Retro-reflective sheet having optical interference layer and manufacturing method therefor

Abstract

A retro-reflective sheet having an optical interference layer according to an embodiment of the present invention comprises: glass beads applied to a diffusion film of a polyethylene film (PE film) and a polyethylene terephthalate film (PET film); an optical interference layer deposited on the glass beads; a color layer coated on the optical interference layer; and a backing substrate attached to the color layer by an adhesive resin layer, wherein the optical interference layer may be composed of an optical interference thin film layer with ZnS deposited thereon.

Description

Retroreflective sheet having an optical interference layer and method of manufacturing the same

[0001] The present invention relates to a retroreflective sheet having an optical interference layer and a method for manufacturing the same. The present invention relates to a retroreflective sheet having an optical interference layer and a method for manufacturing the same.

[0002] A retroreflective sheet can refer to a reflector that includes a light-collecting layer and a reflective layer, which reflects incident light back in the same direction as it was incident.

[0003] Retroreflective sheets are typically formed in the shape of a sheet and processed into a desired shape or pattern on the surface of the body of the object to be attached by methods such as heat pressing or sewing to selected parts of road signs or firefighter uniforms, thereby improving visibility and enabling easy display even in dark surrounding environments.

[0004] Therefore, if retroreflective sheets are attached to the clothing worn by people working on roads or in dangerous places, such as sanitation workers, firefighters, police officers, factory workers, construction site workers, and safety personnel in various fields, the wearer's location can be clearly identified to those around them, thereby providing significant protection and safety for the wearer.

[0005] In addition, retroreflective sheets are applied to trademarks, symbols, or decorations on everyday clothing and athletic shoes. Previously, it was common for retroreflective sheets to display silver-toned colors due to the reflective layer, but for this reason, there is a growing need for them to display a variety of colors.

[0006] Accordingly, the inventor of the present invention has completed the present invention after conducting research and going through trial and error for a long time to develop technology for a retroreflective sheet having an optical interference layer configured to enhance the rainbow effect (iridescent effect) or color change effect by applying a metal or metal oxide or inorganic oxide having a specific refractive index for each wavelength band, and to minimize light loss through the matching of a composite optical interference layer of an optical interference thin film layer, thereby realizing an improvement in brightness by maximizing retroreflectivity.

[0007] According to one embodiment of the present invention, a retroreflective sheet and a method for manufacturing the same can be provided, configured to enhance brightness by applying a metal or metal oxide or inorganic oxide having a specific refractive index for each wavelength band to increase the rainbow effect (iridescent effect) or color change effect, while minimizing light loss through the matching of a composite optical interference layer of an optical interference thin film layer.

[0008] Meanwhile, other unspecified objects of the present invention will be further considered to the extent that they can be easily inferred from the following detailed description and effects.

[0009] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention is a retroreflective sheet comprising glass beads coated on a dispersion film of a PE film (polyethylene film) and a PET film (polyethylene terephthalate film), an optical interference layer deposited on the glass beads, a color layer coated on the optical interference layer, and a backing substrate adhered to the color layer by an adhesive resin layer, wherein the optical interference layer may be composed of an optical interference thin film layer on which ZnS is deposited.

[0010] The above optical interference thin film layer can be formed by depositing ZnS with a thickness of 600 to 1000 nm.

[0011] The above optical interference thin film layer can be deposited to have one or more layers of the same material or different materials.

[0012] The above optical interference thin film layer can be deposited by thermal evaporation or sputtering.

[0013] A method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention comprises: (a) a step of manufacturing a dispersion film by laminating a PE film and a PET film; (b) a step of applying glass beads to the PE film; (c) a step of depositing an optical interference layer on the surface of the glass beads; (d) a step of forming a color layer by coating a color thin film on the optical interference layer; (e) a step of forming an adhesive resin layer by coating an organic hybrid coating solution on the color layer; and (f) a step of adhering a backing substrate to the adhesive resin layer, wherein the optical interference layer may be composed of an optical interference thin film layer having ZnS deposited thereon.

[0014] When the retroreflective sheet is completed in step (f) above, (g) a step of removing the scatter film from the glass beads may be further included.

[0015] In step (c) above, the optical interference thin film layer may be deposited by thermal evaporation or sputtering.

[0016] In step (c) above, the optical interference thin film layer can be deposited at a setting voltage (V) of 8.5 to 10.0.

[0017] In step (c) above, the optical interference thin film layer may be formed by depositing ZnS with a thickness of 600 to 1000 nm.

[0018] In step (c) above, the optical interference thin film layer may be deposited to have one or more layers of the same material or different material.

[0019] According to one embodiment of the present invention, in a retroreflective sheet having an optical interference layer and a method for manufacturing the same, various color conditions can be realized through refractive index matching, color deviation in the width and length directions can be significantly reduced, and physical properties can be maximized by applying various manufacturing methods, thereby providing substantial and practical effects.

[0020] Meanwhile, it should be added that even if an effect is not explicitly mentioned here, the effects described in the following specification and the provisional effects expected by the technical features of the present invention are treated as described in the specification of the present invention.

