of lengthwise progression and the lengthwise direction of the corrugated shape form an acute angle and a second corrugated shape in which one direction of lengthwise progression and the lengthwise direction of the corrugated shape form an obtuse angle are alternately arranged.

[0025] The present invention also provides a decorative film for a hidden display, comprising: a base layer; a pattern layer having at least one light passage hole; a shielding layer disposed on the pattern layer and having a light passage hole corresponding to the light passage hole; and an adhesive layer disposed between the base layer and the pattern layer.

[0026] According to an embodiment of the present invention, the light-emitting device may further include a base layer between the pattern layer and the shielding layer, the base layer including light passage holes corresponding to the light passage holes.

[0027] The term "on" used in the present invention includes both cases where one layer is placed on top of another layer so that the other layer is in contact with the top of the other layer, and where another layer is placed on top of one layer and another layer is included between them. [Effects of the Invention]

[0028] The decorative film for hidden displays of the present invention is designed so that when the display is normally inactive, the decorative film placed on the display surface is displayed, enhancing the sense of visual unity with the surrounding decorative film. When the user turns on the display and operates it, the user's visibility of the information displayed on the display is improved while also preventing delamination. [Brief explanation of the drawings]

[0029] [Figure 1a] 1 is a partial cross-sectional view illustrating an installation state of a conventional hidden display device; [Figure 1b] 1 is an exemplary diagram showing various configurations for installing a hidden display device; [Figure 2] 1 is a cross-sectional view of a decorative film for a hidden display according to one embodiment of the present invention. [Figure 3]1 is a SEM photograph showing a vertical cross section and a surface of a portion of a decorative film for a hidden display according to an embodiment of the present invention. [Figure 4a] 1 is a horizontal cross-sectional view of a decorative film for hidden display according to one embodiment of the present invention; [Figure 4b] 1 is a horizontal cross-sectional view of a decorative film for hidden display according to one embodiment of the present invention; [Figure 5] 10A and 10B are diagrams illustrating the state of light paths in a decorative film for hidden display with and without a light guide portion. [Figure 6] 10 is a cross-sectional view of a decorative film for a hidden display having prism-shaped protrusions according to another embodiment of the present invention. FIG. [Figure 7] 10 is a horizontal cross-sectional view illustrating the shape of a light guide portion in a decorative film for a hidden display having a light guide portion with a wave-shaped cross section according to another embodiment of the present invention. FIG. [Figure 8] 10 is a horizontal cross-sectional view illustrating the arrangement of opaque portions of a light guide portion in a decorative film for a hidden display having a light guide portion with a corrugated cross section according to another embodiment of the present invention. FIG. [Figure 9] 10 is a horizontal cross-sectional view illustrating the arrangement of a light guide portion in a decorative film for a hidden display having a light guide portion with a wave-shaped cross section according to another embodiment of the present invention. FIG. [Figure 10] 3 is a vertical cross-sectional view of a decorative film for a hidden display according to another embodiment of the present invention. [Figure 11] These are photographs showing the evaluation of visibility with and without the inclusion of an optical waveguide layer in a decorative film for hidden display according to one embodiment of the present invention, where (a) is a photograph of the display, (b) is a photograph of the case where an optical waveguide layer is included (Example 1), and (c) is a photograph of the case where only the pattern layer 13 is included without the optical waveguide layer (Comparative Example 1). [Figure 12]1 is a process flowchart illustrating a method for manufacturing a decorative film for a hidden display according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0031] This invention is a decorative film for hidden displays, and the image displayed to the user changes depending on whether the display is activated or deactivated.

[0032] That is, when the display is inactive, the printed pattern applied to the film is visible to the user, and when the display is active, the image on the display is displayed externally, and the information or image displayed on the display screen is visible to the user.

[0033] The application form of the present invention is to combine and apply it to the surface of a display for various electronic devices, but more preferably, it is applied not only to the display surface but also to the exterior surface of a product to which the display is attached, so that when the display is not in operation, the printed pattern is displayed simultaneously on the display surface and the exterior surface of the product, creating a sense of unity.

[0034] For example, when applied to a vehicle display, the decorative film for hidden display of the present invention can be combined with the surface of the AVN (Audio Video Navigation) and the surface of the dashboard of the vehicle.

[0035] The decorative film of the present invention can be applied to the exterior of various electronic devices combined with a display device, in addition to the vehicle display.

[0036] Hereinafter, a decorative film for a hidden display according to one embodiment of the present invention will be described.

