KR102101628B1 - Image film and transfer material - Google Patents

Abstract

A base film, an image layer positioned on one surface of the base film, a converging lens layer positioned on one surface of the image layer, a diverging lens layer positioned opposite the converging lens layer, and a refraction positioned between the converging lens layer and the diverging lens layer An image film including a layer and a reflective layer positioned on the other surface of the substrate film and a transfer material including the image film are provided.

Description

Image film and transfer material {IMAGE FILM AND TRANSFER MATERIAL}

The present invention relates to a security image film and a transfer material comprising the image film.

With the recent development of mobile devices, counterfeit products are rapidly increasing. Since it is manufactured to be sophisticated enough to discriminate even experts, the damage of consumers who know and buy as genuine products has reached a considerable level. The problem is that it is difficult to distinguish counterfeit products from genuine products. In the meantime, efforts have been made to develop technologies at the corporate level to solve these problems, but it is not possible to obtain effective results due to problems such as cost for research and application of security technologies and equipment required to check for forgery. Accordingly, it is urgent to develop a new security technology to cope with the increasing number of counterfeit products.

Various authenticity discrimination methods have been developed to solve this problem. As one of the methods for discrimination of authenticity, a label that other people cannot forge and manufacture through gold foil or laser engraving may be attached. However, due to the development of printing technology or gold foil technology, even the corresponding label can be reproduced without difficulty, and thus, the purpose has not been sufficiently achieved.

Accordingly, new types of film manufacturing technologies such as labels through print processing that cause color changes by heat are being developed. In addition, a technology has been developed to configure a film by using a hidden image that is not expressed in a general state but is displayed when a specific state is changed, so that the corresponding trademark or the like is displayed only when the film is viewed from a specific angle. . As a method of expressing hidden images, it is difficult to identify specific information by saturation and lightness, and after printing on a transparent or translucent substrate, the substrate is illuminated by the light of the monitor (change in a specific state) to identify hidden information. There is a way to do it. That is, the conventional hidden image expression used a method of causing visual illusion by changing the brightness or saturation of the background and the image painted with a dye or pigment, or by making the background or image composed of fine and complicated patterns or symbols.

As described above, a film produced by printing using a conventional dye or pigment is merely a representation of a two-dimensional image, and there is also a problem of discoloration of the dye or pigment by ultraviolet rays.

Accordingly, a three-dimensional lens sheet that can reconstruct a planar 2D image into a three-dimensional image using a lenticular or micro lens using an optical illusion principle by binocular parallax is illuminated. In the conventional method for expressing a stereoscopic image through a stereoscopic lens sheet, a lenticular lens or a microlens is combined on an image represented by a dye or pigment to use a stereoscopic effect and various conversion effects of the corresponding image. In other words, the most important factor for feeling the stereoscopic effect is to use a binocular disparity that occurs because the human eye is present about 65 mm apart in the horizontal direction. When a stereoscopic lens is used, the blocking effect of some images and selective light advancement By using the effect, it is possible to obtain the effect of a 3D stereoscopic image as a 2D plane image.

One embodiment can provide an image film that is excellent in security, has a thin thickness, and can significantly reduce the frequency of spherical aberration.

Another embodiment relates to a transfer material including the image film.

In one embodiment, a base film, an image layer positioned on one surface of the base film, a converging lens layer positioned on one surface of the image layer, a diverging lens layer positioned opposite to the converging lens layer, between the converging lens layer and the diverging lens layer It provides an image film including a refractive layer positioned on the reflective layer positioned on the other surface of the base film.

The difference in refractive index between the converging lens layer and the refractive layer may be 0.31 to 0.45.

The difference in refractive index between the divergent lens layer and the refractive layer may be 0.31 to 0.45.

The refractive index of each of the converging lens layer and the diverging lens layer may be greater than the refractive index of the refractive layer.

The image film may have a thickness of 71㎛ to 86㎛.

The reflective layer may be a metal deposition layer.

The metal may include Ag, Cr, Ni, Ti, or a combination thereof.