[0021] FIG. 1 is a cross-sectional view illustrating a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0022] FIG. 2 is a cross-sectional view illustrating an optical interference layer of a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0023] FIG. 3 is a cross-sectional view illustrating an optical interference layer of a retroreflective sheet having an optical interference layer according to another embodiment of the present invention.

[0024] Figure 4 is a schematic diagram explaining the evaporation and sputtering methods of PVD.

[0025] Figure 5 is a schematic diagram explaining the deposition state by evaporation and sputtering in PVD.

[0026] FIG. 6 is a schematic diagram illustrating various film formations of an optical interference layer by sputtering in a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0027] FIG. 7 is a flowchart illustrating a method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0028] FIG. 8 is an illustrative diagram explaining Example 1 and Example 2.

[0029] It should be noted that the attached drawings are provided as examples for reference to help understand the technical concept of the present invention, and the scope of the rights of the present invention is not limited by them.

[0030] In describing the present invention, detailed descriptions of related known functions are omitted if they are deemed obvious to a person skilled in the art and could unnecessarily obscure the essence of the invention.

[0031] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0032] The size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and therefore the present invention is not necessarily limited to what is illustrated. In the drawings, the first direction may be defined as the length direction or the extension direction of the roadway, the second direction as the width direction, and the third direction as the height direction.

[0033] Hereinafter, embodiments of a retroreflective sheet having an optical interference layer according to the present invention and a method for manufacturing the same will be described in detail with reference to the accompanying drawings. In describing with reference to the accompanying drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted.

[0034] FIG. 1 is a cross-sectional view illustrating a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0035] As illustrated in FIG. 1, a retroreflective sheet having an optical interference layer according to an embodiment of the present invention may have glass beads (100) applied to the PE film (20) in a dispersion film prepared by laminating a PE film (polyethylene film) (20) and a PET film (polyethylene terephthalate film) (10), and an optical interference layer (400) as a reflective layer may be deposited on the glass beads (100) applied to the PE film (20) of the dispersion film.

[0036] In addition, a retroreflective sheet having an optical interference layer according to an embodiment of the present invention may have a color layer (30) coated on the optical interference layer (400) of a glass bead (100).

[0037] At this time, the color layer (30) can be formed by coating a single layer or a multilayer color film after thin film coating pretreatment such as halogen heating treatment and plasma surface treatment on the optical interference layer (400).

[0038] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be manufactured by forming an adhesive resin layer (40) by coating an organic hybrid coating solution on a color layer (30), and then bonding a backing substrate (50) using the adhesive resin layer (40) to form a laminate.

[0039] At this time, the backing material (50) is used when attaching a retroreflective sheet to the surface of a product such as shoes or clothing by heat pressing, and can be formed from a sheet formed of a thermoplastic resin such as polyester, polyurethane, polyacrylic, polyolefin, TPE (Thermo Plastic Elastomer) or TPU (Thermoplastic Polyurethane).

[0040] In addition, the backing material (50) may be formed of a cloth or non-woven fabric, and the retroreflective sheet may be sewn and attached to a product such as shoes or clothing.

[0041] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be applied for use after removing a dispersion film, which is formed by laminating a PE film (polyethylene film) (20) and a PET film (polyethylene terephthalate film) (10) from a glass bead (100) once the product is completed.

[0042] FIG. 2 is a cross-sectional view illustrating an optical interference layer of a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0043] As illustrated in FIG. 2, a retroreflective sheet having an optical interference layer according to one embodiment of the present invention can be configured such that an optical interference layer (400), which is a reflective layer, is deposited on the surface of a glass bead (100).

[0044] At this time, the optical interference layer (400) functioning as a reflective layer may be composed of a double optical interference layer (200), and the double optical interference layer (200) may be formed to consist of a first optical interference layer (210) and a second optical interference layer (220).

[0045] Thus, in a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, the double optical interference layer (200) can be formed such that after a first optical interference layer (210) is deposited on the surface of a glass bead (100), a second optical interference layer (220) is deposited on the surface of the first optical interference layer (210).

[0046] Here, the double optical interference layer (200) can be made of any one of Al, TiN, Ti, Cr, or Ni-Cr in the case of the first optical interference layer (210) deposited on the surface of the glass bead (100).

[0047] Additionally, the double optical interference layer (200) may be configured to deposit a second optical interference layer (220) of ZnS on the surface of a first optical interference layer (210) made of any one of Al, TiN, Ti, Cr, or Ni-Cr.

[0048] Conversely, the double optical interference layer (200) can be applied such that if the first optical interference layer (210) is deposited as ZnS, the second optical interference layer (220) is deposited as any one of Al, TiN, Ti, Cr, or Ni-Cr.

[0049] In particular, the double optical interference layer (200) can be controlled to have a thickness of 600 to 1000 nm when deposited with ZnS, and can be controlled to have a thickness of 10 to 100 nm when deposited with any one of Al, TiN, Ti, Cr, or Ni-Cr.

[0050] Additionally, the double optical interference layer (200) can be formed as a single layer through a single thin film deposition process, but if it is formed as m layers through m (m is a natural number greater than or equal to 2) thin film deposition processes, excellent adhesion between the substrate and the thin film layer is achieved, and the bonding strength between the thin film layers is improved, thereby substantially improving the physical properties and appearance of the thin film through the interface phenomenon of the thin film deposition.