[0037] As shown in FIG. 2, a decorative film 10 for a hidden display according to one embodiment of the present invention is embodied including a base layer 11, a pattern layer 13 having at least one through-hole, a base portion 12a disposed between the base layer 14 and the pattern layer 13, and a light guide layer 12 having at least one light guide portion 12b extending from the base portion 12a, passing through the through-hole, and having a protrusion protruding above the through-hole.

[0038] First, the base layer 11 will be described.

[0039] The base layer 11 supports the overall structure without negatively affecting the optical properties of the decorative film for hidden displays, is positioned closest to the user, protects the decorative film for hidden displays from chemical and physical impacts, and performs the function of realizing the texture of the pattern layer described below. The base layer 11 can be a known polymer film that is commonly used in the industry and has a predetermined transparency. For example, any one or a combination of two or more of PC (Polycarbonate) film, PMMA (Polymethyl methacrylate) film, and PET (Polyethylene Terephthalate) film can be used.

[0040] Furthermore, from the viewpoint of excellent processability, ease of installation, and light, thin, short, and small size, the thickness of the base layer 11 may be 5 μm to 2 mm, and preferably 10 μm to 1 mm, which may be advantageous from the viewpoint of realizing the above-mentioned effects.

[0041] In addition, the base layer 11 may be coated on one side with a hard coating such as anti-glare (AG), anti-reflection (AR), or low reflection (LR) to improve the handling properties and usability of the decorative film for hidden displays 10, such as preventing reflection and scattering. However, if it is expected that the optical properties of the decorative film for hidden displays will be affected, the hard coating may not be applied, and therefore, the present invention does not limit this.

[0042] Next, the optical waveguide layer 12 will be described.

[0043] The optical waveguide layer 12 functions to improve the visibility of display information when the display is operated, and as described above, the optical waveguide layer 12 includes a base portion 12a disposed between the base layer 14 and a pattern layer 13 (described later), and at least one or more optical guide portions 12b extending from the base portion 12a, passing through the through-holes, and having protrusions protruding above the through-holes.

[0044] Light emitted from the display is emitted to the outside via the light guide portion 12b, and information and images on the display are recognized by an external user on the base layer 11 side.

[0045] The base portion 12a and the light guide portion 12b may be formed of the same material or different materials, but preferably, they may be formed of the same material from the viewpoint of processability and preventing peeling between the base portion and the light guide portion due to heterogeneous bonding.

[0046] Furthermore, the optical waveguide layer 12 may be made of any transparent material available in the art, and preferably, one or more of acrylic resin, unsaturated polyester resin, epoxy resin, polyene resin, and acrylate ester resin may be used. More preferably, an acrylic resin, more preferably a UV-curable acrylic resin, may be used in order to increase the adhesion rate with the base layer 11 without affecting the visibility of the display image.

[0047] The base portion 12a may be flat and have a predetermined thickness, preferably 10 μm or less, and more preferably 5 μm or less, which may be advantageous from the viewpoint of stable adhesion to the base layer 11 described above.

[0048] The light guide portion 12b extends from the base portion 12a, passes through the through hole in a columnar shape, and has a protrusion that protrudes upward from the base portion 12a by a predetermined length. The optical waveguide layer 12 may include at least one light guide portion 12b, and preferably includes at least two light guide portions 12b.

[0049] Furthermore, the light guide portion 12b may have a vertical length of 3 to 100 μm, preferably 5 to 90 μm. When the light guide portion has a vertical length within this range, it is more advantageous in terms of ease of handling and improved quality.

[0050] The light guide 12b can improve the visibility of information displayed on the display by using internal reflection within the light guide 12b. Therefore, the light guide 12b may have a refractive index of 1.3 or more, preferably in the range of 1.4 to 1.55. When the light guide satisfies the refractive index range, light incident on the inside of the light guide 12b is internally reflected without being absorbed by other layers having through holes, allowing a large amount of light to be transmitted.

[0051] The refractive index of the light guiding unit 12b may be higher than the refractive index of the pattern layer 13 (to be described later) and / or the refractive index of the base layer 14 (to be described later). Preferably, the difference between the refractive index of the light guiding unit 12b and the refractive index of the pattern layer 13 or the difference between the refractive index of the light guiding unit 12b and the refractive index of the base layer 14 may be greater than 0 to 0.5. Thus, when light passing through the light guiding unit 12b, which has a relatively high refractive index, meets the boundary surface with the pattern layer 13 or the base layer 14, which has a relatively low refractive index, it is less likely to be absorbed at the boundary surface and internal reflection is induced, thereby increasing light transmittance and improving a user's visibility of images on the screen when the display is operated.

[0052] In addition, the light guide portion 12b has a protrusion formed on the upper part of the through hole, which increases the surface area exposed to the surface, thereby achieving the effect of increasing the introduction of light emitted from the display.

