KR20200023580A - Image film and transfer material - Google Patents

Abstract

Provided are an image film which is excellent in security, has a thin thickness, and can significantly reduce frequency of spherical aberration, and a transfer material including the image film. The image film includes: 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 to be opposite to the converging lens layer; a refractive layer positioned between the converging lens layer and the diverging lens layer; and a reflective layer located on the other surface of the base film.

Description

Image Films & Transfers {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 goods have soared. It's so sophisticated that it's hard to tell even the experts, so the damages to consumers who know it and buy it are genuine. The problem is that it is difficult to distinguish between genuine and counterfeit goods. In order to solve these problems, the company has been trying to develop technology at the enterprise level. However, due to problems such as the cost of research and application of security technology and the equipment necessary to check for forgery, the results are not getting effective results. Therefore, it is urgent to develop new security technology to cope with the increasing number of counterfeit goods.

In order to solve this problem, various authenticity discrimination methods have been developed. One of the methods for authenticity determination is to attach a label that cannot be easily forged by others through gold foil pressure or laser engraving. However, due to the development of printing technology or gold leaf technology, even the label can be easily reproduced, and thus the situation is not fully achieved.

Accordingly, a new method of film production, such as a label through a print process that causes a color change by heat, has been developed. In addition, a technology has been developed such that a trademark is displayed only when viewing a film from a certain angle by constructing a film by using a hidden image that is not represented in a general state but when a change of a specific state occurs. . Hidden images are printed on transparent or translucent substrates in a form that makes it difficult to identify specific information by saturation and brightness, and then hides the hidden information by illuminating the substrate with a light on the monitor (change of specific state). There is a way to do it. That is, in the conventional hidden image expression, a method of causing visual illusion by changing the brightness and saturation of the background and the image painted with a dye or a pigment, or by making the background or the image consist of fine and complex patterns or symbols.

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

Accordingly, a three-dimensional lens sheet capable of reconstructing a planar 2D image into a three-dimensional image by using a principle of optical illusion due to binocular disparity using a lenticular or microlens is being illuminated. In the conventional three-dimensional image display method through a three-dimensional lens sheet, by combining a lenticular lens or a microlens on the image represented by the dye or pigment to take advantage of the three-dimensional and various transformation effects of the image. In other words, the most important factor to feel the three-dimensional feeling is to use the binocular disparity that appears because the human eye is located about 65mm in the horizontal direction, using a three-dimensional lens, the blocking effect of some images and the advancement of selective light By using the effect, the effect of the three-dimensional stereoscopic image can be obtained from the two-dimensional plane image.

One embodiment can provide an image film that is excellent in security, but thin, and can greatly reduce the incidence of spherical aberration.

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

An embodiment 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, a diverging lens layer positioned to face the converging lens layer, and between the converging lens layer and the diverging lens layer. It provides an image film comprising a refractive layer located on and a reflective layer located on the other side 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 that of the refractive layer.

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

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 (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 diverging 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 (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 invention are included in the following detailed description.

The image film according to the embodiment uses two different types of lenses, and together with the reflection layer, it is possible to provide a sharp image with a thin thickness while greatly reducing the frequency of spherical aberration, to use for security purposes Excellent in

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

Preferred embodiments of the present invention will be described in detail. 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 so that the disclosure may be made thorough and complete, and to fully convey the spirit of the invention to those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. However, in describing the preferred embodiment of the present invention in detail, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof 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, throughout the specification, when a part is 'connected' to another part, it is not only 'directly connected' but also 'indirectly connected' with another element in between. Include. In addition, the term 'comprising' a certain component means that the component may further include other components, not to exclude other components unless specifically stated otherwise.

An embodiment of the present invention relates to an image film representing a stereoscopic image, wherein the image film is opposite to the base film, an image layer positioned on one side of the base film, a converging lens layer positioned on one side of the image layer, and the converging lens layer. 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 the embodiment is not exposed to the outside of the lens layer is not concerned with external damage, and above all, since the lens structure is present inside the image film, there is little concern for duplication and theft, so it may be used as an image film for security purposes. Very suitable. Furthermore, unlike the conventional method, the focal length is reduced by simultaneously applying the converging lens layer and the diverging lens layer. In general, when two different lens layers are applied together, spherical aberration frequency increases as the focal length decreases. In one embodiment, the converging lens layer and the diverging lens layer are positioned to face each other. Solved. In addition, the image film according to the embodiment further includes a reflective layer, a clear image can be obtained through the reflective layer, depending on the brightness of the light, for example, light transmittance, that is, the image in the bright and dark place with each other The effect of making it different can be implemented, which can be very useful for security purposes. On the other hand, since the image film according to the embodiment further includes a reflective layer, the film thickness is inevitably thickened. As described above, by applying the converging lens and the diverging lens together at positions opposite to each other, the image film has the same level as 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. The converging lens layer and the diverging lens layer may be simultaneously applied to positions opposite to each other, but the above-described effect may be realized, but the refractive index difference is also very important. By satisfying the difference in refractive index, the image film according to the embodiment can appropriately adjust the thickness thereof. For example, when 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 the application. When the difference in refractive index is more than 0.45, the thickness of the film is thin. The efficiency of reducing the focal length is reduced, which reduces the optical field of view (which allows the image to be seen clearly), and the occurrence of spherical aberrations at the interface of the lens is often undesirable.