[0051] The double optical interference layer (200) can be formed by double film deposition of the first optical interference layer (210) and the second optical interference layer (220), thereby forming a metal reflective layer mixed with a thin film of any one of Al, TiN, Ti, Cr, Ni-Cr and a thin film of ZnS, and thereby can achieve an improvement in brightness and a rainbow effect through composite optical interference layer matching.

[0052] FIG. 3 is a cross-sectional view illustrating an optical interference layer of a retroreflective sheet having an optical interference layer according to another embodiment of the present invention.

[0053] As illustrated in FIG. 3, the optical interference layer (400) of a retroreflective sheet having an optical interference layer according to another embodiment of the present invention may be composed of a triple optical interference layer (300), and the triple optical interference layer (300) may be formed to consist of a first optical interference layer (310), a second optical interference layer (320), and a third optical interference layer (330).

[0054] At this time, the triple optical interference layer (300) of the optical interference layer (400) forms a triple optical interference layer according to the refractive index, and the matching of the wavelength range and thickness of each layer and the composite optical interference layer can be realized, and from this, various color shift effects can be derived, so that the rainbow effect can be maximized.

[0055] To this end, the triple optical interference layer (300) of the optical interference layer (400) may be formed to have a first optical interference layer (310) of high refractive index, a second optical interference layer (320) of low refractive index, and a third optical interference layer (330) of high refractive index.

[0056] Light has the characteristic of determining a path to reach two different points in the shortest possible time when traveling. The degree to which light bends in a medium is defined as the refractive index (RI), and the refractive index can generally vary depending on the wavelength of light.

[0057] At this time, as high and medium refractive index materials, the refractive index of ZnS is 2.40, the refractive index of TiO2 is 2.52, the refractive index of In2O3 is 2.00, the refractive index of ZrO2 is 2.40, the refractive index of Al2O3 is 1.76, and the refractive index of MgO is 1.74.

[0058] And, as low-refractive index materials, the refractive index of SiO2 is only 1.46, the refractive index of NaF is about 1.29, the refractive index of CaF2 is 1.44, and the refractive index of MgF2 is 1.38.

[0059] At this time, the first optical interference layer (310) of the triple optical interference layer (300) can be deposited with a high refractive index material such as ZnS, TiO2, Nb2O5, ZrO2, the second optical interference layer (320) can be formed with a low refractive index material such as SiO2, NaF, CaF2, MgF2, and the third optical interference layer (330) can be manufactured with a metal layer such as Al, Ag.

[0060] Thus, the third optical interference layer (330) of the triple optical interference layer (300) is formed of metal, thereby achieving 200~500 cd / lux-m 2 The secondary optical interference layer (320), which is a low-refractive index layer, can be deposited to have a layer thickness of 0.7λ to 1.3λλ (where λ is the wavelength and n is the refractive index).

[0061] Alternatively, the triple optical interference layer (300) may be configured to be deposited with a high refractive index material such as ZnS, TiO2, Nb2O5, ZrO2, etc.

[0062] Meanwhile, the double optical interference layer (200) or triple optical interference layer (300) of the optical interference layer (400) deposited on the spherical surface of the glass bead (100) can be formed by vacuum deposition (dry coating) or wet coating, and various effects can be realized depending on the refractive index and thickness.

[0063] Here, dry coating includes PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition), and wet coating includes printing (Gravure, Offset, Inkjet, Screen, Slot Die, etc.), flow (Sheet Type Coating), spin (Sheet Type Coating), and dipping.

[0064] PVD (Physical Vapor Deposition) is a technique that vaporizes a metal to be deposited in a vacuum and deposits it onto a substrate without obstruction; it includes thermal evaporation, electron beam evaporation, and sputtering.

[0065] In particular, thermal evaporation is a technique in which solid and liquid evaporation feeds are evaporated into a gaseous state in a vacuum chamber, and the evaporated feeds move to a substrate and undergo a condensation process to be deposited.

[0066] Electron beam evaporation (E-Beam Evaporation) is a vacuum deposition method that utilizes high voltage between ionized metals, and it has the advantage of high film density because it uses electrons instead of heat for deposition.

[0067] Sputtering is a technique in which high-energy particles collide with a target (deposition material), causing target atoms to be emitted, and these emitted atoms are deposited on a substrate to form a substrate.

[0068] Figure 4 is a schematic diagram explaining the evaporation and sputtering methods of PVD.

[0069] As shown in Figure 4, thermal evaporation and electron beam evaporation are vacuum deposition methods that deposit on a TFT substrate using heat and electrons, and have the disadvantage of large air caps between particles and low packing density. On the other hand, sputtering is a deposition technique in which emitted atoms emitted from a plasma chamber are deposited on a TFT substrate, and has the advantage of small air caps between particles and high packing density.

[0070] Figure 5 is a schematic diagram explaining the deposition state by evaporation and sputtering of PVD.