[0053] In addition, when the decorative film for hidden display according to the present invention further includes a shielding layer 15 described later, the protrusion may protrude above the through-hole of the shielding layer 15, and when the decorative film for hidden display according to the present invention includes both the base layer 14 and the shielding layer 15 described later, the protrusion may protrude above the through-hole of the shielding layer 15.

[0054] In this case, the protrusion height of the protrusions may be more than 0 μm and 10 μm or less, preferably 3 to 5 μm. By satisfying the protrusion height range of the protrusions, it may be more advantageous in terms of the effect of increasing the introduction of light emitted from the display.

[0055] The upper portion of the protrusion of the light guide 12b may have one or more shapes selected from the group consisting of a flat shape, an amorphous shape, a round shape, and a polygonal shape, and may have a round shape as shown in Figures 2 and 3 to enhance the optical effect. This allows the light emitted from the display to be refracted and more light to be collected and guided into the light guide 12b.

[0056] In this case, the round shape may be configured such that the entire protrusion is round, or the center of the upper end is flat and the edges are rounded, and the present invention is not particularly limited thereto.

[0057] Furthermore, as described above, when the refractive index of the light guide portion 12b, particularly the protrusion portion described above, is 1.3 or more and has a round shape, more display light is refracted inside the light guide portion 12b, allowing more light to pass through, thereby further improving the visibility of information transmitted from the display.

[0058] The protrusion at the upper end of the light guide portion 12b may have a curvature radius of 2.5 to 260 μm, preferably 3 to 250 μm. When the protrusion has a curvature radius within this range, it may be more advantageous in terms of improving visibility during display operation.

[0059] Furthermore, the protrusion at the upper end of the light guide 12b may have a predetermined unevenness on its surface, thereby dispersing light entering the display from the outside and enhancing the shielding effect. That is, when a predetermined uneven pattern is formed on the surface of the protrusion of the light guide 12b, the unevenness pattern disperses light entering the light guide from the outside when the display is not in use, thereby making it difficult for the user to see the presence of the display when the display is not in use. This has the effect of making the pattern of the decorative film on the display surface more clearly visible to the user when the display is not in use.

[0060] In addition, the cross-sectional shape of the light guide portion 12b may be circular as shown in FIGS. 4a and 4b, or may be various shapes such as elliptical, amorphous, polygonal, etc., and circular or elliptical shapes are preferred for ease of manufacturing.

[0061] In addition, the arrangement of the light guide portions 12b may be varied in various ways, such as being arranged at regular intervals or being arranged sporadically at irregular intervals, and the present invention does not particularly limit this.

[0062] The light guide 12b may have an average cross-sectional diameter 31 of 10 to 500 μm, preferably 12 to 480 μm, and more preferably 50 to 100 μm. If the average cross-sectional diameter of the light guide is less than 10 μm, image visibility is reduced, negatively affecting information transmission when the display is in operation. If the average cross-sectional diameter exceeds 500 μm, the display is visible even when the display is not in operation, resulting in no hidden display effect.

[0063] In this case, the cross-sectional diameters 31 of the light guide portions may all have the same cross-sectional diameter, or may be randomly configured to have different cross-sectional diameters.

[0064] In addition, the distance 32 between any one of the light guides and the adjacent light guide may be 20 to 500 μm, more preferably 50 to 150 μm. If the distance between the light guides is less than 20 μm, the shielding effect may be reduced, and the display shielding effect may be reduced. If the distance exceeds 500 μm, the visibility may be reduced when the display is in operation.

[0065] The light transmittance is determined by the cross-sectional diameter 31 of the light guide portion and the distance 32 between the light guide portions. The light transmittance is preferably 10 to 50%, more preferably 10 to 30%, and even more preferably 15 to 25%, taking into consideration the image visibility when the display is in operation and the display invisibility and pattern layer visibility when the display is not in operation.

[0066] In addition, the light guide portions 12b may be arranged regularly or irregularly. If they are arranged irregularly, it is possible to suppress the moiré phenomenon that may occur due to the mutual overlap between the pixel arrangement of the display and the arrangement of the light guide portions of the optical waveguide layer 12.

[0067] Furthermore, even when the light guide sections 12b are regularly arranged, the regularly arranged light guide sections may be tilted at an angle of 20 to 50°, more preferably 30 to 40°, relative to the horizontal direction of the decorative film for hidden displays. This makes it possible to suppress moiré, which may occur due to overlapping between the pixel array of the display and the array of the light guide sections of the optical waveguide layer 12, even when the light guide sections 12b are regularly arranged, through tilting.