The reflective layer may have a light transmittance of 25% to 50%.

The base film is polyethylene (PE, Polyethylene), polyethylene terephthalate (PET, Polyethylene terephthalate), polyvinyl chloride (PVC, Polyvinyl chloride), polycarbonate (PC, Polycarbonate), polypropylene (PP, Polypropylene), polyimide It may be (PI, Polyimide), polyurethane (PU, Polyurethane) or thermoplastic polyurethane (TPU, Thermoplastic Polyurethane).

The image film may further include a protective film positioned on one surface of the divergent lens layer.

The protective film is polyethylene (PE, Polyethylene), polyethylene terephthalate (PET, Polyethylene terephthalate), polyvinyl chloride (PVC, Polyvinyl chloride), polycarbonate (PC, Polycarbonate), polypropylene (PP, Polypropylene), polyimide It may be (PI, Polyimide), polyurethane (PU, Polyurethane) or thermoplastic polyurethane (TPU, Thermoplastic Polyurethane).

The protective film may be hard-coated.

Another embodiment provides a transfer material including the image film.

Other details of aspects of the present invention are included in the detailed description below.

The image film according to one embodiment uses two different types of lenses, and further includes a reflective layer to provide a clear image with a thin thickness while greatly reducing the frequency of spherical aberration, and using it for security purposes. It is excellent.

1 is a view showing the configuration of an image film according to an embodiment of the present invention.

It will be described in detail preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete and that the spirit of the present invention is sufficiently conveyed to those skilled in the art.

Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily implement the present invention. However, in the detailed description of a preferred embodiment of the present invention, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the same or similar reference numerals are used throughout the drawings for parts having similar functions and functions.

In addition, in the entire specification, when a part is said to be 'connected' with another part, it is not only 'directly connected', but also 'indirectly connected' with another element in between. Includes. In addition, "including" a component means that other components may be further included instead of excluding other components, unless otherwise stated.

One embodiment is for an image film representing a three-dimensional image, the image film is a base film, an image layer positioned on one surface of the base film, a converging lens layer positioned on one surface of the image layer, facing the converging lens layer It includes a diverging lens layer positioned, a refractive layer positioned between the converging lens layer and the diverging lens layer, and a reflective layer positioned on the other surface of the base film.

The image film according to one embodiment has no fear of external damage because the lens layer is not exposed to the outside, and most of all, since the lens structure exists inside the image film, there is little fear of duplication and theft, so it is used as an image film for security purposes. Very suitable. Furthermore, unlike the conventional method, the focal length was reduced by applying the converging lens layer and the divergent lens layer at the same time. In general, when two different types of lens layers are applied together, there is a problem that the frequency of spherical aberration increases as the focal length decreases. In one embodiment, the converging lens layer and the diverging lens layer are positioned to face each other, such a problem. Solved. In addition, the image film according to an embodiment further includes a reflective layer, and a clear image can be obtained through the reflective layer, and according to the brightness of light, for example, light transmittance, that is, images in a bright place and in a dark place Since it can implement the effect of making it different, it can be very useful for security purposes. On the other hand, since the image film according to one embodiment further includes a reflective layer, the film thickness is inevitably increased. As described above, by applying the converging lens and the diverging lens together at positions facing each other, the level is equivalent to that of the conventional image film. Alternatively, a thinner thickness can be achieved.

The difference in refractive index between the converging lens layer and the refractive layer may be 0.31 to 0.45, and the difference in refractive index between the diverging lens layer and the refractive layer may be 0.31 to 0.45. Although the above-described effect can be realized by simultaneously applying the converging lens layer and the diverging lens layer to opposite positions, the difference in refractive index is also very important. By satisfying the difference in refractive index, the thickness of the image film according to one embodiment can be appropriately adjusted. For example, if the difference in refractive index is less than 0.31, the thickness of the film becomes too thick, for example, it has a thickness of 90 µm or more, and thus there is a limit in utilizing / applying it to the application. If the difference in refractive index is greater than 0.45, the film thickness is thin. Since the efficiency to reduce the focal length is reduced, the wide viewing angle (which can clearly see the image) is reduced, and the frequency of spherical aberration at the interface of the lens is increased, which is undesirable.