[0071] As shown in Fig. 5, thin film deposition on a substrate by thermal evaporation or electron beam evaporation may have many voids within the thin film layer, while thin film deposition on a substrate by sputtering may have a very dense thin film layer state due to excellent packing density.

[0072] Furthermore, CVD (Chemical Vapor Deposition) is a technique for depositing by coating a wafer or substrate using gas reactions and ions, and can consist of a step in which gas is introduced into the deposition process, a step of adsorption and diffusion to the film surface of the substrate, and a step of deposition of the generated gas and thin film formation through surface bond activation.

[0073] Thin films produced by CVD can be significantly affected by the properties of the deposition substrate (amorphous, polycrystalline, crystalline) and deposition conditions (temperature, growth rate, pressure, etc.).

[0074] CVD (Chemical Vapor Deposition) includes Thermal (APCVD, LPCVD, MOCVD, HWCVD), PECVD (CCP, ICP, EEP), and Photo (Pyrolytic, photolytic).

[0075] In particular, PECVD (Plasma Enhanced CVD) is a technique that uses plasma to activate reaction gases and deposits thin films on a substrate using the activated gases. Since energy to dissociate the source gas is obtained from the plasma, the substrate temperature can be maintained at a relatively low level of 400°C or lower compared to Thermal CVD. Additionally, the decomposition rate of the source gas is very fast, which can lead to a reduction in process time. However, there are also disadvantages such as defects caused by charged particles and poor stoichiometric composition ratios due to the relatively low temperature.

[0076] FIG. 6 is a schematic diagram illustrating various deposition methods of an optical interference layer by sputtering in a retroreflective sheet having an optical interference layer according to an embodiment of the present invention. As shown in FIG. 6, in a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, the optical interference layer (400) can be deposited as a single layer through a single thin film deposition process, such as with Metal or Oxide, on glass beads (100) coated on a PE film (20) of a dispersion film.

[0077] In particular, as shown in FIG. 6, two layers of Metal or Oxide can be formed through a thin film deposition process by sputtering twice each, and three or more layers can be formed by alternately depositing Metal and Oxide. However, when the optical interference layer (400) of the retroreflective sheet having an optical interference layer according to an embodiment of the present invention is formed into m layers by repeating the thin film deposition process m (m is a natural number greater than or equal to 2), the physical properties and appearance of the thin film can be significantly improved due to the interface phenomenon of the thin film deposition.

[0078] For example, a thin film layer made of Al can be formed as a single layer through a single thin film deposition process using thermal evaporation or sputtering, but if it is formed as m layers through m thin film deposition processes, excellent adhesion between the substrate and the thin film layer is achieved and the bonding strength between the thin film layers is improved, thereby substantially improving the physical properties and appearance of the Al thin film layer.

[0079] Furthermore, the optical interference layer (400) of the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be configured to achieve an increase in brightness by maximizing retroreflectivity by enhancing the rainbow effect (iridescent effect) or color change effect through the matching of composite optical interference layers and minimizing light loss at the same time when forming m layers by repeating a thin film deposition process m times.

[0080] Meanwhile, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention has an optical interference layer (400) of a double optical interference layer (200) or a triple optical interference layer (300), so the reflectivity is very high and a beautiful image can be obtained.

[0081] Accordingly, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be mainly applied to shoes and can also be used in clothing, etc.

[0082] In particular, a retroreflective sheet having an optical interference layer according to an embodiment of the present invention can produce a rainbow effect (iridescent effect) or a color change effect when light is incident on it while being applied to shoes and clothing, etc.

[0083] In addition, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be suitably used in a liquid crystal display device and can be applied to a backlight device which is a surface light source device of a liquid crystal TV, a side light type surface light source device used in notebook computers, etc.

[0084] In addition, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be applied to lamp reflectors of direct-type display devices such as PDAs or mobile phones, in addition to LED backlights, projection televisions, and front lights.

[0085] Furthermore, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention may be used as a light-collecting material for a solar cell because it has a high reflectivity.

[0086] FIG. 6 is a flowchart illustrating a method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention.

[0087] As illustrated in FIG. 6, a method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention may include (a) a scatter film manufacturing step, (b) a glass bead coating step, (c) an optical interference layer deposition step, (d) a color layer coating step, (e) an adhesive resin layer coating step, (f) a backing substrate adhesion step, and (g) a scatter film removal step.

[0088] In the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (a) the step of manufacturing a dispersion film can be performed by laminating a PE film (polyethylene film; Polyethylene Film) (20) and a PET film (polyethylene terephthalate film; Polyethylene Terephthalate Film) (10) as shown in FIG. 1 to manufacture a dispersion film.

[0089] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (b) the glass bead coating step may be configured to apply glass beads (100) to the PE film (20) of the dispersion film.

[0090] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (c) the step of depositing an optical interference thin film layer may deposit an optical interference layer (400) as a reflective layer on a glass bead (100) coated on a PE film (20) of a dispersion film.

[0091] At this time, the optical interference layer (400) functioning as a reflective layer may be composed of a double optical interference layer (200) or a triple optical interference layer (300).