[0068] 6, the protrusion of the light guide unit 12b' may have a prism shape with at least two triangular prisms at its end, and the angle between each triangular prism and its adjacent triangular prism may be 70 to 100°, preferably 85 to 95°, and the length of the base of the triangle in the cross section of each triangular prism may be 2 to 20 μm and the height may be 1 to 5 μm, preferably 2 to 4 μm and the height may be 1 to 3 μm. This improves the light collection effect and improves the user's visibility of the screen image when the display is activated.

[0069] Furthermore, depending on the shape of the light guide, the possibility of moire occurring due to interference with pixels repeatedly arranged on the display may increase. In particular, when the light guide is rectangular, the horizontal and vertical outer boundary lines of the rectangle and the horizontal and vertical outer boundary lines of the pixels are in the same direction, and moire may occur due to overlapping interference between them.

[0070] 7, the horizontal cross section of the light guide portion 12b may have a wave shape including a curved long side and a straight or curved short side, and the length direction S of the wave shape and the length direction H of the decorative film for hidden display may form an angle of 20 to 50°, preferably 30 to 40°, thereby preventing the occurrence of moire.

[0071] In this case, the length L of the corrugated shape may be 50 to 150 μm, the distance W between the long sides may be 5 to 50 μm, the horizontal distance d1 between the light guiding unit and another adjacent light guiding unit in the length direction of the decorative film for hidden display may be 30 to 200 μm, and the vertical distance d2 between the light guiding unit and another adjacent light guiding unit in the direction perpendicular to the length direction of the decorative film for hidden display may be 20 to 150 μm, which may be more advantageous in terms of preventing moire.

[0072] According to yet another embodiment of the present invention, the decorative film for a hidden display may include an opaque portion that blocks light transmission in at least a portion of the light guide. Preferably, the opaque portion may be arranged in different regions of each light guide depending on the arrangement order of the light guides in the decorative film for a hidden display. This may be more advantageous in terms of preventing moire. For example, the opaque portion of the first light guide and the opaque portion of the second light guide may be arranged in regions that do not overlap each other based on the horizontal cross section of the light guide, or may be arranged in regions that only partially overlap each other. Furthermore, depending on the arrangement order of the light guides in the decorative film for a hidden display, the opaque portions in each light guide may be arranged randomly or with a predetermined regularity. An example of an arrangement structure with a predetermined regularity for the arrangement of the opaque portions in each light guide will be described with reference to FIG. 8. For example, as shown in FIG. 8, the decorative film for a hidden display may include x×y light-guiding units 12b″ arranged in x rows and y columns (where x and y are natural numbers), and the light-guiding units 12b″ may include n divided regions formed by dividing the wave-shaped portions into n regions in the length direction (where n is a natural number). One of the divided regions may be an opaque portion, and the opaque portion in the xth row and yth column may be located in the x+y−1th divided region from the topmost divided region. If x+y−1 exceeds n, the opaque portion may be located in the x+y−1−nth divided region from the topmost divided region. This may be more advantageous in terms of preventing moire.

[0073] Furthermore, it is preferable that the light guide sections arranged in the x rows and y columns are defined as one block, and that a plurality of the blocks are arranged continuously in the horizontal and vertical directions across the entire area of ​​the film. In this case, it is easy to apply a moire avoidance pattern even when the film is applied to a large-area display of a predetermined size or larger.

[0074] According to yet another embodiment of the present invention, the light guiding units 12b" may be arranged so that one longitudinal direction of the decorative film for a hidden display and the longitudinal direction of the corrugated shape form only one acute angle, or as shown in FIG. 9, the light guiding units may be arranged so that a first corrugated shape 12b"1 in which one longitudinal direction of the decorative film for a hidden display and the longitudinal direction E of the corrugated shape form an acute angle and a second corrugated shape 12b"2 in which the longitudinal direction F of the corrugated shape form an obtuse angle are alternately arranged. This may be more advantageous in terms of preventing moire generation.

[0075] Next, the pattern layer 13 will be described.

[0076] The pattern layer 13 is formed to a predetermined thickness and is a layer on which a pattern that can be seen by a user is formed when the display is not in operation.

[0077] The pattern layer 13 may be a single color such as black, white, or a specific color, or may have an interior pattern with various colors applied. Such a pattern layer may be printed with ink. For example, oil-based, water-based, or UV ink may be used. Various printing methods such as gravure, offset, flexo, laser, digital, and screen printing are available, and can be selected depending on the amount and clarity of printing.

[0078] Next, the underlayer 14 will be described.