In the past, there was no image film having the same configuration as the image film according to one embodiment, so a clear image is realized, but the thickness of the film is limited to apply to other applications, or the thickness of the film is thin but the image viewing angle is narrow due to the narrow viewing angle. There is a problem in that it is not clearly visible or a lens is protruded to the outside, and there is a problem of damage to the film even though it has not been used for a while. In general, a film for security purposes was manufactured using a hologram, but according to one embodiment, a thin thickness, Since it can achieve both wide viewing angle and prevention of external damage to the film, it is possible to manufacture a film for security purposes by utilizing various images rather than holograms.

The converging lens of the converging lens layer and the diverging lens of the diverging lens layer may each independently have a radius of curvature of 30 to 50, such as 30 to 40, such as 30. When both the converging lens and the diverging lens have a high-radius radius in the above range, it is easy to realize the difference in refractive index described above.

The refractive index of each of the converging lens layer and the diverging lens layer may be greater than the refractive index of the refractive layer.

The shape of the lens is not limited in shape, and any shape that can be arranged, such as a triangle, a square, a hexagon, or a circle, may be possible. For example, in addition to the basic lens shape, a reticular bar type (one-shaped) lens shape is also possible. For example, after arranging a round lens shape in the divergent lens layer, it is also possible to use a single-shaped rod-shaped lens in the converging lens layer, and vice versa.

The image film may have a thickness of 71㎛ to 86㎛. The image film having the thickness in the above range can be applied to most applications, so its use range is very wide.

The reflective layer may be a metal deposition layer. The reflective layer may be deposited by sputtering or e-beam the metal.

The metal may include Ag, Cr, Ni, Ti, or a combination thereof. For example, the metal may be Ag, Cr, Ni, Ti, or a combination thereof. For example, the metal may be Ag. When a metal other than the above-mentioned metal is used, the light reflectance may be low and it may be difficult to exert a function as a reflective layer. For example, the reflective layer may be a silver paste.

For example, the reflective layer may have a light transmittance of 25% to 50%. When the reflective layer has a light transmittance in the above range, it is possible to more clearly implement the above-described effect (the effect that the images in the dark and the dark are different from each other).

The image film according to an embodiment may further include a protective film positioned on one surface of the divergent lens layer. For example, the protective film may be hard coated.

The protective film prevents the lens from being exposed to the outside, thereby greatly reducing the risk of external damage, and may further have a higher hardness through a heart coating process.

The protective film and the base film are each independently polyethylene (PE, Polyethylene), polyethylene terephthalate (PET, Polyethylene terephthalate), polyvinyl chloride (PVC, Polyvinyl chloride), polycarbonate (PC, Polycarbonate), polypropylene (PP , Polypropylene), polyimide (PI), polyurethane (PU, Polyurethane) or thermoplastic polyurethane (TPU, Thermoplastic Polyurethane), but can be used as the protective film and the base film if the film can be printed and imprinted have.

On the other hand, another embodiment of the present invention provides a transfer material including the above-described image film.

For example, the transfer material may be configured to include the image film, an adhesive layer formed on the lower portion of the image film, and a release film formed on the lens layer or the protective film of the image film.

The adhesive layer may be formed under the image forming layer or the light shielding layer of the image film, and may serve to fix and attach the image film to the molded article. Depending on the embodiment, it can be formed using various known thermosensitive or pressure-sensitive resins, for example, polyacrylic resin, polystyrene resin, polyamide-based, chlorinated polyolefin-based resin, chlorinated ethylene-vinyl acetate copolymer resin Or it may be formed using a rubber-based resin, but is not limited thereto.