[0092] The double optical interference layer (200) of the optical interference layer (400) can be formed to consist of a first optical interference layer (210) and a second optical interference layer (220), and can be formed so that when the first optical interference layer (210) is deposited on the surface of the glass bead (100), the second optical interference layer (220) is deposited again on the surface of the first optical interference layer (210).

[0093] In the case of the first optical interference layer (210) deposited on the surface of the glass bead (100) in the double optical interference layer (200), it may be made of any one of Al, TiN, Ti, Cr, or Ni-Cr.

[0094] The double optical interference layer (200) can be configured to deposit a second optical interference layer (220) of ZnS on the surface of a first optical interference layer (210) made of any one of Al, TiN, Ti, Cr, and Ni-Cr.

[0095] Alternatively, if the first optical interference layer (210) in the double optical interference layer (200) is deposited with ZnS, the second optical interference layer (220) can be deposited with any one of Al, TiN, Ti, Cr, or Ni-Cr.

[0096] And, the triple optical interference layer (300) of the optical interference layer (400) may be composed of a first optical interference layer (310), a second optical interference layer (320), and a third optical interference layer (330).

[0097] In particular, the triple optical interference layer (300) forms a triple optical interference layer according to the refractive index, and the matching of the wavelength range, thickness, and refractive index of each layer can be realized, and from this, various color shift effects can be derived, thereby acting to maximize the rainbow effect.

[0098] The triple optical interference layer (300) may include a first optical interference layer (310) of high refractive index, a second optical interference layer (320) of low refractive index, and a third optical interference layer (330) of high refractive index.

[0099] In the triple optical interference layer (300), the first optical interference layer (310) can be deposited with a high refractive index material such as ZnS, TiO2, Nb2O5, ZrO2, the second optical interference layer (320) can be formed with a low refractive index material such as SiO2, NaF, CaF2, MgF2, and the third optical interference layer (330) can be manufactured as a metal layer such as Al, Ag.

[0100] In particular, the third optical interference layer (330) in the triple optical interference layer (300) can be configured to be deposited with a high refractive index material such as ZnS, TiO2, Nb2O5, ZrO2, instead of a metal layer such as Al, Ag, etc.

[0101] Also, the double optical interference layer (200) or triple optical interference layer (300) of the optical interference layer (400) deposited on the spherical surface of the glass bead (100) can be formed by vacuum deposition (dry coating) or wet coating, and various effects can be achieved depending on the refractive index and thickness.

[0102] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (d) the color layer coating step may coat a color layer (30) on the optical interference layer (400) of the glass bead (100).

[0103] Here, the color layer (30) can be formed by coating a single layer or a multilayer color film after thin film coating pretreatment such as halogen heating treatment and plasma surface treatment for the optical interference layer (400).

[0104] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (e) the adhesive resin layer coating step may form an adhesive resin layer (40) by coating an organic hybrid coating solution on a color layer (30).

[0105] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (f) the backing substrate adhesion step can be manufactured by adhering a backing substrate (50) using an adhesive resin layer (40) and laminating them.

[0106] At this time, the backing material (50) is used when attaching a retroreflective sheet to the surface of a product such as shoes or clothing by heat pressing, and can be formed from a sheet formed of a thermoplastic resin such as polyester, polyurethane, polyacrylic, polyolefin, TPE (Thermo Plastic Elastomer) or TPU (Thermoplastic Polyurethane).

[0107] The backing material (50) can be formed from a cloth or non-woven fabric, and a retroreflective sheet can be sewn and attached to a product such as shoes or clothing.

[0108] In the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (g) the scatter film removal step may be configured to use the scatter film, which is formed by laminating a PE film (polyethylene film) (20) and a PET film (polyethylene terephthalate film) (10), after the retroreflective sheet is completed, by removing the scatter film from the glass beads (100).

[0109]

[0110] Preferred embodiments are presented below to aid in understanding the present invention.

[0111] However, the following examples are provided only to aid in understanding the present invention, and the present invention is not limited by the following examples.

[0112]

[0113] [Example]

[0114] Item Comparative Example Example 1 Example 2 Number of Depositions 1 2 2 Deposited Material ZnS ZnS+Al ZnS+Al Setting Voltage (V) 11.5 ~ 12.0 8.5~9.0 9.5~10.0 Deposition Speed ​​(m / min) 120 (2 m / s) 90 (1.5 m / s) 120 (2 m / s)

[0115]

[0116] Looking at Table 1 above, in the comparative example, a single layer of ZnS optical interference thin film was deposited on glass beads by sputtering, the sputtering deposition setting voltage (V) was set to 11.5 to 12.0, and the deposition rate (m / min) was controlled to 120. On the other hand, in Example 1 and Example 2, a double optical interference thin film layer was deposited on glass beads by sputtering, the deposition setting voltage (V) was set to 8.5 to 9.0 and 9.5 to 10.0, respectively, and the deposition rate (m / min) was controlled to 90 and 120, respectively.