[0079] According to an embodiment of the present invention, a base layer 14 having through holes corresponding to the through holes may be further included between the pattern layer 13 and a shielding layer 15 described later, and in this case, the light guide parts 12b can pass through the through holes.

[0080] The base layer 14 is formed with a predetermined thickness between the pattern layer 13 and the shielding layer 15 (described later) to enhance the clarity of the image printed on the pattern layer 13. It can be painted with white or a color that is brighter than the image. In this case, the base layer 14 can be made of the same ink as the pattern layer 13, or an oil-based or water-based coating or paste-type material.

[0081] The material of the base layer 14 can be various materials as long as they have good bonding with the printing ink of the pattern layer, and the material of the base layer can be selected depending on whether or not a touch display is required.

[0082] Next, the shielding layer 15 will be described.

[0083] According to one embodiment of the present invention, the decorative film 10 for hidden display may further include a shielding layer 15 disposed on the pattern layer 13 and having through holes corresponding to the through holes.

[0084] The shielding layer 15 is formed on the pattern layer 13 with a predetermined thickness to prevent light from leaking from areas other than the light guide portion 12. It can be printed with black or a low-saturation color and can be coated with the same material as the pattern layer 13 and / or the base layer 14 or with other materials.

[0085] It should be noted that, depending on the color pattern printed on the pattern layer 13, only one of the base layer 14 and the shielding layer 15 may be applied, or neither the base layer 14 nor the shielding layer 15 may be applied. In other words, if the pattern printed on the pattern layer 13 is expressed in a dark color or a single color, the base layer 14 may be omitted and only the shielding portion 15 may be applied on the upper surface of the pattern layer 13, or if the color printed on the pattern layer 13 is expressed in only black or white, neither the base layer 14 nor the shielding portion 15 may be applied. However, the present invention is not particularly limited thereto.

[0086] The material of the shielding layer 15 may be black or a low-saturation material, and the material may be selected depending on the display performance. Also, various materials may be used as long as they are well combined with the material of the pattern layer or the material of the base layer. The material of the shielding layer may be selected depending on whether or not a touch display is used.

[0087] As an example of combining the decorative film 10 for hidden display according to one embodiment of the present invention with a display, the decorative film for hidden display is first combined with the outer surface of the exterior material, the display is combined with the inner surface of this exterior material, and the decorative film for hidden display is positioned in front of the display, resulting in a structure in which the two are combined with each other.

[0088] For example, when a decorative film for a hidden display is bonded to the outer surface of the exterior material, the decorative film for a hidden display can be attached and bonded to the outer surface of a pre-fabricated exterior material using an adhesive.

[0089] Alternatively, as another example, when a decorative film for a hidden display is bonded to the outer surface of the exterior material, when the exterior material is manufactured using the injection molding method, the decorative film for a hidden display is placed in a mold in advance, and the exterior material is manufactured by injecting resin into the mold and is bonded integrally with the decorative film for a hidden display.

[0090] Here, the decorative film for hidden display 10 may have a risk of the pattern layer 13, the base layer 14, the shielding layer 15, or the light guide portion 12b melting and breaking due to high resin temperature during resin injection into the mold. To prevent this, a cover layer may be further formed with a predetermined thickness on the pattern layer 13, the base layer 14, or the shielding layer 15 to cover the protrusions of the light guide portion 12b.

[0091] The cover layer may be formed by applying a transparent UV-curable resin made of an acrylate monomer material.

[0092] Alternatively, the cover layer may be formed by separately attaching a durable film with an adhesive.

[0093] In this case, the adhesive layer may be made of transparent UV OCA, heat-cured OCA, etc., and the durable film may be made of PC (Polycarbonate) film, PMMA (Polymethyl methacrylate) film, PET film, etc.

[0094] The cover layer may be formed to have a thickness of 5 to 60 μm so as to be able to withstand the high temperature of the injected resin.

[0095] The refractive index of the cover layer may be smaller than that of the light guide portion 12b. In this case, the refractive index of the cover layer may be 1.25 or more, preferably 1.35 to 1.54. The difference between the refractive index of the cover layer and that of the light guide portion may be greater than 0 and less than 0.05. This allows light emitted from the display to be easily introduced and collected from the cover layer to the optical waveguide layer 12.

[0096] In addition, when the decorative film 10 for a hidden display according to another embodiment of the present invention is attached to the front of the display, the direction in which the decorative film is attached may be reversed.

[0097] That is, the base layer of the decorative film for hidden display 10 is disposed close to and faces the display screen, and the light guide portion is disposed relatively far from the display.

[0098] In this case, between the light guide parts, the shielding layer 15, the base layer 14, and the pattern layer 13 are laminated in this order from the base part. The laminated shielding layer 15, the base layer 14, and the pattern layer 13 may be partially removed.