The release film, which is peeled after adhesion to the molded article, may be formed on the top of the image film. Depending on the embodiment, a resin film mainly made of polypropylene-based resin, polyethylene-based resin, polyamide-based resin, polyester-based resin, polyacrylic-based resin or polyvinyl chloride-based resin, and metal foil such as aluminum foil or copper foil A release film may be formed by forming a release layer by performing a release treatment on one surface of the substrate, using a cellulose-based sheet such as glycine paper, coated paper or cellophane, or a composite sheet of two or more of the above. . In this case, the release treatment method for forming the release layer is not particularly limited, for example, epoxy-based, epoxy-melamine-based, amino-alkyd-based, acrylic-based, melamine-based, silicone-based, fluorine-based, cellulose-based, urea resin-based, polyolefin-based, It may be formed using various printing methods or a coating method using a paraffin-based or a composite release agent of two or more of the above.

The image film according to an embodiment may further include an adhesive layer and a release film as described above to constitute a transfer material, and may be used as a method of transferring it to a surface of a desired molded product.

As a transfer method of a transfer material including an image film according to an embodiment to a molded article, the adhesive layer of the transfer material is placed so as to contact the surface of the molded article, the temperature is about 80 ° C to 260 ° C, and the pressure is 50kg / m2 to 200kg / m2 Under conditions, when heat and pressure are applied to the release film side with a transfer device such as a heat-resistant rubber-like elastic body, and then the release film is peeled off after the cooling process, peeling occurs at the interface between the image film and the release film, and the image film is transferred to the surface of the molded product. Can be. However, this is limited to one embodiment, and in addition, the image film may be transferred to a molded product by various methods such as a mold injection method.

The material of the molded article is not particularly limited. For example, the molded product may be a resin molded product, a woodworking product, a metal product, a composite product of two or more of the above, or any other molded product requiring hard coating. As the resin of the resin molded article, general-purpose resins such as polystyrene-based resins, polyolefin-based resins, ABS resins, AS resins, or AN resins may be mentioned. In addition, polyphenylene oxide polystyrene resins, polycarbonate resins, polyacetal resins, acrylic resins, polycarbonate modified polyphenylene ether resins, polyethylene terephthalate resins, polybutylene terephthalate resins, or ultra high molecular weight polyethylene resins, etc. Universal engineering resin, polysulfone resin, polyphenylene sulfide resin, polyphenylene oxide resin, polyacrylate resin, polyetherimide resin, polyimide resin, liquid crystal polyester resin, polyaryl heat resistant resin, super Engineering resins can also be used. In addition, in the present invention, a composite resin to which a reinforcing material such as glass fiber or inorganic filler is added can also be used.

The film according to one embodiment may be used in most fields used in portable electronic devices, such as keypads of mobile phones in various fields. Furthermore, the image film according to one embodiment is useful for various products that require three-dimensional representation such as business cards, credit cards, decorative materials, keypads, packaging materials, switches, sidewalk blocks, coasters, billboards, interior accessories, wallpaper, photos, cards, etc. Can be utilized.

Example

Example 1

A metal paste having a thickness of 1 μm is used as a reflective layer, and the thickness of a coating film composed of a diverging lens layer, a refractive layer, and a converging lens layer is 18 μm, but a difference in refractive index (Δn) between the diverging lens layer (and the converging lens layer) and the refractive layer ) To 0.31, and an image film (lens curvature 30) having a thickness of 86 μm was prepared.

Example 2

An image film (lens curvature 30) having a thickness of 71 μm was prepared in the same manner as in Example 1, except that Δn was set to 0.45.

Comparative Example 1

A metal paste having a thickness of 1 μm was used as a reflective layer, and the thickness of a coating film composed of a diverging lens layer and a refractive layer was 18 μm, but the difference in refractive index (Δn) between the diverging lens layer and the refractive layer was 0.31, resulting in a thickness of 93 μm. An image film having a (lens curvature 30) was prepared.

Comparative Example 2

An image film (lens curvature 30) having a thickness of 76 μm was prepared in the same manner as in Comparative Example 1, except that Δn was set to 0.45.