[0117]

[0118] [Correction pursuant to Rule 91 01.12.2025][Table 2]

[0119]

[0120] Table 2 above shows the luminance (cd / lux-m) for the retroreflective sheets prepared by the comparative example and Examples 1 and 2 conducted in Table 1. 2 ) was measured and expressed, and the quality of color deviation was evaluated and indicated. The luminance of the comparative example was 21 cd / lux-m 2 It was measured as, and the luminance of Example 1 and Example 2 was 51 cd / lux-m, respectively. 2, , 54 cd / lux-m 2, It was measured as.

[0121] Upon examination, in the comparative example, the deposition setting voltage (V) is excessively high, and the optical interference layer deposited on the glass beads is formed as a single layer of ZnS, which may reduce the matching effect of the optical interference layer, and thus the brightness may decrease along with the reduction in reflectance.

[0122] Ultimately, the quality of the color deviation for the comparative example was rated as average or low, and regarding non-reflective / reflective colors, the color deviation was excessively large and the color change effect was poor.

[0123] However, in Examples 1 and 2, the deposition setting voltage (V) was controlled to be 8.5 to 9.0 / 9.5 to 10.0 to create an optimal state, and the deposited optical interference layer of the glass beads was formed as a composite optical interference layer consisting of ZnS as the first optical interference layer and Al (silver film) as the second optical interference layer, thereby minimizing light loss and increasing reflectance, and it was found that the brightness was improved.

[0124] Furthermore, the quality of color deviation for Examples 1 and 2 was highly evaluated as very good and very good, respectively, and regarding non-reflective and reflective colors, color deviation was minimized, and features such as various colors being clearly visible depending on the viewing angle were realized.

[0125] FIG. 8 is an illustrative diagram explaining Example 1 and Example 2.

[0126] As shown in FIG. 8, in Example 1, when the thin film thickness is deposited at 1.32 μm or 1.13 μm, the color shift can be realized as Purple to Blue, and in Example 2, when the thin film thickness is deposited at 0.83 μm, the color shift can be realized as Purple to Green.

[0127]

[0128] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention may be configured such that an optical interference layer, which is a reflective layer, is deposited on the surface of a glass bead (100). The optical interference layer comprises one or more optical interference thin film layers, and at least one optical interference thin film layer may comprise ZnS. For example, the optical interference layer may comprise an optical interference thin film layer made of ZnS.

[0129] At this time, the optical interference thin film layer, which functions as a reflective layer, can be formed on the spherical surface of the glass bead (100) by vacuum deposition (dry coating) or wet coating, and various effects can be achieved depending on the refractive index and thickness.

[0130] Vacuum deposition (dry coating) or wet coating is as described above.

[0131] Meanwhile, the optical interference thin film layer deposited on the surface of the glass bead (100) in the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be applied with a thickness of 600 to 1000 nm.

[0132] At this time, the optical interference thin film layer of the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be formed as a single layer through a single thin film deposition process.

[0133] However, when the optical interference thin film layer of the retroreflective sheet having an optical interference layer according to an embodiment of the present invention is formed into m layers by repeating a thin film deposition process m (m is a natural number greater than or equal to 2), the physical properties and appearance of the thin film can be significantly improved due to the interface phenomenon of the thin film deposition.

[0134] For example, a 150 nm thin film layer made of ZnS can be formed as a single layer through a single thin film deposition process using thermal evaporation or sputtering, but if it is formed as m layers through m thin film deposition processes, excellent adhesion between the substrate and the thin film layer is achieved and the bonding strength between the thin film layers is improved, thereby substantially improving the physical properties of the ZnS thin film layer.

[0135] Furthermore, the optical interference thin film layer of the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be configured to achieve an increase in brightness resulting from the maximization of retroreflectivity by improving the rainbow effect (iridescent effect) or color change effect while minimizing light loss when the thin film deposition process is repeated m times to form m layers.

[0136] In addition, the optical interference thin film layer of the retroreflective sheet having an optical interference layer according to an embodiment of the present invention may be provided as a high-refractive index metal reflective layer of ZnS.

[0137] Alternatively, in a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, the optical interference thin film layer may be deposited with any one selected from ZnS, TiO2, Nb2O5, ZrO2, CeO2, Ta2O5, ZnTe, ZnSe, and BaTiO3, which are high refractive index materials with a refractive index of 2 or higher, instead of ZnS.

[0138] In particular, in a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, the optical interference thin film layer may be formed to consist of one or more layers of any one identical material selected from ZnS, TiO2, Nb2O5, ZrO2, CeO2, Ta2O5, ZnTe, ZnSe, and BaTiO3, or may be formed to consist of one or more layers of two or more heterogeneous materials selected from ZnS, TiO2, Nb2O5, ZrO2, CeO2, Ta2O5, ZnTe, ZnSe, and BaTiO3.

[0139] The optical interference thin film layer of the retroreflective sheet having an optical interference layer is provided as a high-refractive index metal reflective layer of ZnS, and at a wavelength of 632.8 nm, the refractive index (n) is 2.355 and the absorption rate (k) is 0.005.

[0140] Light has the characteristic of determining a path to reach two different points in the shortest possible time when traveling. The degree to which light bends in a medium is defined as the refractive index (RI), and the refractive index can generally vary depending on the wavelength of light.

[0141] At this time, ZnS (Zinc Sulfide), which forms the optical interference thin film layer, is a high-refractive index material with a refractive index of 2.40.