[0099] FIG. 5 is a diagram showing the state of the light path in the decorative film for hidden display 10 with and without the light guide portion 12b.

[0100] As shown in FIG. 5, a portion of the light emitted from the display screen is absorbed and blocked by the shielding layer 15, and the remaining light is incident on the protrusions of the light guide portions 12b, refracted internally, and travels along the inside of the light guide portions 12b through the base portion 12a and the base layer 11 to be displayed externally and viewed by the user.

[0101] During this process, the light that strikes the interior of the light guide portion 12b and the boundary between the adjacent base layer 14 and pattern layer 13 is reflected at the boundary because the refractive index of the light guide portion 12b is higher than the refractive index of the base layer 14 and pattern layer 13, thereby increasing the light transmittance.

[0102] In particular, the light guide portion 12b has a protrusion protruding higher than the shielding layer 15, and the light enters through the protrusion and exits to the outside through internal reflection, thereby increasing the light utilization efficiency through such a tunnel effect.

[0103] When a passage in a spatial state is formed in the decorative film where the position of the light guide section 12b is empty, only light that enters this passage perpendicularly passes through the decorative film, and light that enters this passage at a certain angle of incidence other than perpendicularly is absorbed when it abuts on one or more of the internal wall surfaces of the adjacent pattern layer 13, base layer 14, and shielding layer 15, resulting in a relatively low light transmittance.

[0104] As shown in FIG. 10, a decorative film 20 for a hidden display according to another embodiment of the present invention is embodied as including a base layer 21, a pattern layer 23 having at least one light passage hole 26, a shielding layer 15 disposed on the pattern layer 23 and having a light passage hole 26 corresponding to the light passage hole 26, and an adhesive layer 22 disposed between the base layer 21 and the pattern layer 23.

[0105] In addition, the decorative film 20 for hidden display according to another embodiment of the present invention may further include a base layer 24 having light passage holes 26 corresponding to the light passage holes 26 between the pattern layer 23 and the shielding layer 15.

[0106] In the following description of the decorative film 20 for hidden display according to another embodiment of the present invention, the description of the base layer 21, pattern layer 23, base layer 24 and shielding layer 25, which are the same as those described in the description of the decorative film 10 for hidden display according to one embodiment of the present invention, will be omitted.

[0107] The adhesive layer 22 is formed between the base layer 21 and the pattern layer 23, and the pattern layer 23 is attached to the base layer 21 by the adhesive layer 22. In this case, the adhesive layer 22 can be applied as a transparent OCA.

[0108] The light passage hole 26 is formed in a hole shape penetrating the pattern layer 23, the underlayer 24 and the shielding layer 25, and at least one, preferably a plurality of, light passage holes 26 are formed at predetermined intervals.

[0109] The explanation regarding the planar arrangement and spacing of the light passage holes is omitted here, as it is the same as the explanation regarding the arrangement and spacing of the light guide portions 12b mentioned in the decorative film 10 for hidden display according to one embodiment of the present invention.

[0110] Further, the description of the cross-sectional diameter of each light passage hole 26 is the same as the description of the cross-sectional diameter 31 of the light guide portion in the first embodiment, and therefore will be omitted.

[0111] In addition, in the decorative film 20 for hidden display according to another embodiment of the present invention, the light passage holes 26 may be filled with a general transparent binder to protect each layer, or the light passage holes 26 may be filled with air, so the present invention is not particularly limited thereto.

[0112] In addition, the decorative film 20 for a hidden display according to another embodiment of the present invention can be used by being attached to the surface of the display in the direction of the shielding layer 25.

[0113] The decorative film 20 for hidden display according to another embodiment of the present invention can be manufactured according to the manufacturing method described below.

[0114] For example, the decorative film 20 for a hidden display according to another embodiment of the present invention can be manufactured by removing the base layer 11 and the optical waveguide layer 12 from the decorative film 10 for a hidden display according to one embodiment of the present invention.

[0115] Alternatively, the shielding layer 25, the base layer 24, and the pattern layer 23 may be laminated in this order, an adhesive may be applied to the upper surface of the pattern layer 23 to form the adhesive layer 22, and then the adhesive layer 22 may be attached to the upper surface of the base layer 21 so that the adhesive layer 22 abuts against the upper surface of the base layer 21, thereby manufacturing a decorative film 20 for a hidden display according to another embodiment of the present invention.

[0116] The decorative film 20 for hidden displays according to another embodiment of the present invention can be used mainly as a transfer type or an adhesive type. It can be used without the base film 21. When the base film 21 is not present, it can be used as a transfer type, and when the base film 21 is present, it can be used by adhering to the display.