Conventionally, since there was no image film having the same configuration as the image film according to the embodiment, it is possible to implement a clear image, but the thickness of the film is limited to apply to other applications, or the film is thin but the optical viewing angle is narrow and the image is narrow There is a problem in that it is not visible, or the lens is protruded to the outside, causing damage to the film, even if not used for a while, in general, using the hologram to manufacture a film for security purposes, according to one embodiment according to the thin thickness, Since wide viewing angle and prevention of external damage to the film can be achieved, it is possible to manufacture a film for security purposes by utilizing various images instead of holograms.

The convergence 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, for example, 30 to 40, for example, 30. When both the converging lens and the diverging lens have a high rate radius of the above range, it is easy to implement the aforementioned refractive index difference.

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

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

The image film may have a thickness of 71 μm to 86 μm. Image film having a thickness in the above range is applicable to most applications, the use range is very wide.

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

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 the metal is a metal other than the above-described metal, it may be difficult to exhibit a function as a reflective layer due to low light reflectance. For example, the reflective layer may be silver paste.

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

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

The protective film may prevent the lens from being exposed to the outside, thereby greatly reducing 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, Polyimide), polyurethane (PU, Polyurethane) or thermoplastic polyurethane (TPU, Thermoplastic Polyurethane), but if the film can be printed and imprinted can be used as the protective film and the base film have.

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

For example, the transfer material may 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 the image film to the molded article. According to the embodiment, it can be formed using various well-known thermosensitive or pressure-sensitive resins, For example, polyacrylic resin, polystyrene resin, polyamide type, chlorinated polyolefin resin, chlorinated ethylene-vinyl acetate copolymer resin Or it may be formed using a rubber resin or the like, but is not necessarily limited thereto.

The release film is to be peeled off after adhesion to the molded article, it may be formed on the top of the image film. According to the embodiment, a resin film mainly containing polypropylene resin, polyethylene resin, polyamide resin, polyester resin, polyacrylic resin or polyvinyl chloride resin, and metal foil such as aluminum foil or copper foil , A release film may be formed by forming a release layer by forming a release layer by performing a release treatment on one surface of the substrate, such as a cellulose 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, epoxy-melamine, amino alkyd, acrylic, melamine, silicone, fluorine, cellulose, urea resin, polyolefin, It can be formed using various printing methods or coating methods using paraffin-based or two or more of the above-mentioned complex release agent.

The image film according to an embodiment may further comprise an adhesive layer and a release film as described above, and may be used in a manner of transferring the transfer material onto the surface of a desired molded article.

In the transfer method of the transfer material including the image film to the molded article according to one embodiment, the adhesive layer of the transfer material is disposed so as to contact the surface of the molded article, the temperature is about 80 ℃ to 260 ℃, pressure 50kg / ㎡ to 200kg / ㎡ Under the conditions, if heat and pressure are applied to the release film side with a transfer member such as a heat-resistant rubber-like elastomer, 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 article. Can be. However, this is only an example, and in addition, the image film may be transferred to the molded article by various methods such as a mold injection method.

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

Film according to one embodiment can be used in a variety of applications, such as most of the exterior used in portable electronic devices, such as a keypad of a mobile phone. Furthermore, the image film according to one embodiment is useful for a variety of products that require three-dimensional representation of 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

The thickness of the coating film composed of the diverging lens layer, the refraction layer and the converging lens layer is 18 µm, and the refractive index difference between the diverging lens layer (and the converging lens layer) and the refraction layer is Δn. ) To 0.31, and an image film (lens curvature 30) having a thickness of 86 ㎛ 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 0.45.

Comparative Example 1

A metal paste having a thickness of 1 μm is used as the reflective layer, and the thickness of the coating film including the divergent lens layer and the refractive layer is 18 μm, and the refractive index difference Δn between the divergent lens layer and the refractive layer is 0.31, and the thickness is 93 μm. An image film (lens curvature 30) having 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 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 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 no converging lens layer was 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 0.45.

Evaluation: thickness and spherical aberration of image film

The total thickness and spherical aberration of the image film according to Example 1, Example 2 and Comparative Examples 1 to 6 were confirmed, 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

△: spherical aberration occurrence frequency is small

X: high frequency 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, although the image film according to the embodiment includes a reflective layer, compared with the image film according to the comparative example, it can be seen that the production of a thin film image, a very low spherical aberration occurrence frequency is possible. . In addition, it can be seen that by limiting the refractive index difference between the lens layer and the refractive layer to 0.31 to 0.45, the spherical aberration occurrence frequency can be greatly reduced while controlling the thickness to less than 90 μm.

The present invention is not limited to the above embodiments, but may be manufactured in various forms, and a person skilled in the art to which the present invention pertains does not change the technical spirit or essential features of the present invention. It will be appreciated that the present invention may be practiced as. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

1: base film
2: image layer
3: converging lens layer
4: refractive layer
5: diverging 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 facing the converging lens layer, and a refraction positioned between the converging lens layer and the diverging lens layer An image film comprising a layer and a reflective layer located on the other side of the base film.
In claim 1,
The refractive index difference between the converging lens layer and the refractive layer is an image film of 0.31 to 0.45.
In claim 1,
The refractive index difference between the divergent lens layer and the refractive layer is an image film of 0.31 to 0.45.
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.
In claim 1,
The image film has a thickness of 71㎛ to 86㎛.
In claim 1,
And the reflective layer is a metal deposition layer.
In claim 6,
And the metal comprises Ag, Cr, Ni, Ti, or a combination thereof.
In claim 1,
The reflective layer has an optical 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 comprises a protective film located 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 coat image film.
Transfer material comprising the image film according to any one of claims 1 to 12.

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