Comparative Example 3

An image film (lens curvature 30) having a thickness of 111 μm was prepared in the same manner as in Example 1, except that the reflective layer was not included.

Comparative Example 4

An image film (lens curvature 30) having a thickness of 91 μm was prepared in the same manner as in Comparative Example 3, except that Δn was set to 0.45.

Comparative Example 5

An image film (lens curvature 30) having a thickness of 153 μm was prepared in the same manner as in Comparative Example 3, except that the converging lens layer was not included.

Comparative Example 6

An image film (lens curvature 30) having a thickness of 113 μm was prepared in the same manner as in Comparative Example 5, except that Δn was set to 0.45.

Evaluation: Whether the image film thickness and spherical aberration occurred

The overall thickness and spherical aberration of the image films according to Example 1, Example 2 and Comparative Examples 1 to 6 were checked, and the results are shown in Table 1 below. The overall thickness of the image film was measured using a micrometer.

(Evaluation of spherical aberration)

○: No spherical aberration

△: The frequency of spherical aberration is small

X: Frequent occurrence of spherical aberration

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Thickness (㎛) 86 71 93 76 111 91 153 113 Whether spherical aberration occurs ○ ○ X X X X X X

From Table 1, it can be seen that despite the fact that the image film according to the embodiment includes a reflective layer, compared with the image film according to the comparative example, the frequency of occurrence of spherical aberration is very low. . In addition, it is also confirmed that the frequency of occurrence of spherical aberration can be significantly reduced while simultaneously controlling the thickness to less than 90 μm by limiting the difference in refractive index between the lens layer and the refractive layer to 0.31 to 0.45.

The present invention is not limited to the above embodiments, but may be manufactured in various different forms, and those skilled in the art to which the present invention pertains have other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that can be carried out. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

1: base film
2: Image layer
3: Converging lens layer
4: refractive layer
5: divergent lens layer
6: reflective layer
7: protective film

Claims (13)

A base film, an image layer positioned on one surface of the base film, a converging lens layer positioned on one surface of the image layer, a diverging lens layer positioned opposite the converging lens layer, and a refraction positioned between the converging lens layer and the diverging lens layer A layer and a reflective layer positioned on the other surface of the base film,
The difference in refractive index between the converging lens layer and the refractive layer is 0.31 to 0.45,
The difference in refractive index between the divergent lens layer and the refractive layer is 0.31 to 0.45,
Image film having a thickness of 71㎛ to 86㎛.
delete delete In claim 1,
The refractive index of each of the converging lens layer and the diverging lens layer is larger than the refractive index of the refractive layer.
delete In claim 1,
The reflective layer is an image film that is a metal deposition layer.
In claim 6,
The metal is an image film containing Ag, Cr, Ni, Ti, or a combination thereof.
In claim 1,
The reflective layer is an image film having a light transmittance of 25% to 50%.
In claim 1,
The base film is polyethylene (PE, Polyethylene), polyethylene terephthalate (PET, Polyethylene terephthalate), polyvinyl chloride (PVC, Polyvinyl chloride), polycarbonate (PC, Polycarbonate), polypropylene (PP, Polypropylene), polyimide (PI, Polyimide), polyurethane (PU, Polyurethane) or thermoplastic polyurethane (TPU, Thermoplastic Polyurethane).
In claim 1,
The image film further includes a protective film positioned on one surface of the divergent lens layer.
In claim 10,
The protective film is polyethylene (PE, Polyethylene), polyethylene terephthalate (PET, Polyethylene terephthalate), polyvinyl chloride (PVC, Polyvinyl chloride), polycarbonate (PC, Polycarbonate), polypropylene (PP, Polypropylene), polyimide (PI, Polyimide), polyurethane (PU, Polyurethane) or thermoplastic polyurethane (TPU, Thermoplastic Polyurethane).
In claim 10,
The protective film is a hard-coated image film.
A transfer material comprising the image film according to any one of claims 1, 4 and 6 to 12.

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