[0117] In addition, to explain the operation of the decorative film 20 for hidden display according to another embodiment of the present invention, a portion of the light emitted from the display screen is absorbed and blocked by the shielding layer 25, and the remaining light is introduced into a number of light passage holes 26, passes through the light passage holes 26, and is emitted to the outside, through which the display screen information can be viewed by an external user.

[0118] In addition, when the display is normally inactive, the decorative film for hidden displays of the present invention displays the decorative film on the surface of the display, enhancing the sense of unity with the surrounding decorative film.When the user turns on the display and operates it, the user's visibility of the information displayed on the display is improved, while at the same time preventing delamination. [Example]

[0119] The present invention will be described in more detail based on the following examples. However, it should be understood that the following examples are not intended to limit the scope of the present invention, but are intended to aid in the understanding of the present invention.

[0120] <Example 1: Production of decorative film for hidden display> First, a light guide layer was formed as a pattern layer using a polymer mold on a 250 μm thick base layer made of a PC (Polycarbonate) film. The light guide layer had a 3 μm thick base made of a UV-curable acrylic resin and a plurality of light guides extending from the base, each with a circular cross section and arranged at equal intervals as shown in Figure 4a. A latex ink was then applied to a digital printer to form a pattern layer with through holes and a thickness of 1 μm, with the through holes passing through the light guides. White carbon paste was then applied to the pattern layer with a blade to form a 2 μm thick base layer with through holes. Black carbon paste was then applied to the base layer with a blade to form a 2 μm thick shielding layer with through holes, with the through holes passing through the light guides. This produced a decorative film for a hidden display. In this case, the refractive index of the light guide portion is 1.5, the vertical length is 10 μm, the average cross-sectional diameter is 50 μm, and the distance between adjacent light guide portions is 150 μm. The light guide portion passes through the through hole and forms a protrusion that protrudes from the upper part of the through hole, and the protrusion has a round shape with a curvature radius of 10 μm and a protrusion height of 4 μm.

[0121] <Examples 2 to 12> The decorative films for hidden displays were manufactured in the same manner as in Example 1, but by changing the average cross-sectional diameter of the light guide portions, the distance between adjacent light guide portions, the refractive index of the light guide portions, the curvature radius of the protrusions, etc., as shown in Tables 1 to 3.

[0122] <Comparative Example 1> It was produced in the same manner as in Example 1, except that it was produced without the light guide layer, underlayer and shielding layer, and only a pattern layer without through holes was printed on the underlayer.

[0123] <Experimental Example> The decorative films for hidden displays prepared in the examples and comparative examples were fixed on a display panel with the shielding layer side facing up, and the following physical properties were evaluated and shown in Tables 1 to 3.

[0124] 1. Measuring the ratio of emitted light to incident light For the decorative films for hidden displays manufactured in the examples and comparative examples, the ratio of the amount of light emitted to the base layer to the amount of light incident on the decorative film for hidden displays during display operation was measured using a KONICA MINOLTA CA-310 device at a measurement angle of 2.5°, a measurement distance of 35 mm, and a measurement diameter of Φ27 mm. The light amount ratio measured in Example 1 was then converted and applied as 100, and the light amount ratios of the other examples and comparative examples were converted and calculated based on this.

[0125] 2. Visibility (when the display is activated) and non-visibility (when the display is inactivated) evaluation The decorative films for hidden displays prepared in the examples and comparative examples were evaluated for display visibility when the display was in operation and for display invisibility when the display was not in operation. Specifically, 10 experts with more than 10 years of experience in the industry evaluated the display visibility when the display was in operation and the display invisibility when the display was not in operation using a 7-point scale.

[0126] *Evaluation criteria for display visibility when the display is in operation 7 points: very good visibility, 6 points: good visibility, 5 points: slightly good visibility, 4 points: normal visibility, 3 points: slightly poor visibility, 2 points: poor visibility, 1 point: very poor visibility *Evaluation criteria for display invisibility when the display is not in operation 7 points: very good invisibility, 6 points: good invisibility, 5 points: slightly good invisibility, 4 points: average invisibility, 3 points: slightly poor invisibility, 2 points: poor invisibility, 1 point: very poor invisibility

[0127] [Table 1]

[0128] [Table 2]

[0129] [Table 3]

[0130] As is clear from Tables 1 to 3, Examples 1, 3, 6, 9, and 10, which satisfy all of the average cross-sectional diameter of the light guide portion, the distance between adjacent light guide portions, the refractive index of the light guide portion, the curvature radius of the protrusions, and whether or not the optical waveguide layer contains an inclusion, have a relatively high ratio of the amount of emitted light to incident light, and thus exhibit excellent visibility when the display is in operation and excellent invisibility when the display is not in operation, compared to Examples 2, 4, 5, 7, 8, 11, and 12 and Comparative Example 1, which do not satisfy any of these.