[0142] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention may have glass beads (100) applied to the PE film (20) in a dispersion film prepared by laminating a PE film (polyethylene film; Polyethylene Film) (20) and a PET film (polyethylene terephthalate film; Polyethylene Terephthalate Film) (10), and an optical interference thin film layer as a reflection layer may be deposited with a thickness of 600 to 1000 nm on the glass beads (100) applied to the PE film (20) of the dispersion film.

[0143] In addition, a retroreflective sheet having an optical interference layer according to an embodiment of the present invention may have a color layer (30) coated on the optical interference thin film layer of a glass bead (100).

[0144] At this time, the color layer (30) can be applied by coating a single layer or a multilayer color film after a thin film coating pretreatment such as halogen heating treatment and plasma surface treatment on the optical interference thin film layer.

[0145] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be manufactured by forming an adhesive resin layer (40) by coating an organic hybrid coating solution on a color layer (30), and then bonding a backing substrate (50) using the adhesive resin layer (40) to form a laminate.

[0146] At this time, the backing material (50) is used when attaching a retroreflective sheet to the surface of a product such as shoes or clothing by heat pressing, and can be formed from a sheet formed of a thermoplastic resin such as polyester, polyurethane, polyacrylic, polyolefin, TPE (Thermo Plastic Elastomer) or TPU (Thermoplastic Polyurethane).

[0147] In addition, the backing material (50) may be formed of a cloth or non-woven fabric, and the retroreflective sheet may be sewn and attached to a product such as shoes or clothing.

[0148] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be applied for use after removing a dispersion film, which is formed by laminating a PE film (polyethylene film) (20) and a PET film (polyethylene terephthalate film) (10) from a glass bead (100) once the product is completed.

[0149] A retroreflective sheet having an optical interference layer according to an embodiment of the present invention has a high refractive index optical interference thin film layer controlled to a specific thickness of 600 to 1000 nm, so it has a very high reflectivity and can also obtain a beautiful image.

[0150] Accordingly, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be mainly applied to shoes and can also be used in clothing, etc.

[0151] In particular, a retroreflective sheet having an optical interference layer according to an embodiment of the present invention can produce a rainbow effect (iridescent effect) or a color change effect when light is incident on it while being applied to shoes and clothing, etc.

[0152] In addition, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be suitably used in a liquid crystal display device and can be applied to a backlight device which is a surface light source device of a liquid crystal TV, a side light type surface light source device used in notebook computers, etc.

[0153] In addition, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention can be applied to lamp reflectors of direct-type display devices such as PDAs or mobile phones, in addition to LED backlights, projection televisions, and front lights.

[0154] Furthermore, the retroreflective sheet having an optical interference layer according to an embodiment of the present invention may be used as a light-collecting material for a solar cell because it has a high reflectivity.

[0155] A method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention is described.

[0156] A method for manufacturing a retroreflective sheet having an optical interference layer by refractive index matching according to an embodiment of the present invention may include (a) a scatter film manufacturing step, (b) a glass bead coating step, (c) an optical interference thin film layer deposition step, (d) a color layer coating step, (e) an adhesive resin layer coating step, (f) a backing substrate adhesion step, and (g) a scatter film removal step.

[0157] In the method for manufacturing a retroreflective sheet having an optical interference layer by refractive index matching according to an embodiment of the present invention, (a) the step of manufacturing a dispersion film can be performed by laminating a PE film (polyethylene film; Polyethylene Film) (20) and a PET film (polyethylene terephthalate film; Polyethylene Terephthalate Film) (10) to manufacture a dispersion film.

[0158] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer by refractive index matching according to an embodiment of the present invention, (b) the glass bead coating step may be configured to apply glass beads (100) to a PE film (20) of a dispersion film.

[0159] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer by refractive index matching according to an embodiment of the present invention, (c) the step of depositing an optical interference thin film layer can deposit an optical interference thin film layer as a reflective layer with a thickness of 600 to 1000 nm on a glass bead (100) coated on a PE film (20) of a dispersion film.

[0160] At this time, the optical interference thin film layer is deposited using ZnS thermal evaporation or sputtering methods, and while it can be formed as a single layer through a single thin film deposition process, if it is formed as m layers through m (m is a natural number greater than or equal to 2) thin film deposition processes, excellent adhesion between the substrate and the thin film layer is achieved, and the bonding strength between the thin film layers is improved, thereby substantially improving the physical properties of the ZnS thin film layer.

[0161] Alternatively, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, the optical interference thin film layer of step (c) may be deposited with any one selected from ZnS, TiO2, Nb2O5, ZrO2, CeO2, Ta2O5, ZnTe, ZnSe, and BaTiO3, which are high refractive index materials with a refractive index of 2 or higher.

[0162] In particular, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, the optical interference thin film layer of step (c) may be formed to have one or more layers of any one identical material selected from ZnS, TiO2, Nb2O5, ZrO2, CeO2, Ta2O5, ZnTe, ZnSe, and BaTiO3, or may be formed to have one or more layers of two or more heterogeneous materials selected from TiO2, Nb2O5, ZrO2, CeO2, Ta2O5, ZnTe, ZnSe, and BaTiO3.

[0163] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (d) the color layer coating step may coat a color layer (30) on the optical interference thin film layer of the glass bead (100).

[0164] Here, the color layer (30) can be formed by coating a single layer or a multilayer color film after a thin film coating pretreatment such as halogen heating treatment and plasma surface treatment on the optical interference thin film layer (200).

[0165] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (e) the adhesive resin layer coating step may form an adhesive resin layer (40) by coating an organic hybrid coating solution on a color layer (30).

[0166] In addition, in the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (f) the backing substrate adhesion step can be manufactured by using an adhesive resin layer (40) to adhere a backing substrate (50) and laminate it.

[0167] At this time, the backing material (50) is used when attaching a retroreflective sheet to the surface of a product such as shoes or clothing by heat pressing, and can be formed from a sheet formed of a thermoplastic resin such as polyester, polyurethane, polyacrylic, polyolefin, TPE (Thermo Plastic Elastomer) or TPU (Thermoplastic Polyurethane).

[0168] The backing material (50) can be formed from a cloth or non-woven fabric, and a retroreflective sheet can be sewn and attached to a product such as shoes or clothing.

[0169] In the method for manufacturing a retroreflective sheet having an optical interference layer according to an embodiment of the present invention, (g) the scatter film removal step may be configured to use the scatter film, which is formed by laminating a PE film (polyethylene film) (20) and a PET film (polyethylene terephthalate film) (10), after the retroreflective sheet is completed, by removing the scatter film from the glass beads (100).

[0170] When the optical interference thin film layer is deposited as a single layer, the reflectance decreases due to light loss, which may lead to a decrease in brightness. However, when the deposition setting voltage (V) is controlled to 8.5 to 10.0, the deposition rate (m / min) is controlled to 60 m / min or higher, and the thickness of the optical interference thin film layer reaches 620 nm or 960 nm, and it is deposited as two or three layers, respectively, light loss is minimized and the reflectance increases, thereby improving brightness. Furthermore, when deposited as two or three layers, excellent quality regarding color deviation is achieved, and when examining non-reflective / reflective colors, color deviation is minimized, and various colors can be clearly seen depending on the viewing angle.

[0171] The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it is added once again that the scope of protection of the present invention cannot be limited by obvious changes or substitutions in the technical field to which the present invention belongs.

[0172]

[0173] [Explanation of the symbol]

[0174] 10: PET film

[0175] 20: PE film

[0176] 30: Color layer

[0177] 40: Adhesive resin layer

[0178] 50: Backing material

[0179] 100: Glass beads

[0180] 400: Optical interference layer

Claims

1. A retroreflective sheet comprising glass beads coated on a dispersion film of a PE film (polyethylene film) and a PET film (polyethylene terephthalate film), an optical interference layer deposited on the glass beads, a color layer coated on the optical interference layer, and a backing substrate adhered to the color layer by an adhesive resin layer, wherein the optical interference layer is an optical interference thin film layer on which ZnS is deposited. A retroreflective sheet having an optical interference layer.

2. In Paragraph 1, The above optical interference thin film layer is, ZnS is deposited to a thickness of 600 to 1000 nm, A retroreflective sheet having an optical interference layer.

3. In Paragraph 1, The above optical interference thin film layer is, Deposited to have one or more layers of the same or different materials, A retroreflective sheet having an optical interference layer.

4. In Paragraph 1, The above optical interference thin film layer is, Deposited by thermal evaporation or sputtering, A retroreflective sheet having an optical interference layer. 5.(a) A step of manufacturing a dispersion film by laminating a PE film and a PET film; (b) a step of applying glass beads to the PE film; (c) A step of depositing an optical interference layer on the surface of the glass beads; (d) A step of forming a color layer by coating a color thin film on the optical interference layer; (e) a step of forming an adhesive resin layer by coating an organic hybrid coating solution onto the color layer; and (f) a step of adhering a backing substrate to the adhesive resin layer, and The above optical interference layer is an optical interference thin film layer on which ZnS is deposited, Method for manufacturing a retroreflective sheet having an optical interference layer.

6. In Paragraph 5, When the retroreflective sheet is completed in step (f) above, (g) A step of removing the dispersion film from the glass beads; including, Method for manufacturing a retroreflective sheet having an optical interference layer.

7. In Paragraph 5, In step (c) above, The above optical interference thin film layer is deposited by thermal evaporation or sputtering, Method for manufacturing a retroreflective sheet having an optical interference layer.

8. In Paragraph 5, In step (c) above, The above optical interference thin film layer is deposited at a setting voltage (V) of 8.5 to 10.0, Method for manufacturing a retroreflective sheet having an optical interference layer.

9. In Paragraph 5, In step (c) above, The above optical interference thin film layer is formed by depositing ZnS with a thickness of 600 to 1000 nm, Method for manufacturing a retroreflective sheet having an optical interference layer.

10. In Paragraph 5, In step (c) above, The above optical interference thin film layer is, Deposited to have one or more layers of the same or different materials, Method for manufacturing a retroreflective sheet having an optical interference layer.

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