[0131] In particular, as shown in FIG. 11, it was confirmed that the visibility of the display screen was significantly reduced in Comparative Example 1 (FIG. 11c) compared to Example 1 (FIG. 11b) when the display was operated.

[0132] Although one embodiment of the present invention has been described above, the concept of the present invention is not limited to the examples presented in this specification, and a person skilled in the art who understands the concept of the present invention can easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same concept, which can also be said to fall within the scope of the concept of the present invention.

Claims

1. the base layer; a pattern layer having at least one through hole; A decorative film for a hidden display, comprising: a light guide layer having a base portion disposed between the base layer and the pattern layer; and at least one light guide portion extending from the base portion, passing through the through holes, and having a protrusion formed on the top of the through holes.

2. a shielding layer disposed on the pattern layer and having through holes corresponding to the through holes; The decorative film for a hidden display according to claim 1 , wherein the protrusion of the light guide protrudes above the through-hole of the shielding layer.

3. a base layer between the pattern layer and the shielding layer, the base layer having through holes corresponding to the through holes; The decorative film for a hidden display according to claim 2 , wherein the light guide portion passes through the through-hole.

4. The decorative film for a hidden display according to claim 3 , wherein the refractive index of the light guide portion is greater than the refractive index of the pattern layer or the refractive index of the base layer.

5. The decorative film for hidden display according to claim 4, wherein the difference in refractive index between the light guiding portion and the pattern layer or the difference in refractive index between the light guiding portion and the base layer is greater than 0 and less than 0.

5.

6. The decorative film for hidden display according to claim 1 , further comprising: a cover layer disposed on the pattern layer and covering the protrusions of the light guide portion.

7. The decorative film for a hidden display according to claim 6 , wherein the refractive index of the light guide portion is greater than the refractive index of the cover layer.

8. The refractive index of the light guide portion is 1.3 or more, 7. The decorative film for a hidden display according to claim 6, wherein the refractive index of the cover layer is 1.25 or more.

9. 2. The decorative film for a hidden display according to claim 1, wherein the light guide portion has a vertical length of 5 to 90 μm.

10. 2. The decorative film for hidden display according to claim 1, wherein the protrusion of the light guide portion has a round shape with a predetermined curvature, and the protrusion has a curvature radius of 2.5 to 260 μm.

11. The decorative film for hidden display according to claim 1, wherein the protrusion of the light guide portion has a prism shape with at least two triangular prisms at its end, and the angle between the triangular prism and the adjacent triangular prism is 70 to 100 degrees.

12. 4. The decorative film for hidden display according to claim 1, wherein the protrusions have a protrusion height of more than 0 μm and 10 μm or less.

13. 2. The decorative film for hidden display according to claim 1, wherein the light guide portion has an average cross-sectional diameter of 10 to 500 μm.

14. the optical waveguide layer includes at least two optical guide portions; 2. The decorative film for hidden display according to claim 1, wherein the average distance between any one light guide portion and an adjacent light guide portion is 20 to 500 μm.

15. 2. The decorative film for hidden displays according to claim 1, wherein the horizontal cross section of the light guide portion has a wave shape including a curved long side and a straight or curved short side, and the length direction of the wave shape and the length direction of the decorative film for hidden displays form an angle of 20 to 50 degrees.

16. 16. The decorative film for hidden display according to claim 15, wherein the length of the wave shape is 50 to 150 μm, and the distance between the long sides is 5 to 50 μm.

17. The decorative film for hidden display according to claim 1 or 15, wherein the light guide portion includes an opaque portion that prevents light from passing through in at least a part of the region.

18. The decorative film for hidden display is arranged so that one longitudinal direction thereof and the longitudinal direction of the corrugated shape form only one acute angle, or A decorative film for hidden displays as described in claim 15, wherein a first wave shape in which one direction of the length of the decorative film for hidden displays forms an acute angle with the length direction of the wave shape and a second wave shape in which the first wave shape forms an obtuse angle are arranged alternately.

19. the base layer; a pattern layer having at least one light passage hole; a shielding layer disposed on the pattern layer and having light passage holes corresponding to the light passage holes; and an adhesive layer disposed between the base layer and the pattern layer.

20. 20. The decorative film for hidden display according to claim 19, further comprising: a base layer between the pattern layer and the shielding layer, the base layer including light passage holes corresponding to the light passage holes.

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